1
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Hertler PR, Yu X, Brower JD, Nguyen TAD, Wu G, Autschbach J, Hayton TW. Exploring Spin-Orbit Effects in a [Cu 6Tl] + Nanocluster Featuring an Uncommon Tl-H Interaction. Chemistry 2024; 30:e202400390. [PMID: 38381600 DOI: 10.1002/chem.202400390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Reaction of [CuH(PPh3)]6 with 1 equiv. of Tl(OTf) results in formation of [Cu6TlH6(PPh3)6][OTf] ([1]OTf]), which can be isolated in good yields. Variable-temperature 1H NMR spectroscopy, in combination with density functional theory (DFT) calculations, confirms the presence of a rare Tl-H orbital interaction. According to DFT, the 1H chemical shift of the Tl-adjacent hydride ligands of [1]+ includes 7.7 ppm of deshielding due to spin-orbit effects from the heavy Tl atom. This study provides valuable new insights into a rare class of metal hydrides, given that [1][OTf] is only the third isolable species reported to contain a Tl-H interaction.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260
| | - Jordan D Brower
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Thuy-Ai D Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106
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2
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Nguyen TH, Pauly C, Kent GT, Wu G, Hayton TW. Dimerization and ring-opening in bis(diisopropylamino)cyclopropenylidene (BAC) mediated by [U(NR 2) 3(CCPh)] (R = SiMe 3). Dalton Trans 2023; 52:13868-13871. [PMID: 37751280 DOI: 10.1039/d3dt02741d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Addition of 2 equiv. of bis(diisopropylamino)cyclopropenylidene (BAC) to [U(NR2)3(CCPh)] (1, R = SiMe3), in Et2O, results in formation of [cyclo-N(iPr)C(Me)2CH(NiPr2)C{CHC3(NiPr2)2}][U(NR2)2(N(SiMe3)SiMe2CH2)(CCPh)] (2) in moderate isolated yield. Complex 2 is the result of coupling and protonation of two BAC molecules, where complex 1 contributes the required proton. It was characterized by NMR spectroscopy and X-ray crystallography and represents a new mode of reactivity of the cyclopropenylidene fragment.
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Affiliation(s)
- Thien H Nguyen
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Christophe Pauly
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
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3
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Ordoñez O, Yu X, Wu G, Autschbach J, Hayton TW. Quantifying Actinide-Carbon Bond Covalency in a Uranyl-Aryl Complex Utilizing Solution 13C NMR Spectroscopy. Inorg Chem 2023. [PMID: 37788299 DOI: 10.1021/acs.inorgchem.3c02440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Reaction of [UO2Cl2(THF)2]2 with in situ generated LiFmes (FmesH = 1,3,5-(CF3)3C6H3) in Et2O resulted in the formation of the uranyl aryl complexes [Li(THF)3][UO2(Fmes)3] ([Li(THF)3][1]) and [Li(Et2O)3(THF)][UO2(Fmes)3] ([Li(Et2O)3(THF)][1]) in good to moderate yields after crystallization from hexanes and Et2O, respectively. Both complexes were characterized by X-ray crystallography and NMR spectroscopy. DFT calculations reveal that the Cispo resonance in [1]- exhibits a deshielding of 51 ppm from spin-orbit coupling effects originating at uranium, which indicates an appreciable covalency in the U-C bonding interaction.
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Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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4
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Baeza Cinco MÁ, Wu G, Hayton TW. Photolytic C-Diazeniumdiolate Disassembly in the β-Diketiminate Complexes [ MeLM(O 2N 2CPh 3)] (M = Fe, Co, Cu). Inorg Chem 2023; 62:14064-14071. [PMID: 37584511 DOI: 10.1021/acs.inorgchem.3c02188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
The reaction of [K(18-crown-6)][O2N2CPh3] with [MeLCo(μ-Br)2Li(OEt2)] (MeL = {(2,6-iPr2C6H3)NC(Me)}2CH) generates the trityl diazeniumdiolate complex, [MeLCo(O2N2CPh3)] (1), in moderate yield. Similar metathesis reactions result in the formation of the Fe and Cu analogues, [MeLM(O2N2CPh3)] (Fe, 2; Cu, 3), which can also be isolated in moderate yields. Complexes 1-3 were characterized by ultraviolet-visible (UV-vis) spectroscopy, and their solid-state structures were determined by X-ray crystallography. These complexes were further characterized via 1H NMR spectroscopy (in the case of 1 and 2) or EPR spectroscopy (in the case of 3). Irradiation of complexes 1 and 2 with 371 nm light generates the known dinitrosyl complexes, [MeLM(NO)2] (M = Co, 4; Fe, 5), along with Ph3CH and 9-phenylfluorene. We propose that 4 and 5 are formed via the putative hyponitrite intermediates, [MeLM(κ2-O,O-ONNO)], which are formed by photoinduced homolysis of the C-N bond of the [O2N2CPh3] ligand. In contrast, irradiation of complex 3 with 371 nm light, in the presence of 1 equiv of PPh3, led to the formation of the Cu(I) complexes, [MeLCu(PPh3)], [(ArNCMeC(NO)CMeNAr)Cu(PPh3)] (6), and [(ArNCMeC(NO)CMeNAr)Cu]2 (7), of which the latter two are products of γ-nitrosation of the β-diketiminiate ligand. Also formed in this transformation are Ph3CN(H)OCPh3, Ph3PO, and N2O, along with trace amounts of NO.
