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Khambhati DP, Sachinthani KAN, Rheingold AL, Nelson TL. Regioselective copper-catalyzed direct arylation of benzodithiophene-S,S-tetraoxide. Chem Commun (Camb) 2017; 53:5107-5109. [DOI: 10.1039/c7cc01781b] [Citation(s) in RCA: 14] [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: 12/13/2022]
Abstract
An efficient copper-catalyzed direct arylation reaction for the regioselective functionalization of benzodithiophene-S,S-tetraoxide has been developed.
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Affiliation(s)
- D. P. Khambhati
- Department of Chemistry
- Oklahoma State University
- Stillwater
- USA
| | | | | | - T. L. Nelson
- Department of Chemistry
- Oklahoma State University
- Stillwater
- USA
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Etheridge FS, Fernando R, Golen JA, Rheingold AL, Sauve G. Tuning the optoelectronic properties of core-substituted naphthalene diimides by the selective conversion of imides to monothioimides. RSC Adv 2015. [DOI: 10.1039/c5ra05920h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Molecules with a low optical gap and high electron affinity were obtained via selective thionation of the distal carbonyls of 2,6-dialkylamino core-substituted naphthalene diimide.
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Affiliation(s)
- F. S. Etheridge
- Department of Chemistry
- Case Western Reserve University
- Cleveland
- USA
| | - R. Fernando
- Department of Chemistry
- Case Western Reserve University
- Cleveland
- USA
| | - J. A. Golen
- Department of Chemistry and Biochemistry
- UMass Dartmouth
- Dartmouth
- USA
| | - A. L. Rheingold
- Department of Chemistry and Biochemistry
- University of California at San Diego
- La Jolla
- USA
| | - G. Sauve
- Department of Chemistry
- Case Western Reserve University
- Cleveland
- USA
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Brechin EK, Sañudo EC, Wernsdorfer W, Boskovic C, Yoo J, Hendrickson DN, Yamaguchi A, Ishimoto H, Concolino TE, Rheingold AL, Christou G. Single-Molecule Magnets: Structure and Properties of [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 with Spin S = 13. Inorg Chem 2005; 44:502-11. [PMID: 15679378 DOI: 10.1021/ic048857a] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [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
The reaction of 2-(hydroxyethyl)pyridine (hepH) with a 2:1 molar mixture of [Mn3O(O2CMe)6(py)3]ClO4 and [Mn3O(O2CMe)6(py)3] in MeCN afforded the new mixed-valent (16Mn(III), 2Mn(II)), octadecanuclear complex [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 (1) in 20% yield. Complex 1 crystallizes in the triclinic space group P. Direct current magnetic susceptibility studies in a 1.0 T field in the 5.0-300 K range, and variable-temperature variable-field dc magnetization studies in the 2.0-4.0 K and 2.0-5.0 T ranges were obtained on polycrystalline samples. Fitting of magnetization data established that complex 1 possesses a ground-state spin of S = 13 and D = -0.18 K. This was confirmed by the value of the in-phase ac magnetic susceptibility signal. Below 3 K, the complex exhibits a frequency-dependent drop in the in-phase signal, and a concomitant increase in the out-of-phase signal, consistent with slow magnetization relaxation on the ac time scale. This suggests the complex is a single-molecule magnet (SMM), and this was confirmed by hysteresis loops below 1 K in magnetization versus dc field sweeps on a single crystal. Alternating current and direct current magnetization data were combined to yield an Arrhenius plot from which was obtained the effective barrier (U(eff)) for magnetization reversal of 21.3 K. Below 0.2 K, the relaxation becomes temperature-independent, consistent with relaxation only by quantum tunneling of the magnetization (QTM) through the anisotropy barrier via the lowest-energy MS = +/-13 levels of the S = 13 spin manifold. Complex 1 is thus the SMM with the largest ground-state spin to display QTM.