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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5
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Hayton TW, Humphrey SM, Cossairt BM, Brutchey RL. We Need to Talk about New Materials Characterization. Inorg Chem 2023; 62:13165-13167. [PMID: 37555817 DOI: 10.1021/acs.inorgchem.3c02524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Affiliation(s)
- Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Simon M Humphrey
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, Texas 78734-0165, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Richard L Brutchey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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6
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Hertler PR, Lewis RA, Wu G, Hayton TW. Measuring Metal-Metal Communication in a Series of Ketimide-Bridged [Fe 2] 6+ Complexes. Inorg Chem 2023; 62:11829-11836. [PMID: 37462407 DOI: 10.1021/acs.inorgchem.3c01109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Reaction of Fe(acac)3 with 3 equiv of Li[N═C(R)Ph] (R = Ph, tBu) results in the formation of the [Fe2]6+ complexes, [Fe2(μ-N═C(R)Ph)2(N═C(R)Ph)4] (R = Ph, 1; tBu, 2), in low to moderate yields. Reaction of FeCl2 with 6 equiv of Li(N═C13H8) (HN═C13H8 = 9-fluorenone imine) results in the formation of [Li(THF)2]2[Fe(N═C13H8)4] (3) in good yield. Subsequent oxidation of 3 with ca. 0.8 equiv of I2 generates the [Fe2]6+ complex, [Fe2(μ-N═C13H8)2(N═C13H8)4] (4), along with free fluorenyl ketazine. Complexes 1, 2, and 4 were characterized by 1H NMR spectroscopy, X-ray crystallography, 57Fe Mössbauer spectroscopy, and SQUID magnetometry. The Fe-Fe distances in 1, 2, and 4 range from 2.803(7) to 2.925(1) Å, indicating that no direct Fe-Fe interaction is present in these complexes. The 57Fe Mössbauer spectra for complexes 1, 2, and 4 are all consistent with the presence of symmetry-equivalent high-spin Fe3+ centers. Finally, all three complexes exhibit a similar degree of antiferromagnetic coupling between the metal centers (J = -26 to -30 cm-1), as ascertained by SQUID magnetometry.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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7
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Nguyen TH, Paul EL, Lukens WW, Hayton TW. Evaluating f-Orbital Participation in the U V═E Multiple Bonds of [U(E)(NR 2) 3] (E = O, NSiMe 3, NAd; R = SiMe 3). Inorg Chem 2023; 62:6447-6457. [PMID: 37053543 DOI: 10.1021/acs.inorgchem.3c00455] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The reaction of 1 equiv of 1-azidoadamantane with [UIII(NR2)3] (R = SiMe3) in Et2O results in the formation of [UV(NR2)3(NAd)] (1, Ad = 1-adamantyl) in good yields. The electronic structure of 1, as well as those of the related U(V) complexes, [UV(NR2)3(NSiMe3)] (2) and [UV(NR2)3(O)] (3), were analyzed with EPR spectroscopy, SQUID magnetometry, NIR-visible spectroscopy, and crystal field modeling. This analysis revealed that, within this series of complexes, the steric bulk of the E2- (E═O, NR) ligand is the most important factor in determining the electronic structure. In particular, the increasing steric bulk of this ligand, on moving from O2- to [NAd]2-, results in increasing U═E distances and E-U-Namide angles. These changes have two principal effects on the resulting electronic structure: (1) the increasing U═E distances decreases the energy of the fσ orbital, which is primarily σ* with respect to the U═E bond, and (2) the increasing E-U-Namide angles increases the energy of fδ, due to increasing antibonding interactions with the amide ligands. As a result of the latter change, the electronic ground state for complexes 1 and 2 is primarily fφ in character, whereas the ground state for complex 3 is primarily fδ.
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Affiliation(s)
- Thien H Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Edward L Paul
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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8
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Baeza Cinco MÁ, Chakraborty A, Guzman CF, Kräh S, Wu G, Hayton TW. NO and N 2O Release from the Trityl Diazeniumdiolate Complexes [M(O 2N 2CPh 3) 3] - (M = Fe, Co). Inorg Chem 2023; 62:4847-4852. [PMID: 36913615 DOI: 10.1021/acs.inorgchem.2c04088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Reaction of MBr2 with 3 equiv of [K(18-crown-6)][O2N2CPh3] generates the trityl diazeniumdiolate complexes [K(18-crown-6)][M(O2N2CPh3)3] (M = Co, 2; Fe, 3) in good yields. Irradiation of 2 and 3 using 371 nm light led to NO formation in 10 and 1% yields (calculated assuming a maximum of 6 equiv of NO produced per complex), respectively. N2O was also formed during the photolysis of 2, in 63% yield, whereas photolysis of 3 led to the formation of N2O, as well as Ph3CN(H)OCPh3, in 37 and 5% yields, respectively. These products are indicative of diazeniumdiolate fragmentation via both C-N and N-N bond cleavage pathways. In contrast, oxidation of complexes 2 and 3 with 1.2 equiv of [Ag(MeCN)4][PF6] led to N2O formation but no NO formation, suggesting that diazeniumdiolate fragmentation occurs exclusively via C-N bond cleavage under these conditions. While the photolytic yields of NO are modest, they represent a 10- to 100-fold increase compared to the previously reported Zn congener, suggesting that the presence of a redox-active metal center favors NO formation upon trityl diazeniumdiolate fragmentation.
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Arunavo Chakraborty
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Camilo F Guzman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Sabrina Kräh
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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9
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Ordoñez O, Yu X, Wu G, Autschbach J, Hayton TW. Assessing the 4f Orbital Participation in the Ln–C Bonds of [Li(THF) 4][Ln(C 6Cl 5) 4] (Ln = La, Ce). Inorg Chem 2022; 61:15138-15143. [DOI: 10.1021/acs.inorgchem.2c02304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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10
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Baeza Cinco MÁ, Kräh S, Guzman CF, Wu G, Hayton TW. Photolytic or Oxidative Fragmentation of Trityl Diazeniumdiolate (O 2N 2CPh 3-): Evidence for Both C-N and N-N Bond Cleavage. Inorg Chem 2022; 61:14924-14928. [PMID: 36098655 DOI: 10.1021/acs.inorgchem.2c01809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Exposure of [K(18-crown-6)(THF)2][CPh3] (THF = tetrahydrofuran; Ph = phenyl) to an atmosphere of nitric oxide (NO) cleanly generates [K(18-crown-6)][O2N2CPh3] (1) in excellent yields. A subsequent reaction of [ZnCl2(THF)2] with 3 equiv of 1 affords the C-diazeniumdiolate complex [K(18-crown-6)][Zn(O2N2CPh3)3] (2). Both 1 and 2 were characterized by 1H and 13C{1H} NMR spectroscopy, and their structures were confirmed by X-ray crystallography. Photolysis of 2 using 371 nm light resulted in the formation of three trityl-containing products, namely, Ph3CH, 9-phenylfluorene, and Ph3CN(H)OCPh3 (3). In addition, we detected nitrous oxide (N2O), as well as small amounts of NO in the reaction mixture. In contrast, oxidation of 2 with 1.2 equiv of [Ag(MeCN)4][PF6] resulted in the formation of O(CPh3)2 as the major trityl-containing product; N2O was also detected in the reaction mixture, but NO was not apparently formed in this case. The observation of these fragmentation products indicates that the [O2N2CPh3]- ligand is susceptible to both C-N bond and N-N bond cleavage. Moreover, the different product distributions suggest that [O2N2CPh3]- is susceptible to different modes of fragmentation.
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Sabrina Kräh
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Camilo F Guzman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
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11
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Baeza Cinco MÁ, Wu G, Telser J, Hayton TW. Structural and Spectroscopic Characterization of a Zinc-Bound N-Oxyphthalimide Radical. Inorg Chem 2022; 61:13250-13255. [PMID: 35972238 DOI: 10.1021/acs.inorgchem.2c01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thermolysis of a 1:1:1 mixture of MeLH (MeL = {(2,6-iPr2C6H3)NC(Me)}2CH), N-hydroxyphthalimide (HOPth), and diethylzinc in toluene at 77 °C provided [MeLZn(OPth)] (1) in good yield after workup. The subsequent reduction of 1 with 1.3 equiv of KC8 and 1 equiv of 2.2.2-cryptand, in tetrahydrofuran, provided [K(2.2.2-cryptand)][MeLZn(OPth)] (2) in 74% yield after workup. Characterization of 2 via X-ray crystallography and electron paramagnetic resonance spectroscopy reveals the presence of an S = 1/2 radical on the N-oxyphthalimide ligand. Importantly, these data represent the first structural and spectroscopic confirmation of the redox activity of a metal-bound N-oxyphthalimide fragment, expanding the range of structurally characterized redox-active ligands.
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, 430 South Michigan Avenue. Chicago, Illinois 60605-1394, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
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12
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Hertler PR, Kautzsch L, Touchton AJ, Wu G, Hayton TW. Metal-Metal-Bonded Fe 4 Clusters with Slow Magnetic Relaxation. Inorg Chem 2022; 61:9997-10005. [PMID: 35709487 DOI: 10.1021/acs.inorgchem.2c00865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of FeBr2 with Li(N═CtBu2) (0.5 equiv) and Zn0 (2 equiv) results in the formation of the formally mixed-valent cluster [Fe4Br2(N═CtBu2)4] (1) in moderate yield. The subsequent reaction of 1 with Na(N═CtBu2) results in formation of [Fe4Br(N═CtBu2)5] (2), also in moderate yield. Both 1 and 2 were characterized by zero-field 57Fe Mössbauer spectroscopy, X-ray crystallography, and superconducting quantum interference device magnetometry. Their tetrahedral [Fe4]6+ cores feature short Fe-Fe interactions (ca. 2.50 Å). Additionally, both 1 and 2 display S = 7 ground states at room temperature and slow magnetic relaxation with zero-field relaxation barriers of Ueff = 14.7(4) and 15.6(7) cm-1, respectively. Moreover, AC magnetic susceptibility measurements were well modeled by assuming an Orbach relaxation process.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Linus Kautzsch
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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13
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Hayton TW, Shafaat HS. Periodic TableTalks: An Oasis of Science within a Conference Desert. Inorg Chem 2022; 61:5965-5971. [DOI: 10.1021/acs.inorgchem.2c01108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Hannah S. Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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14
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Keener M, Mattejat M, Zheng SL, Wu G, Hayton TW, Ménard G. Selective electrochemical capture and release of uranyl from aqueous alkali, lanthanide, and actinide mixtures using redox-switchable carboranes. Chem Sci 2022; 13:3369-3374. [PMID: 35432881 PMCID: PMC8943888 DOI: 10.1039/d1sc07070c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 02/20/2022] [Indexed: 11/29/2022] Open
Abstract
We report the selective electrochemical biphasic capture of the uranyl cation (UO22+) from mixed-metal alkali (Cs+), lanthanide (Nd3+, Sm3+), and actinide (Th4+, UO22+) aqueous solutions to an organic, 1,2-dichloroethane (DCE), phase using the ortho-substituted nido-carborane anion, [1,2-(Ph2PO)2-1,2-C2B10H10]2− (POCb2−). The reduced POCb2− is generated by electrochemical reduction of the closo-carborane, POCb, prior to mixing with the aqueous mixed-metal solution. Subsequent UO22+ release from the captured product, [UO2(POCb)2]2−, was performed by galvanostatic bulk electrolysis of the DCE phase and back-extraction of UO22+ to a fresh aqueous phase. The selective capture and release of UO22+ was confirmed by combined ICP-OES and NMR spectral analyses of the aqueous and organic phases, respectively, against the newly synthesized nido-carborane complexes, [[CoCp*2][Cs(POCb)]]2, [CoCp*2]3[Nd(POCb)3], [CoCp*2]3[Sm(POCb)3], and [CoCp*2]2[Th(POCb)3]. Redox-switchable carboranes electrochemically capture and release UO22+ selectively from mixed metal aqueous solutions, mimicking in part spent nuclear fuel.![]()
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Affiliation(s)
- Megan Keener
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Maxwell Mattejat
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University Cambridge Massachusetts 02138 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Gabriel Ménard
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
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Kent G, Yu X, Wu G, Autschbach J, Hayton TW. Ring-opening of a Thorium Cyclopropenyl Complex Generates a Transient Thorium-bound Carbene. Chem Commun (Camb) 2022; 58:6805-6808. [DOI: 10.1039/d2cc01780f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of [Cp3ThCl] with in situ generated lithium-3,3-diphenylcyclopropene results in the formation of [Cp3Th(3,3-diphenylcyclopropenyl)] (1), in good yields. Thermolysis of 1 results in isomerization to the ring-opened product, [Cp3Th(3-phenyl-1H-inden-1-yl)]...
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16
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Touchton AJ, Wu G, Hayton TW. [Ni 30S 16(PEt 3) 11]: An Open-shell Nickel Sulfide Nanocluster with a “Metal-like” Core. Chem Sci 2022; 13:5171-5175. [PMID: 35655571 PMCID: PMC9093199 DOI: 10.1039/d2sc00960a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/08/2022] [Indexed: 11/21/2022] Open
Abstract
Reaction of [Ni(1,5-cod)2] (30 equiv.) with PEt3 (46 equiv.) and S8 (1.9 equiv.) in toluene, followed by heating at 115 °C for 16 h, results in the formation of the atomically precise nanocluster (APNC), [Ni30S16(PEt3)11] (1), in 14% isolated yield. Complex 1 represents the largest open-shell Ni APNC yet isolated. In the solid state, 1 features a compact “metal-like” core indicative of a high degree of Ni–Ni bonding. Additionally, SQUID magnetometry suggests that 1 possesses a manifold of closely-spaced electronic states near the HOMO–LUMO gap. In situ monitoring by ESI-MS and 31P{1H} NMR spectroscopy reveal that 1 forms via the intermediacy of smaller APNCs, including [Ni8S5(PEt3)7] and [Ni26S14(PEt3)10] (2). The latter APNC was also characterized by X-ray crystallography and features a nearly identical core structure to that found in 1. This work demonstrates that large APNCs with a high degree of metal–metal bonding are isolable for nickel, and not just the noble metals. The atomically-precise nanocluster, [Ni30S16(PEt3)11], features a compact “metal-like” core indicative of a high degree of Ni–Ni bonding, along with an open-shell ground state.![]()
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Affiliation(s)
- Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
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17
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Staun SL, Wu G, Lukens WW, Hayton TW. Synthesis of a heterobimetallic actinide nitride and an analysis of its bonding. Chem Sci 2021; 12:15519-15527. [PMID: 35003580 PMCID: PMC8653994 DOI: 10.1039/d1sc05072a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/13/2021] [Indexed: 11/21/2022] Open
Abstract
Reaction of [K(DME)][Th{N(R)(SiMe2 CH2)}2(NR2)] (R = SiMe3) with 1 equiv. of [U(NR2)3(NH2)] (1) in THF, in the presence of 18-crown-6, results in formation of a bridged uranium-thorium nitride complex, [K(18-crown-6)(THF)2][(NR2)3UIV(μ-N)ThIV(NR2)3] (2), which can be isolated in 48% yield after work-up. Complex 2 is the first isolable molecular mixed-actinide nitride complex. Also formed in the reaction is the methylene-bridged mixed-actinide nitride, [K(18-crown-6)][K(18-crown-6)(Et2O)2][(NR2)2U(μ-N)(μ-κ2-C,N-CH2SiMe2NR)Th(NR2)2]2 (3), which can be isolated in 34% yield after work-up. Complex 3 is likely generated by deprotonation of a methyl group in 2 by [NR2]-, yielding the new μ-CH2 moiety and HNR2. Reaction of 2 with 0.5 equiv. of I2 results in formation of a UV/ThIV bridged nitride, [(NR2)3UV(μ-N)ThIV(NR2)3] (4), which can be isolated in 42% yield after work-up. The electronic structure of 4 was analyzed with EPR spectroscopy, SQUID magnetometry, and NIR-visible spectroscopy. This analysis demonstrated that the energies of 5f orbitals of 4 are largely determined by the strong ligand field exerted by the nitride ligand.