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Affiliation(s)
- E K Brechin
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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Walters MA, Sireci A, Incarvito CD, Rheingold AL. Crystal structure of bis(acetonitrile)bis[μ-(benzylthiolato)] hexacarbonyl-di(molybdenum), [Mo(CO)3(SCH2C6H5)(CH3CN)]2. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.jg.271] [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: 11/24/2022]
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Walters MA, Sireci A, Incarvito CD, Rheingold AL. Crystal structure of bis(acetonitrile)bis[μ-(benzylthiolato)] hexacarbonyl-di(molybdenum), [Mo(CO)3(SCH2C6H5)(CH3CN)]2. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.1.271] [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: 11/24/2022]
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Hong FE, Fehlner TP, Rheingold AL. Coupling of a .eta.5-borole complex via a B-O-B link by reaction of the B-Br derivative with KOH. X-ray structure of {1-[.eta.5-(2,3,4,5-Ph4C4B)][.eta.5-(C5H5)]Co}2O. Organometallics 2002. [DOI: 10.1021/om00050a068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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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Oyumi Y, Brill TB, Rheingold AL, Haller TM. Crystal structure and molecular dynamics of the energetic nitramine 1,3,5,5-tetranitrohexahydropyrimidine and a comparison with 1,3,3,5,7,7-hexanitro-1,5-diazacyclooctane and 1,3,3-trinitroazetidine. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100266a033] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stroup AN, Rockwell AL, Rheingold AL, Gierasch LM. Crystal structure of cyclo(Gly1-L-Pro2-D-Phe3-L-Ala4-L-Pro5): a cyclic pentapeptide with a Gly-L-Pro .delta. turn. J Am Chem Soc 2002. [DOI: 10.1021/ja00223a041] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [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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Amini MM, Rheingold AL, Taylor RW, Zuckerman JJ. A new environment for water. The first authenticated example of water molecules engaged in twin, three-center hydrogen bonds. The crystal and molecular structure of the dimethyltin dichloride complex [(Me2SnCl2.H2O)2.18-crown-6]n. J Am Chem Soc 2002. [DOI: 10.1021/ja00335a095] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [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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Roat RM, Yolles S, Rheingold AL. Oxidative addition reactions of potassium tetrachloroplatinate(II) with N,N-dialkylacetamides under mild reaction conditions. Synthesis of [cis-Pt(CH2N(CH3)C(CH3)O)2-trans-Cl2] and [trans-Pt(OC(CH3)N(CH3)2)2-trans-Cl2]. Inorg Chem 2002. [DOI: 10.1021/ic00237a037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stoner CE, Rheingold AL, Brill TB. Thermal decomposition of energetic materials. 48. Structures and decomposition mechanisms of copper(II) complexes of furazans (1,2,5-oxadiazoles). Inorg Chem 2002. [DOI: 10.1021/ic00003a003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kegley SE, Bergstrom DT, Crocker LS, Weiss EP, Berndt WG, Rheingold AL. Preparation of d4 molybdenum-olefin complexes [Cp(diphos)Mo(CO)(ethylene)]+PF6- and [Cp(Pom-Pom)Mo(CO)(ethylene)]+PF6- (Pom-Pom = 1,2-bis(dimethoxyphosphino)ethane) and reactivity studies with carbanion nucleophiles. Organometallics 2002. [DOI: 10.1021/om00049a013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Oyumi Y, Rheingold AL, Brill TB. Thermal decomposition of energetic materials. 16. Solid-phase structural analysis and the thermolysis of 1,4-dinitrofurazano[3,4-b]piperazine. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100410a046] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Scott JP, Budge JR, Rheingold AL, Gates BC. Molecular chemistry of bimetallic clusters on the basic .gamma.-Al2O3 surface: synthesis, reactivity, and catalytic activity of [H3RuOs3(CO)12]-{Al} and related structures. J Am Chem Soc 2002. [DOI: 10.1021/ja00259a023] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Oyumi Y, Brill TB, Rheingold AL, Lowe-Ma C. Thermal decomposition of energetic materials. 2. The thermolysis of nitrate and perchlorate salts of the pentaerythrityltetrammonium ion, C(CH2NH3)44+, by rapid-scan FTIR spectroscopy. The crystal structure of pentaerythrityltetrammonium nitrate ([C(CH2NH3)4](NO3)4). ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100257a033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hampden-Smith MJ, Williams DS, Rheingold AL. Synthesis and characterization of alkali-metal titanium alkoxide compounds MTi(O-iso-Pr)5 (M = Li, Na, K): single crystal x-ray diffraction structure of [LiTi(O-iso-Pr)5]2. Inorg Chem 2002. [DOI: 10.1021/ic00345a033] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bandyopadhyay AK, Khattar R, Puga J, Fehlner TP, Rheingold AL. Boron in new environments. Structure and reaction properties of discrete, mixed-metal, hexanuclear borides. Inorg Chem 2002. [DOI: 10.1021/ic00029a024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Stroup AN, Rheingold AL, Rockwell AL, Gierasch LM. Crystal structure of cyclo(Gly-L-Pro-D-Phe-Gly-Val): an example of a new type of three-residue turn. J Am Chem Soc 2002. [DOI: 10.1021/ja00257a040] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Oyumi Y, Brill TB, Rheingold AL. Thermal decomposition of energetic materials. Part 9. Polymorphism, crystal structures, and thermal decomposition of polynitroazabicyclo[3.3.1]nonanes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100402a052] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bao QB, Landon SJ, Rheingold AL, Haller TM, Brill TB. Comparison of the self-reactivity of [CpCo(PP)I]+ complexes, PP = Ph2P(CH2)nPPh2 (n = 1-4), leading to bridged and oxidized dangling PP. Reactions, spectral studies, and structures of [CpCo(dppm)I]I.CHCl3, CpCo[dppm(O)]I2, and Cp2Co2I4(.mu.-dpppent). Inorg Chem 2002. [DOI: 10.1021/ic00200a021] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Whitmire KH, Lagrone CB, Rheingold AL. Lewis basicity of carbonyl oxygen in the presence of a heteroatom: reaction of decacarbonylbismuthtriferrate(1-) with trifluoromethyl methylsulfonate. Inorg Chem 2002. [DOI: 10.1021/ic00234a039] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Whitmire KH, Cassidy JM, Rheingold AL, Ryan RR. A series of thallium-iron carbonyl cluster molecules: structural comparisons of [Et4N]2[Tl2Fe4(CO)16], [Et4N]4[Tl4Fe8(CO)30], and [Et4N]6[Tl6Fe10(CO)36]. Inorg Chem 2002. [DOI: 10.1021/ic00281a007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Oyumi Y, Rheingold AL, Brill TB. Thermal decomposition of energetic materials. 19. Unusual condensed-phase and thermolysis properties of a mixed azidomethyl nitramine: 1,7-diazido-2,4,6-trinitro-2,4,6-triazaheptane. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100288a031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Oyumi Y, Brill TB, Rheingold AL. Thermal decomposition of energetic materials. 7. High-rate FTIR studies and the structure of 1,1,1,3,6,8,8,8-octanitro-3,6-diazaoctane. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100268a033] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [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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Bao QB, Geib SJ, Rheingold AL, Brill TB. Crystal structures and 1JPt-P correlations for trialkyl phosphite-platinum(II) complexes: [Pt[P(OMe)3]4](PF6)2, [Pt[P(OMe)3]3[P(O)(OMe)2]]PF6, cis-Pt[P(OMe)3]2[P(O)(OMe)2]2, [ClPt[P(OMe)3]3]PF6, and cis-Cl2Pt[P(OMe)3]2. Inorg Chem 2002. [DOI: 10.1021/ic00268a009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rheingold AL, Ng SW, Zuckerman JJ. X-ray crystal and molecular structures of the monomeric 1:1 adducts of diphenyltin(IV) dichloride and trimethyltin(IV) chloride with 2,6-dimethylpyridine (2,6-lutidine) N-oxide. Organometallics 2002. [DOI: 10.1021/om00080a012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Palopoli SF, Geib SJ, Rheingold AL, Brill TB. Synthesis and modes of coordination of energetic nitramine ligands in copper(II), nickel(II), and palladium(II) complexes. Inorg Chem 2002. [DOI: 10.1021/ic00290a015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Walters MA, Sireci A, Incarvito CD, Rheingold AL. Crystal structure of bis(acetonitrile)bis[μ-(benzylthiolato)]hexacarbonyldi( molybdenum), [Mo(CO)3(SCH2C6H5)(CH3CN)]2. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.2.271] [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: 11/24/2022]