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Affiliation(s)
- Selena L Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
| | - Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
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18
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Abstract
The reaction of [Ni(1,5-COD)2] (1.0 equiv), PEt3 (0.04 equiv), SePEt3 (0.52 equiv), and [NiCl2(PEt3)2] (0.07 equiv) in a mixture of toluene and THF results in the formation of [Ni23Se12Cl3(PEt3)10] (1), which can be isolated in moderate yield after workup. Complex 1 was characterized by NMR spectroscopy, ESI-MS, and X-ray crystallography. This open-shell nanocluster features a central [Ni13]7+ anticuboctahedral kernel, which is encapsulated by a [Ni10(μ-Se)9Cl3]- shell, along with ten PEt3 ligands and three (μ4-Se)2- ligands. On the basis of our spectroscopic and crystallographic analysis, coupled with in situ spectroscopic monitoring, we believe that the previously reported nanocluster, [Ni23Se12(PEt3)13], is actually better formulated as [Ni23Se12Cl3(PEt3)10].
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Affiliation(s)
- Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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19
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Affiliation(s)
- Alexander J. Touchton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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20
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Kent GT, Yu X, Wu G, Autschbach J, Hayton TW. Synthesis and electronic structure analysis of the actinide allenylidenes, [{(NR 2) 3}An(CCCPh 2)] - (An = U, Th; R = SiMe 3). Chem Sci 2021; 12:14383-14388. [PMID: 34880989 PMCID: PMC8580070 DOI: 10.1039/d1sc04666g] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/02/2021] [Indexed: 11/26/2022] Open
Abstract
The reaction of [AnCl(NR2)3] (An = U, Th, R = SiMe3) with in situ generated lithium-3,3-diphenylcyclopropene results in the formation of [{(NR2)3}An(CH[double bond, length as m-dash]C[double bond, length as m-dash]CPh2)] (An = U, 1; Th, 2) in good yields after work-up. Deprotonation of 1 or 2 with LDA/2.2.2-cryptand results in formation of the anionic allenylidenes, [Li(2.2.2-cryptand)][{(NR2)3}An(CCCPh2)] (An = U, 3; Th, 4). The calculated 13C NMR chemical shifts of the Cα, Cβ, and Cγ nuclei in 2 and 4 nicely reproduce the experimentally assigned order, and exhibit a characteristic spin-orbit induced downfield shift at Cα due to involvement of the 5f orbitals in the Th-C bonds. Additionally, the bonding analyses for 3 and 4 show a delocalized multi-center character of the ligand π orbitals involving the actinide. While a single-triple-single-bond resonance structure (e.g., An-C[triple bond, length as m-dash]C-CPh2) predominates, the An[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]CPh2 resonance form contributes, as well, more so for 3 than for 4.
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Affiliation(s)
- Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York Buffalo NY 14260 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York Buffalo NY 14260 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
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21
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Kent GT, Yu X, Pauly C, Wu G, Autschbach J, Hayton TW. Synthesis of Parent Acetylide and Dicarbide Complexes of Thorium and Uranium and an Examination of Their Electronic Structures. Inorg Chem 2021; 60:15413-15420. [PMID: 34585570 DOI: 10.1021/acs.inorgchem.1c02064] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reaction of [AnCl(NR2)3] (An = U or Th; R = SiMe3) with NaCCH and tetramethylethylenediamine (TMEDA) results in the formation of [An(C≡CH)(NR2)3] (1, An = U; 2, An = Th), which can be isolated in good yields after workup. Similarly, the reaction of 3 equiv of NaCCH and TMEDA with [AnCl(NR2)3] results in the formation of [Na(TMEDA)][An(C≡CH)2(NR2)3] (4, An = U; 5, An = Th), which can be isolated in fair yields after workup. The reaction of 1 with 2 equiv of KC8 and 1 equiv of 2.2.2-cryptand in tetrahydrofuran results in formation of the uranium(III) acetylide complex [K(2.2.2-cryptand)][U(C≡CH)(NR2)3] (3). Thermolysis of 1 or 2 results in formation of the bimetallic dicarbide complexes [{An(NR2)3}2(μ,η1:η1-C2)] (6, An = U; 7, An = Th), whereas the reaction of 1 with [Th{N(R)(SiMe2CH2)}(NR2)2] results in the formation of [U(NR2)3(μ,η1:η1-C2)Th(NR2)3] (8). The 13C NMR chemical shifts of the α-acetylide carbon atoms in 2, 5, and 7 exhibit a characteristic spin-orbit-induced downfield shift, due to participation of the 5f orbitals in the Th-C bonds. Magnetism measurements demonstrate that 6 displays weak ferromagnetic coupling between the uranium(IV) centers (J = 1.78 cm-1).
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Affiliation(s)
- Greggory T Kent
- Department of Chemistry and Biochemistry, University of California-Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Christophe Pauly
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 40, Münster 48149, Germany
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California-Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California-Santa Barbara, Santa Barbara, California 93106, United States
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Affiliation(s)
- Selena L. Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Greggory T. Kent
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Alejandra Gomez-Torres
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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23
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Abstract
The reaction of AnCl4(DME)n (An = Th, n = 2; U, n = 0) with 5 equiv of LiC6Cl5 in Et2O resulted in the formation of homoleptic actinide-aryl "ate" complexes [Li(DME)2(Et2O)]2[Li(DME)2][Th(C6Cl5)5]3 ([Li][1]) and [Li(Et2O)4][U(C6Cl5)5] ([Li][2]). Similarly, the reaction of AnCl4(DME)n (An = Th, n = 2; U, n = 0) with 3 equiv of LiC6Cl5 in Et2O resulted in the formation of heteroleptic actinide-aryl "ate" complexes [Li(DME)2(Et2O)][Li(Et2O)2][ThCl3(C6Cl5)3] ([Li][3]) and [Li(Et2O)3][UCl2(C6Cl5)3] ([Li][4]). Density functional calculations show that the An-Cipso σ-bonds are considerably more covalent for the uranium complexes vs the thorium analogues, in line with past results. Additionally, good agreement between experiment and calculations is obtained for the 13Cipso NMR chemical shifts in [Li][1] and [Li][3]. The calculations demonstrate a deshielding by ca. 29 ppm from spin-orbit coupling effects originating at Th, which is a direct consequence of 5f orbital participation in the Th-C bonds.