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Kuroda-Sowa T, Lam M, Rheingold AL, Frommen C, Reiff WM, Nakano M, Yoo J, Maniero AL, Brunel LC, Christou G, Hendrickson DN. Effects of paramagnetic ferrocenium cations on the magnetic properties of the anionic single-molecule magnet [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]-. Inorg Chem 2001; 40:6469-80. [PMID: 11720503 DOI: 10.1021/ic010547u] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [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
The preparation and physical characterization are reported for the single-molecule magnet salts [M(Cp')(2)](n)()[Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (M = Fe, n = 1, Cp' = C(5)Me(5) (2a), C(5)H(5) (2b); M = Co, n = 1, Cp' = C(5)Me(5) (2c), C(5)H(5) (2d); M = Fe, n = 2, Cp' = C(5)Me(5) (2e), C(5)H(5) (2f)) to investigate the effects of paramagnetic cations on the magnetization relaxation behavior of [Mn(12)]- anionic single-molecule magnets. Complex 2a.2H(2)O crystallizes in the orthorhombic space group Aba2, with cell dimensions at 173 K of a = 25.6292(2) A, b = 25.4201(3) A, c = 29.1915(2) A, and Z = 4. Complex 2c.2CH(2)Cl(2).C(6)H(14) crystallizes in the monoclinic space group P2(1)/c, with cell dimensions at 173 K of a = 17.8332(6) A, b = 26.2661(9) A, c = 36.0781(11) A, beta = 92.8907(3) degrees, and Z = 4. These two salts consist of either paramagnetic [Fe(C(5)Me(5))(2)]+ cations or diamagnetic [Co(C(5)Me(5))(2)]+ cations, and [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]- anions. The structures of the anions in the two salts are similar, consisting of a central Mn(4)O(4) cubane moiety, surrounded by a nonplanar ring of eight Mn atoms that are bridged by and connected to the cube via mu(3)-O(2)- ions. The oxidation states of four Mn sites out of eight outer Mn ions in complex 2a were assigned to be +2.75 from the valence bond sum analysis although the disordering of bridging carboxylates prevents more precise determination. On the other hand in complex 2c, one Mn site out of eight outer Mn ions was identified as a Mn(II) ion, accommodating the "extra" electron; this was deduced by a valence bond sum analysis. Thus, the anion in complex 2c has a Mn(II)(1)Mn(III)(7)Mn(IV)(4) oxidation state description. The Jahn-Teller axes of the Mn(III) ions in both anions are roughly aligned in one direction. All complexes studied exhibit a single out-of-phase ac magnetic susceptibility (chi"(M)) signal in the 4.6-4.8 K range for complexes 2a-2d and in the 2.8-2.9 K range for complexes 2e and 2f at 1 kHz ac frequency. The temperature of the chi"(M) peaks is frequency dependent, as expected for single-molecule magnets. From Arrhenius plots of the frequency dependence of the temperature of the chi"(M) maxima, the effective energy barriers U(eff) for changing spin from "up" to spin "down" were estimated to be 50-54 K for complexes 2a-2d and 27-28 K for complexes 2e and 2f. The least-squares fits of the reduced magnetization data indicate that both complexes 2a and 2d have ground states of S = (21)/(2). High-frequency EPR spectra were recorded for complex 2a at frequencies of 217, 327, and 434 GHz in the 4.5-30 K range. The observed transition fields were least-squares fit to give g = 1.91, D = -0.35 cm(-1), and B(4)(0) = -3.6 x 10(-7) cm(-1) for the S = (21)/(2) ground state. The effective energy barrier U(eff) is slightly lower than U estimated from D, which is consistent with the thermally assisted tunneling model. Magnetization hysteresis loops were observed for complexes 2a and 2c. Although 2a was oriented in a different manner as expected by strong magnetic field, both complexes show clear hysteresis loops with some steps on them, indicating that the effect of the magnetic cation on the magnetization relaxation of the anionic [Mn(12)]- complex is rather small. An 11% (57)Fe enriched complex 2b was studied by means of Mössbauer spectroscopy down to as low as 1.7 K. Slow paramagnetic relaxation broadening and magnetic hyperfine splitting were evident in the low-temperature spectra, indicating that the iron atoms feel a growing magnetic field owing to slow magnetization reversal in the [Mn(12)]- anions.