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Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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Touchton AJ, Wu G, Hayton TW. Understanding the Early Stages of Nickel Sulfide Nanocluster Growth: Isolation of Ni 3 , Ni 4 , Ni 5 , and Ni 8 Intermediates. Small 2021; 17:e2003133. [PMID: 32954670 DOI: 10.1002/smll.202003133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/05/2020] [Indexed: 06/11/2023]
Abstract
Addition of sub-stoichiometric quantities of PEt3 and diphenyl disulfide to a solution of [Ni(1,5-cod)2 ] generates a mixture of [Ni3 (SPh)4 (PEt3 )3 ] (1), unreacted [Ni(1,5-cod)2 ], and [(1,5-cod)Ni(PEt3 )2 ], according to 1 H and 31 P{1 H} NMR spectroscopic monitoring of the in situ reaction mixture. On standing, complex 1 converts into [Ni4 (S)(Ph)(SPh)3 (PEt3 )3 ] (2), via formal addition of a "Ni(0)" equivalent, coupled with a CS oxidative addition step, which simultaneously generates the Ni-bound phenyl ligand and the μ3 -sulfide ligand. Upon gentle heating, complex 2 converts into a mixture of [Ni5 (S)2 (SPh)2 (PEt3 )5 ] (3) and [Ni8 (S)5 (PEt3 )7 ] (4), via further addition of "Ni(0)" equivalents, in combination with a series of C-S oxidative addition and CC reductive elimination steps, which serve to convert thiophenolate ligands into sulfide ligands and biphenyl. The presence of 1-4 in the reaction mixture is confirmed by their independent syntheses and subsequent spectroscopic characterization. Overall, this work provides an unprecedented level of detail of the early stages of Ni nanocluster growth and highlights the fundamental reaction steps (i.e., metal atom addition, CS oxidative addition, and CC reductive elimination) that are required to grow an individual cluster.
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Affiliation(s)
- Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
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25
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Abstract
The reaction of 1.75 equiv of tBuNC with Ni(1,5-COD)2, followed by crystallization from benzene/pentane, resulted in the isolation of [Ni8(CNtBu)12][Cl] (2) in low yields. Similarly, the reaction of Ni(1,5-COD)2 with 0.6 equiv of [Ni(CNtBu)4], followed by addition of 0.08 equiv of I2, resulted in the formation of [Ni8(CNtBu)12][I] (3), which could be isolated in 52% yield after work-up. Both 2 and 3 adopt folded nanosheet structures in the solid state, characterized by two symmetry-related planar Ni4 arrays, six terminally bound tBuNC ligands, and six tBuNC ligands that adopt bridging coordination modes. The metrical parameters of the six bridging tBuNC ligands suggest that they have been reduced to their [tBuNC]2- form. In contrast to the nanosheet structures observed for 2 and 3, gas phase Ni8 is predicted to feature a compact bisdisphenoid ground state structure. The strikingly different structural outcomes reveal the profound structural changes that can occur upon addition of ligands to bare metal clusters. Ultimately, the characterization of 2 and 3 will enable more accurate structural predictions of ligand-protected nanoclusters in the future.
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Affiliation(s)
- Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106-9510, USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106-9510, USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106-9510, USA
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26
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Kent GT, Cook AW, Damon PL, Lewis RA, Wu G, Hayton TW. Synthesis and Characterization of Two "Tied-Back" Lithium Ketimides and Isolation of a Ketimide-Bridged [Cr 2] 6+ Dimer with Strong Antiferromagnetic Coupling. Inorg Chem 2021; 60:4996-5004. [PMID: 33764048 DOI: 10.1021/acs.inorgchem.1c00052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of 1 equiv of KN(SiMe3)2 with 9-fluorenone results in the formation of (Me3Si)N═C13H8 (1) in high yield after work-up. Addition of 1 equiv of phenol to 1 results in rapid desilylation and formation of 9-fluorenone imine, HN═C13H8 (2). Subsequent reaction of 2 with 1 equiv of LiNiPr2 results in deprotonation and formation of [Li(Et2O)]4[N═C13H8]4 (3) in good yield. Reaction of 1 equiv of KN(SiMe3)2 with 2-adamantanone for 7 days at room temperature results in the formation of (Me3Si)N═C10H14 (4) in good yield. Dissolution of 4 in neat MeOH results in rapid desilylation concomitant with formation of 2-adamantanone imine, HN═C10H14 (5). Subsequent reaction of 5 with 1 equiv of LiNiPr2 results in formation of [Li(THF)]4[N═C10H14]4 (6). Both 3 and 6 were characterized by X-ray crystallography. Finally, reaction of CrCl3 with 3.5 equiv of 6 results in formation of the [Cr2]6+ dimer, [Li][Cr2(N═C10H14)7] (7), which can be isolated in modest yield after work-up. Complex 7 features a Cr-Cr bond length of 2.653(2) Å. Additionally, solid-state magnetic susceptibility measurements reveal strong antiferromagnetic coupling between the two Cr centers, with J = -200 cm-1.
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Affiliation(s)
- Greggory T Kent
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrew W Cook
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Peter L Damon
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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Ordoñez O, Yu X, Wu G, Autschbach J, Hayton TW. Cover Feature: Synthesis and Characterization of Two Uranyl‐Aryl “Ate” Complexes (Chem. Eur. J. 19/2021). Chemistry 2021. [DOI: 10.1002/chem.202100128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Xiaojuan Yu
- Department of Chemistry University at Buffalo State University of New York Buffalo NY 14260 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Jochen Autschbach
- Department of Chemistry University at Buffalo State University of New York Buffalo NY 14260 USA
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry University of California Santa Barbara Santa Barbara CA 93106 USA
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28
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Abstract
Reaction of [UO2 Cl2 (THF)3 ] with 3 equivalents of LiC6 Cl5 in Et2 O resulted in the formation of first uranyl aryl complex [Li(Et2 O)2 (THF)][UO2 (C6 Cl5 )3 ] ([Li][1]) in good yields. Subsequent dissolution of [Li][1] in THF resulted in conversion into [Li(THF)4 ][UO2 (C6 Cl5 )3 (THF)] ([Li][2]), also in good yields. DFT calculations reveal that the U-C bonds in [Li][1] and [Li][2] exhibit appreciable covalency. Additionally, the 13 C NMR chemical shifts for their Cipso environments are strongly affected by spin-orbit coupling-a consequence of 5f orbital participation in the U-C bonds.
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Affiliation(s)
- Osvaldo Ordoñez
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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29
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Staun SL, Stevens LM, Smiles DE, Goodwin CAP, Billow BS, Scott BL, Wu G, Tondreau AM, Gaunt AJ, Hayton TW. Expanding the Nonaqueous Chemistry of Neptunium: Synthesis and Structural Characterization of [Np(NR 2) 3Cl], [Np(NR 2) 3Cl] -, and [Np{ N(R)(SiMe 2CH 2)} 2(NR 2)] - (R = SiMe 3). Inorg Chem 2021; 60:2740-2748. [PMID: 33539075 DOI: 10.1021/acs.inorgchem.0c03616] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Reaction of 3 equiv of NaNR2 (R = SiMe3) with NpCl4(DME)2 in THF afforded the Np(IV) silylamide complex, [Np(NR2)3Cl] (1), in good yield. Reaction of 1 with 1.5 equiv of KC8 in THF, in the presence of 1 equiv of dibenzo-18-crown-6, resulted in formation of [{K(DB-18-C-6)(THF)}3(μ3-Cl)][Np(NR2)3Cl]2 (4), also in good yield. Complex 4 represents the first structurally characterized Np(III) amide. Finally, reaction of NpCl4(DME)2 with 5 equiv of NaNR2 and 1 equiv of dibenzo-18-crown-6 afforded the Np(IV) bis(metallacycle), [{Na(DB-18-C-6)(Et2O)0.62(κ1-DME)0.38}2(μ-DME)][Np{N(R)(SiMe2CH2)}2(NR2)]2 (8), in moderate yield. Complex 8 was characterized by 1H NMR spectroscopy and X-ray crystallography and represents a rare example of a structurally characterized neptunium-hydrocarbyl complex. To support these studies, we also synthesized the uranium analogues of 4 and 8, namely, [K(2,2,2-cryptand)][U(NR2)3Cl] (2), [K(DB-18-C-6)(THF)2][U(NR2)3Cl] (3), [Na(DME)3][U{N(R)(SiMe2CH2)}2(NR2)] (6), and [{Na(DB-18-C-6)(Et2O)0.5(κ1-DME)0.5}2(μ-DME)][U{N(R)(SiMe2CH2)}2(NR2)]2 (7). Complexes 2, 3, 6, and 7 were characterized by a number of techniques, including NMR spectroscopy and X-ray crystallography.
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Affiliation(s)
- Selena L Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States.,Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Lauren M Stevens
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Danil E Smiles
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States.,Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Conrad A P Goodwin
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Brennan S Billow
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Brian L Scott
- Materials and Physics Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Aaron M Tondreau
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Andrew J Gaunt
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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30
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Affiliation(s)
- Miguel Á. Baeza Cinco
- Department of Chemistry and Biochemistry University of California Santa Barbara 93106 Santa Barbara CA USA
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry University of California Santa Barbara 93106 Santa Barbara CA USA
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Affiliation(s)
- Greggory T. Kent
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Selena L. Staun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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Sergentu DC, Kent GT, Staun SL, Yu X, Cho H, Autschbach J, Hayton TW. Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State 15N NMR Spectroscopy. Inorg Chem 2020; 59:10138-10145. [DOI: 10.1021/acs.inorgchem.0c01263] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Dumitru-Claudiu Sergentu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Greggory T. Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Selena L. Staun
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Herman Cho
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 908 Battelle Boulevard, Richland, Washington 99354, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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Abstract
Reaction of [Li(THF)]4[L] (L = Me8-calix[4]pyrrole]) with 0.5 equiv of [UVIO2Cl2(THF)2]2 results in formation of the oxidized calix[4]pyrrole product, [Li(THF)]2[LΔ] (1), concomitant with formation of reduced uranium oxide byproducts. Complex 1 can also be generated by reaction of [Li(THF)]4[L] with 1 equiv of I2. We hypothesize that formation of 1 proceeds via formation of a highly oxidizing cis-uranyl intermediate, [Li]2[cis-UVIO2(calix[4]pyrrole)]. To test this hypothesis, we explored the reaction of 1 with either 0.5 equiv of [UVIO2Cl2(THF)2]2 or 1 equiv of [UVIO2(OTf)2(THF)3], which affords the isostructural uranyl complexes, [Li(THF)][UVIO2(LΔ)Cl(THF)] (2) and [Li(THF)][UVIO2(LΔ)(OTf)(THF)] (3), respectively. In the solid state, 2 and 3 feature unprecedented uranyl-η5-pyrrole interactions, making them rare examples of uranyl organometallic complexes. In addition, 2 and 3 exhibit some of the smallest O-U-O angles reported to date (2: 162.0(7) and 162.7(7)°; 3: 164.5(5)°). Importantly, the O-U-O bending observed in these complexes suggests that the oxidation of [Li(THF)]4[L] does indeed occur via an unobserved cis-uranyl intermediate.
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Affiliation(s)
- Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Jesse Murillo
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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Baeza Cinco MÁ, Wu G, Kaltsoyannis N, Hayton TW. Synthesis of a "Masked" Terminal Zinc Sulfide and Its Reactivity with Brønsted and Lewis Acids. Angew Chem Int Ed Engl 2020; 59:8947-8951. [PMID: 32196886 DOI: 10.1002/anie.202002364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Indexed: 11/05/2022]
Abstract
The "masked" terminal Zn sulfide, [K(2.2.2-cryptand)][Me LZn(S)] (2) (Me L={(2,6-i Pr2 C6 H3 )NC(Me)}2 CH), was isolated via reaction of [Me LZnSCPh3 ] (1) with 2.3 equivalents of KC8 in THF, in the presence of 2.2.2-cryptand, at -78 °C. Complex 2 reacts readily with PhCCH and N2 O to form [K(2.2.2-cryptand)][Me LZn(SH)(CCPh)] (4) and [K(2.2.2-cryptand)][Me LZn(SNNO)] (5), respectively, displaying both Brønsted and Lewis basicity. In addition, the electronic structure of 2 was examined computationally and compared with the previously reported Ni congener, [K(2.2.2-cryptand)][tBu LNi(S)] (tBu L={(2,6-i Pr2 C6 H3 )NC(t Bu)}2 CH).
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93016, USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93016, USA
| | - Nikolas Kaltsoyannis
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93016, USA
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35
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Baeza Cinco MÁ, Wu G, Kaltsoyannis N, Hayton TW. Synthesis of a “Masked” Terminal Zinc Sulfide and Its Reactivity with Brønsted and Lewis Acids. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Miguel Á. Baeza Cinco
- Department of Chemistry and Biochemistry University of California, Santa Barbara Santa Barbara CA 93016 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry University of California, Santa Barbara Santa Barbara CA 93016 USA
| | - Nikolas Kaltsoyannis
- Department of Chemistry University of Manchester Oxford Road Manchester M13 9PL UK
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry University of California, Santa Barbara Santa Barbara CA 93016 USA
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36
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Cook AW, Bocarsly JD, Lewis RA, Touchton AJ, Morochnik S, Hayton TW. An iron ketimide single-molecule magnet [Fe 4(N[double bond, length as m-dash]CPh 2) 6] with suppressed through-barrier relaxation. Chem Sci 2020; 11:4753-4757. [PMID: 34122931 PMCID: PMC8159258 DOI: 10.1039/d0sc01578d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Reaction of FeBr2 with 1.5 equiv. of LiN[double bond, length as m-dash]CPh2 and 2 equiv. of Zn, in THF, results in the formation of the tetrametallic iron ketimide cluster [Fe4(N[double bond, length as m-dash]CPh2)6] (1) in moderate yield. Formally, two Fe centers in 1 are Fe(i) and two are Fe(ii); however, Mössbauer spectroscopy and SQUID magnetometry suggests that the [Fe4]6+ core of 1 exhibits complete valence electron delocalization, with a thermally-persistent spin ground state of S = 7. AC and DC SQUID magnetometry reveals the presence of slow magnetic relaxation in 1, indicative of single-molecule magnetic (SMM) behaviour with a relaxation barrier of U eff = 29 cm-1. Remarkably, very little quantum tunnelling or Raman relaxation is observed down to 1.8 K, which leads to an open hysteresis loop and long relaxation times (up to 34 s at 1.8 K and zero field and 440 s at 1.67 kOe). These results suggest that transition metal ketimide clusters represent a promising avenue to create long-lifetime single molecule magnets.