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Affiliation(s)
- T Kuroda-Sowa
- Department of Chemistry and Biochemistry-0358, University of California at San Diego, La Jolla, CA 92093-0358, USA
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Rheingold AL, Liable-Sands LM, Trofimenko S. Hydrotris[3-(1-naphthylpyrazol-1-yl)]borate and hydrotris[3-(2-naphthylpyrazol-1-yl)]borate: two novel homoscorpionate ligands of varying coordination behavior. Inorg Chem 2001; 40:6509-13. [PMID: 11720511 DOI: 10.1021/ic010751h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [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)
- A L Rheingold
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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Chang SC, Sommer RD, Rheingold AL, Goldberg DP. A model complex of a possible intermediate in the mechanism of action of peptide deformylase: first example of an (N2S)zinc(II)-formate complex. Chem Commun (Camb) 2001:2396-7. [PMID: 12240093 DOI: 10.1039/b106865m] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and crystallographic characterization of a new (N2S)zinc-alkyl complex and (N2S)zinc-formate complex is described; the bonding mode of the formate complex has implications for the mechanism of action of the enzyme peptide deformylase.
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Affiliation(s)
- S C Chang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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Abstract
Reaction of Tpt-Bu,MeCo-H with O2 proceeds via a spectroscopically observable hydroperoxide whose reactivity in solution and in the solid state differ dramatically.
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Affiliation(s)
- S Thyagarajan
- Department of Chemistry and Biochemistry, Center for Catalytic Science and Technology, University of Delaware, Newark, DE 19716, USA
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Ghiladi RA, Kretzer RM, Guzei I, Rheingold AL, Neuhold YM, Hatwell KR, Zuberbühler AD, Karlin KD. (F(8)TPP)Fe(II)/O(2) reactivity studies [F(8)TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]: spectroscopic (UV-Visible and NMR) and kinetic study of solvent-dependent (Fe/O(2) = 1:1 or 2:1) reversible O(2)-reduction and ferryl formation. Inorg Chem 2001; 40:5754-67. [PMID: 11681882 DOI: 10.1021/ic0105866] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this report, we describe in detail the O(2)-binding chemistry of the metalloporphyrin (F(8)TPP)Fe(II) (1). This complex was synthesized from aqueous dithionite reduction of (F(8)TPP)Fe(III)-Cl (X-ray structure reported: C(55)H(36)ClF(8)FeN(4)O; a = 13.6517(2) A, b = 13.6475(2) A, c = 26.3896(4), alpha = 90 degrees, beta = 89.9776(4) degrees, gamma = 90 degrees; monoclinic, P2(1)/c, Z = 4). Complex 1 crystallizes from toluene/heptane solvent system as a bis(toluene) solvate, (F(8)TPP)Fe(II).(C(7)H(8))(2), with ferrous ion in the porphyrin plane (C(58)H(36)F(8)FeN(4); a = 20.9177(2) A, b = 11.7738(2) A, c = 19.3875(2), alpha = 90 degrees, beta = 108.6999(6) degrees, gamma = 90 degrees; monoclinic, C2/c, Z = 4; Fe-N(4)(av) = 2.002 A; N-Fe-N (all) = 90.0 degrees ). Close metal-arene contacts are also observed at 3.11-3.15 A. Upon oxygenation of 1 at 193 K in coordinating solvents, UV-visible and (2)H and (19)F NMR spectroscopies revealed the presence of a reversibly formed dioxygen adduct, formulated as the heme-superoxo complex (S)(F(8)TPP)Fe(III)-(O(2)(-)) (2) (S = solvent) [(i) tetrahydrofuran (THF) solvent: UV-visible, 416 (Soret), 536 nm; (2)H NMR: delta(pyrrole) 8.9 ppm; (ii) EtCN solvent: UV-visible, 414 (Soret), 536 nm; (iii) acetone solvent: UV-visible, 416 (Soret), 537 nm; (2)H NMR: delta(pyrrole) 8.9 ppm]. Dioxygen-uptake manometry (THF, 193 K) revealed an O(2):1 oxygenation stoichiometry of 1.02:1, consistent with the heme-superoxo formulation of 2. Stopped-flow UV-visible spectrophotometry studies of the (F(8)TPP)Fe(II) (1)/O(2) reaction in EtCN and THF solvents were able to provide kinetic and thermodynamic insight into the reversible formation of 2 [(i) EtCN: Delta H degrees = -40 +/- 5 kJ/mol; Delta S degrees = -105 +/- 23 J/(K mol); k(1) = (5.57 +/- 0.04) x 10(3) M(-)(1) s(-)(1) (183 K); Delta H(++) = 38.6 +/- 0.2 kJ/mol; Delta S(++) = 42 +/- 1 J/(K mol); (ii) THF: Delta H* = -37.5 +/- 0.4 kJ/mol; Delta S* = -109 +/- 2 J/(K mol)]. The (F(8)TPP)Fe(II) (1)/O(2) reaction was also examined at reduced temperatures in noncoordinating solvents (toluene, CH(2)Cl(2)), where UV-visible and (2)H and (19)F NMR spectroscopies also revealed the presence of a reversibly formed adduct, formulated as the peroxo-bridged dinuclear complex [(F(8)TPP)Fe(III)](2)-(O(2)(2)(-)) (3) [CH(2)Cl(2): UV-visible, 414 (Soret), 535 nm; (2)H NMR, delta(pyrrole) 17.5 ppm]. Dioxygen-uptake spectrophotometric titrations revealed a stoichiometry of 2 (F(8)TPP)Fe(II) (1) per O(2) upon full formation of 3. Addition of a nitrogenous base, 4-(dimethylamino)pyridine, to a cold solution of 3 in dichloromethane gave rapid formation of the iron(IV)-oxo ferryl species (DMAP)(F(8)TPP)Fe(IV)==O (4), based upon UV-visible [417 (Soret), 541 nm] and (2)H NMR (delta(pyrrole) = 3.5 ppm) spectroscopic characterization. These detailed investigations into the O(2)-adducts and "ferryl" species formed from (F(8)TPP)Fe(II) (1) may be potentially important for a full understanding of our ongoing heme-copper oxidase model studies, which employ 1 or similar "tethered" (i.e., covalently attached Cu-chelate) porphyrin analogues in heme/Cu heterobinuclear systems.
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Affiliation(s)
- R A Ghiladi
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, USA
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38
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Kingsley S, Chandrasekhar V, Incarvito CD, Lam MK, Rheingold AL. Tethered pyrazolyl phosphinate: pyrazolyl-N- and phosphoryl-O-metal coordination in Ph(2)P(O)[OCH(2)CH(2)(3,5-Me(2)Pz)]. Inorg Chem 2001; 40:5890-6. [PMID: 11681901 DOI: 10.1021/ic010454c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [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
Phosphorus pyrazolides, P(O)(3,5-Me(2)Pz)(3) or RP(E)(3,5-Me(2)Pz)(2) [E = S or O, R = Me or Ph], are hydrolytically sensitive particularly upon interaction with transition metal ions. In this paper, we report a new tethered pyrazolyl phosphinate, Ph(2)P(O)[OCH(2)CH(2)(3,5-Me(2)Pz)] DPEP (1), where the pyrazolyl group is separated from the phosphorus by means of an ethyleneoxy spacer. 1 has two potential coordination sites in the form of a phosphoryl oxygen atom and a pyrazolyl nitrogen atom. 1 forms hydrolytically stable complexes, (DPEP-CoCl(2))(n)(2), (DPEP)(2)-CuCl(2) (3), (DPEP-ZnCl(2))(n )(4), and (DPEP)(2)-PdCl(2) (5). The cobalt(II) and the zinc(II) complexes 2 and 4 show a zigzag polymeric structure in the solid state with a tetrahedral coordination geometry around the metal ion; the ligand DPEP coordinates through its phosphoryl oxygen and the pyrazolyl nitrogen to two neighboring metal ions and functions as a bridging ligand to form the polymeric structure. In contrast to 2 and 4, the copper(II) and the palladium(II) complexes 3 and 5 show a square-planar geometry around the metal ion. Exclusive coordination through the pyrazolyl nitrogens of the ligand 1 is observed. An extensive supramolecular sheetlike two-dimensional polymeric network is observed in the solid-state structures of 3 and 5 as a result of two weak interactions: (a) an intermolecular C-H- - -O interaction involving the phosphoryl oxygen and an aromatic C-H and (b) a pi-pi face-to-face stacking interaction between the phenyl groups of two adjacent molecules.