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Affiliation(s)
- Andrew W Cook
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Joshua D Bocarsly
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara Santa Barbara California 93106 USA
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Simona Morochnik
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106 USA
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37
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Affiliation(s)
- Mikiyas K. Assefa
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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38
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Affiliation(s)
- Alexander J. Touchton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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39
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Lukens WW, Edelstein NM, Magnani N, Hayton TW, Fortier S, Seaman LA. Correction to “Quantifying the σ and π Interactions between U(V) f Orbitals and Halide, Alkyl, Alkoxide, Amide and Ketimide Ligands”. J Am Chem Soc 2020; 142:5442-5445. [DOI: 10.1021/jacs.0c02284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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40
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Keener M, Hunt C, Carroll TG, Kampel V, Dobrovetsky R, Hayton TW, Ménard G. Redox-switchable carboranes for uranium capture and release. Nature 2020; 577:652-655. [DOI: 10.1038/s41586-019-1926-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 10/30/2019] [Indexed: 11/09/2022]
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41
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Affiliation(s)
- Andrew W. Cook
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Peter Hrobárik
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, SK-84215 Bratislava, Slovakia
| | - Peter L. Damon
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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42
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Cook AW, Hrobárik P, Damon PL, Najera D, Horváth B, Wu G, Hayton TW. Synthesis and Characterization of a Linear, Two-Coordinate Pt(II) Ketimide Complex. Inorg Chem 2019; 58:15927-15935. [DOI: 10.1021/acs.inorgchem.9b02443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Andrew W. Cook
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Peter Hrobárik
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, SK-84215 Bratislava, Slovakia
| | - Peter L. Damon
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Daniel Najera
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Branislav Horváth
- Central NMR Laboratory, Faculty of Pharmacy, Comenius University, SK-83232 Bratislava, Slovakia
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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43
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Gladfelder JJ, Ghosh S, Podunavac M, Cook AW, Ma Y, Woltornist RA, Keresztes I, Hayton TW, Collum DB, Zakarian A. Enantioselective Alkylation of 2-Alkylpyridines Controlled by Organolithium Aggregation. J Am Chem Soc 2019; 141:15024-15028. [PMID: 31460756 DOI: 10.1021/jacs.9b08659] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Direct enantioselective α-alkylation of 2-alkylpyridines provides access to chiral pyridines via an operationally simple protocol that obviates the need for prefunctionalization or preactivation of the substrate. The alkylation is accomplished using chiral lithium amides as noncovalent stereodirecting auxiliaries. Crystallographic and solution NMR studies provide insight into the structure of well-defined chiral aggregates in which a lithium amide reagent directs asymmetric alkylation.
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Affiliation(s)
- Joshua J Gladfelder
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Santanu Ghosh
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Maša Podunavac
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Andrew W Cook
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Yun Ma
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Ryan A Woltornist
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Ivan Keresztes
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - David B Collum
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Armen Zakarian
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
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44
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Assefa MK, Sergentu DC, Seaman LA, Wu G, Autschbach J, Hayton TW. Synthesis, Characterization, and Electrochemistry of the Homoleptic f Element Ketimide Complexes [Li]2[M(N═CtBuPh)6] (M = Ce, Th). Inorg Chem 2019; 58:12654-12661. [DOI: 10.1021/acs.inorgchem.9b01428] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Mikiyas K. Assefa
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
| | - Dumitru-Claudiu Sergentu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
| | - Lani A. Seaman
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
| | - Jochen Autschbach
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, 93106 Santa Barbara, California, United States
- Department of Chemistry, University at Buffalo, State University of New York, 14260 Buffalo, New York, United States
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45
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Cook AW, Jones ZR, Wu G, Teat SJ, Scott SL, Hayton TW. Synthesis and Characterization of “Atlas-Sphere” Copper Nanoclusters: New Insights into the Reaction of Cu2+ with Thiols. Inorg Chem 2019; 58:8739-8749. [DOI: 10.1021/acs.inorgchem.9b01140] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Simon J. Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Kent GT, Wu G, Hayton TW. Synthesis and Crystallographic Characterization of the Tetravalent Actinide-DOTA Complexes [AnIV(κ8-DOTA)(DMSO)] (An = Th, U). Inorg Chem 2019; 58:8253-8256. [DOI: 10.1021/acs.inorgchem.9b00736] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Greggory T. Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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47
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Staun SL, Sergentu DC, Wu G, Autschbach J, Hayton TW. Use of 15N NMR spectroscopy to probe covalency in a thorium nitride. Chem Sci 2019; 10:6431-6436. [PMID: 31367305 PMCID: PMC6615217 DOI: 10.1039/c9sc01960j] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 06/02/2019] [Indexed: 01/29/2023] Open
Abstract
The first isolable molecular thorium nitride, [(NR2)3Th(μ-N)Th(NR2)3]–, was synthesized by reaction of [Th{N(R)(SiMe2)CH2}(NR2)2] with NaNH2 and characterized by X-ray crystallography, 15N NMR spectroscopy, and DFT calculations.
Reaction of the thorium metallacycle, [Th{N(R)(SiMe2)CH2}(NR2)2] (R = SiMe3) with 1 equiv. of NaNH2 in THF, in the presence of 18-crown-6, results in formation of the bridged thorium nitride complex, [Na(18-crown-6)(Et2O)][(R2N)3Th(μ-N)(Th(NR2)3] ([Na][1]), which can be isolated in 66% yield after work-up. Complex [Na][1] is the first isolable molecular thorium nitride complex. Mechanistic studies suggest that the first step of the reaction is deprotonation of [Th{N(R)(SiMe2)CH2}(NR2)2] by NaNH2, which results in formation of the thorium bis(metallacycle) complex, [Na(THF)x][Th{N(R)(SiMe2CH2)}2(NR2)], and NH3. NH3 then reacts with unreacted [Th{N(R)(SiMe2)CH2}(NR2)2], forming [Th(NR2)3(NH2)] (2), which protonates [Na(THF)x][Th{N(R)(SiMe2CH2)}2(NR2)] to give [Na][1]. Consistent with hypothesis, addition of excess NH3 to a THF solution of [Th{N(R)(SiMe2)CH2}(NR2)2] results in formation of [Th(NR2)3(NH2)] (2), which can be isolated in 51% yield after work-up. Furthermore, reaction of [K(DME)][Th{N(R)(SiMe2CH2)}2(NR2)] with 2, in THF-d8, results in clean formation of [K][1], according to 1H NMR spectroscopy. The electronic structures of [1]– and 2 were investigated by 15N NMR spectroscopy and DFT calculations. This analysis reveals that the Th–Nnitride bond in [1]– features more covalency and a greater degree of bond multiplicity than the Th–NH2 bond in 2. Similarly, our analysis indicates a greater degree of covalency in [1]–vs. comparable thorium imido and oxo complexes.