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Affiliation(s)
- S Kingsley
- Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
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39
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Southern JS, Green MT, Hillhouse GL, Guzei IA, Rheingold AL. Chemistry of coordinated nitroxyl. Reagent-specific protonations of trans-Re(CO)(2)(NO)(PR(3))(2) (R = Ph, Cy) that give the neutral nitroxyl complexes cis,trans-ReCl(CO)(2)(NH=O)(PR(3))(2) or the cationic hydride complex [trans,trans-ReH(CO)(2)(NO)(PPh(3))(2)(+)][SO(3)CF(3)(-)]. Inorg Chem 2001; 40:6039-46. [PMID: 11681923 DOI: 10.1021/ic010669m] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [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
The reactions of hydrochloric and triflic acids with the five-coordinate nitrosyl complexes trans-Re(CO)(2)(NO)(PR(3))(2) (2a, R = Ph; 2b, R = Cy) have been investigated. Reaction of anhydrous HCl with 2 results in a formal protonation of the nitrosyl ligand and addition of chloride to the metal, giving the neutral nitroxyl complex cis,trans-ReCl(CO)(2)(NH=O)(PR(3))(2) (3a, R = Ph; 3b, R = Cy). Reaction of Brønsted bases with 3a or 3b results in clean conversion of 3 to 2 when the base is appropriately strong (pK(b) approximately 7). Addition of HOSO(2)CF(3) to solutions of 2a results in protonation at the metal and formation of the cationic rhenium hydride [trans,trans-ReH(CO)(2)(NO)(PPh(3))(2)(+)][SO(3)CF(3)(-)] (4) in 74% yield; the deuteride [trans,trans-Re((2)H)(CO)(2)(NO)(PPh(3))(2)(+)][SO(3)CF(3)(-)] (4-d) was analogously prepared from (2)HOSO(2)CF(3). 4 crystallized from CH(2)Cl(2)/Et(2)O solution in the orthorhombic space group Pnma, with a = 17.2201(2) A, b = 23.6119(3) A, c = 9.2380(2) A, and Z = 4. The least-squares refinement converged to R(F) = 0.039 and R(wF(2)()) = 0.063 for the 4330 unique data with I > 2 sigma(I). The structure of 4 shows that the hydride (Re-H = 1.74 A) occupies the position trans to the linear nitrosyl ligand (Re-N-O = 178.1(4) degrees ) in the pseudooctahedral complex cation. Complex 4 does not react with chloride to give 3a. DFT calculations carried out on free nitroxyl and its model complexes [Re(CO)(5)(NH=O)(+)] (5), [mer,trans-Re(CO)(3)(NH=O)(PH(3))(2)(+)] (6), and cis,trans-ReCl(CO)(2)(NH=O)(PH(3))(2) (7) indicate that coordinated nitroxyl acts as both a sigma-donor and pi-acceptor ligand, consistent with the observed trend for nu(NO) in free HN=O (1563 cm(-1)), [mer,trans-Re(CO)(3)(NH=O)(PPh(3))(2)(+)] (1, 1391 cm(-1)), 3a (1376 cm(-1)), and 3b (1335 cm(-1)).
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Affiliation(s)
- J S Southern
- Searle Chemistry laboratory, Department of Chemistry, The University of Chicago, Illinois 60637, USA
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40
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Schuetz SA, Day VW, Sommer RD, Rheingold AL, Belot JA. Anhydrous lanthanide Schiff base complexes and their preparation using lanthanide triflate derived amides. Inorg Chem 2001; 40:5292-5. [PMID: 11559096 DOI: 10.1021/ic010060l] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [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)
- S A Schuetz
- Department of Chemistry and Center for Materials Research, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, USA
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41
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Pan L, Woodlock EB, Wang X, Lam KC, Rheingold AL. Novel silver(I)-organic coordination polymers: conversion of extended structures in the solid state as driven by argentophilic interactions. Chem Commun (Camb) 2001:1762-3. [PMID: 12240303 DOI: 10.1039/b104074j] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structurally distinct coordination polymers [Ag(bpp)]ClO4 1 and [Ag(bpp)]PF6 2 [bpp = 1,3-bis(4-pyridyl)propane] have been assembled; the conversion of 1 into 2 on treatment with NaPF6 is driven by argentophilic interactions and is the first such transformation reported for silver(I)-organic coordination polymers.