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Affiliation(s)
- Selena L Staun
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , USA .
| | - Dumitru-Claudiu Sergentu
- Department of Chemistry , University at Buffalo , State University of New York , 312 Natural Sciences Complex , Buffalo , NY 14260-3000 , USA .
| | - Guang Wu
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , USA .
| | - Jochen Autschbach
- Department of Chemistry , University at Buffalo , State University of New York , 312 Natural Sciences Complex , Buffalo , NY 14260-3000 , USA .
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , USA .
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Abstract
Atomically precise nanoclusters (APNCs) are an emerging area of nanoscience. Their monodispersity and well-defined arrangement of capping ligands facilitates the interrogation of their fundamental physical properties, allowing for the development of structure-function relationships, as well as their optimization for a variety of applications, including quantum computing, solid-state memory, catalysis, sensing, and imaging. However, APNCs present several unique synthetic and characterization challenges. For example, nanocluster syntheses are infamously low yielding and often generate complicated mixtures. This combination of factors makes nanocluster purification and characterization more difficult than that of typical inorganic or organometallic complexes. Yet, while this fact is undoubtedly true, the past lessons learned from the characterization of inorganic complexes are still useful today. In this Account, we discuss six case studies taken from the recent literature in an attempt to identify common challenges and pitfalls encountered in APNC synthesis and characterization. For example, we show that several reducing agents employed in APNC synthesis, including the commonly used reagent NaBH4, do not always behave as anticipated. Indeed, we highlight one case where NaBH4 reduces the ligand and not the metal center, and other cases where NaBH4 acts as a Brønstead base instead of a reducing agent. In addition, we have identified several instances where the use of phase transfer agents, which were added to mediate APNC formation, played no role in the nanocluster synthesis, and likely made the isolation of pure material more difficult. We have also identified several cases of cluster misidentification driven by spurious or ambiguous characterization data, most commonly collected by mass spectrometry. To address these challenges, we propose that the nanocluster community adopt a standard protocol of characterization, similar to those used by the organometallic and coordination chemistry communities. This protocol requires that many complementary techniques be used in concert to confirm formulation, structure, and analytical purity of APNC samples. Two techniques that are underutilized in this regard are combustion analysis and NMR spectroscopy. NMR spectroscopy, in particular, can provide information on purity and formulation that are difficult to collect with any other technique. X-ray absorption spectroscopy is another powerful method of nanocluster characterization, especially in cases where single crystals for X-ray diffraction are not forthcoming. Chromatographic techniques can also be extremely valuable for assessing purity, but are rarely used during APNC characterization. Our goal with this Account is to begin a discussion with respect to the best protocols for nanocluster synthesis and characterization. We believe that embracing a standard characterization protocol would make APNC synthesis more reliable, thereby accelerating their integration into a variety of technologies.
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Affiliation(s)
- Andrew W. Cook
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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Hartmann NJ, Wu G, Hayton TW. Synthesis and reactivity of a nickel(ii) thioperoxide complex: demonstration of sulfide-mediated N 2O reduction. Chem Sci 2018; 9:6580-6588. [PMID: 30310590 PMCID: PMC6115681 DOI: 10.1039/c8sc02536c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 06/26/2018] [Indexed: 11/21/2022] Open
Abstract
The “masked” terminal nickel sulfide [K(18-crown-6)][LtBuNiII(S)] mediates the reduction of N2O by CO, via the thioperoxide complex [K(18-crown-6)][LtBuNiII(η2-SO)].
The thiohyponitrite ([SNNO]2–) complex, [K(18-crown-6)][LtBuNiII(κ2-SNNO)] (LtBu = {(2,6-iPr2C6H3)NC(tBu)}2CH), extrudes N2 under mild heating to yield [K(18-crown-6)][LtBuNiII(η2-SO)] (1), along with minor products [K(18-crown-6)][LtBuNiII(η2-OSSO)] (2) and [K(18-crown-6)][LtBuNiII(η2-S2)] (3). Subsequent reaction of 1 with carbon monoxide (CO) results in the formation of [K(18-crown-6)][LtBuNiII(η2-SCO)] (4), [K(18-crown-6)][LtBuNiII(S,O:κ2-SCO2)] (5), [K(18-crown-6)][LtBuNiII(κ2-CO3)] (6), carbonyl sulfide (COS) (7), and [K(18-crown-6)][LtBuNiII(S2CO)] (8). To rationalize the formation of these products we propose that 1 first reacts with CO to form [K(18-crown-6)][LtBuNiII(S)] (I) and CO2, via O-atom abstraction. Subsequently, complex I reacts with CO or CO2 to form 4 and 5, respectively. Similarly, the formation of complex 6 and COS can be rationalized by the reaction of 1 with CO2 to form a putative Ni(ii) monothiopercarbonate, [K(18-crown-6)][LtBuNiII(κ2-SOCO2)] (11). The Ni(ii) monothiopercarbonate subsequently transfers a S-atom to CO to form COS and [K(18-crown-6)][LtBuNiII(κ2-CO3)] (6). Finally, the formation of 8 can be rationalized by the reaction of COS with I. Critically, the observation of complexes 4 and 5 in the reaction mixture reveals the stepwise conversion of [K(18-crown-6)][LtBuNiII(κ2-SNNO)] to 1 and then I, which represents the formal reduction of N2O by CO.
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Affiliation(s)
- Nathaniel J Hartmann
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California , 93106 USA .
| | - Guang Wu
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California , 93106 USA .
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California , 93106 USA .
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Cook AW, Wu G, Hayton TW. A Re-examination of the Synthesis of Monolayer-Protected Co x(SCH 2CH 2Ph) m Nanoclusters: Unexpected Formation of a Thiolate-Protected Co(II) T3 Supertetrahedron. Inorg Chem 2018; 57:8189-8194. [PMID: 29943571 DOI: 10.1021/acs.inorgchem.8b00672] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we report a re-examination of the synthesis and characterization of monolayer-protected Co x(SCH2CH2Ph) m nanoclusters. These clusters were reportedly formed by the reaction of CoCl2 with NaBH4 in the presence of HSCH2CH2Ph and were suggested to contain between 25 and 30 Co atoms. In our hands, however, we found no experimental evidence to support the existence of these large clusters in the reaction mixture. Instead, this reaction results in the relatively clean formation of the cobalt(II) coordination complex [Co10(SCH2CH2Ph)16Cl4] (1). Complex 1 has been fully characterized using a wide variety of techniques, including single-crystal X-ray crystallography, NMR spectroscopy, mass spectrometry, and magnetometry. This complex represents the first example of a thiolate-protected Co(II) T3 supertetrahedral cluster.
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Affiliation(s)
- Andrew W Cook
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , United States
| | - Guang Wu
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106 , United States
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