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Affiliation(s)
- L Pan
- Department of Chemistry, Campus Box 194, University of Colorado at Denver, P.O. Box 173364, Denver, Colorado 80217-3364, USA
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42
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Kolesnichenko V, Mason MH, Botts JB, Botts AM, Baroni TE, Heppert JA, Rheingold AL, Liable-Sands L, Yap GP. Tungsten oxo salicylate complexes from tungsten hexachloride reactions systems. Inorg Chem 2001; 40:5010-6. [PMID: 11531451 DOI: 10.1021/ic001456k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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
Tungsten hexachloride is a potent halogen-transfer agent, capable of reacting directly with salicylic acid to generate a tungsten oxo fragment and salicoyl chloride. As a result, oxo complexes dominate the chemistry of tungsten(VI) salicylates. Both mono- and disalicylate substituted tungsten oxo complexes are accessible. The Brønsted free acid W(=O)Cl(Hsal)(sal) complex is a sparingly soluble, presumably polymeric material that can be dissolved in THF. The THF adduct has been characterized by NMR spectroscopy, although an X-ray crystallographic study indicates that the product cocrystallizes with a structurally analogous d(1) WCl(2)(Hsal.THF)(sal) byproduct. The remaining chloride ligand in W(=O)Cl(Hsal)(sal) is replaced by a bridging oxo unit when the reaction contains a significant excess of salicylic acid. The product "linear" oxo bridged ditungsten complex, [W(=O)(Hsal)(sal)](2)O, forms intramolecular hydrogen bonds, accounting for its high solubility in noncoordinating solvents. An X-ray study shows that the intramolecular Hsal.sal hydrogen bonding in this complex accommodates a more linear W-O-W arrangement than does a previously observed class of isostructural diolate derivatives. Tungsten oxo tetrachloride, formed in the initial reaction between salicylic acid and WCl(6), also reacts with the salicoyl chloride byproduct to generate tungsten salicoylate (OAr-2-COCl) complexes.
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Affiliation(s)
- V Kolesnichenko
- Department of Chemistry and Biochemistry, University of Delaware, Newark 19716, USA
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43
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Liu X, Wu Z, Cai H, Yang Y, Chen T, Vallet CE, Zuhr RA, Beach DB, Peng ZH, Wu YD, Concolino TE, Rheingold AL, Xue Z. Reactions of tetrakis(dimethylamide)-titanium, -zirconium and -hafnium with silanes: synthesis of unusual amide hydride complexes and mechanistic studies of titanium-silicon-nitride (Ti-Si-N) formation. J Am Chem Soc 2001; 123:8011-21. [PMID: 11506557 DOI: 10.1021/ja010744s] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [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
M(NMe(2))(4) (M = Ti, Zr, Hf) were found to react with H(2)SiR'Ph (R' = H, Me, Ph) to yield H(2), aminosilanes, and black solids. Unusual amide hydride complexes [(Me(2)N)(3)M(mu-H)(mu-NMe(2))(2)](2)M (M = Zr, 1; Hf, 2) were observed to be intermediates and characterized by single-crystal X-ray diffraction. [(Me(2)N)(3)M(mu-D)(mu-NMe(2))(2)](2)M (1-d(2), 2-d(2)) were prepared through reactions of M(NMe(2))(4) with D(2)SiPh(2). Reactions of (Me(2)N)(3)ZrSi(SiMe(3))(3) (5) with H(2)SiR'Ph were found to give aminosilanes and (Me(2)N)(2)Zr(H)Si(SiMe(3))(3) (6). These reactions are reversible through unusual equilibria such as (Me(2)N)(3)ZrSi(SiMe(3))(3) (5) + H(2)SiPh(2) right arrow over left arrow (Me(2)N)(2)Zr(H)Si(SiMe(3))(3) (6) + HSi(NMe(2))Ph(2). The deuteride ligand in (Me(2)N)(2)Zr(D)Si(SiMe(3))(3) (6-d(1)) undergoes H-D exchange with H(2)SiR'Ph (R' = Me, H) to give 6 and HDSiR'Ph. The reaction of Ti(NMe(2))(4) with SiH(4) in chemical vapor deposition at 450 degrees C yielded thin Ti-Si-N ternary films containing TiN and Si(3)N(4). Ti(NMe(2))(4) reacts with SiH(4) at 23 degrees C to give H(2), HSi(NMe(2))(3), and a black solid. HNMe(2) was not detected in this reaction. The reaction mixture, upon heating, gave TiN and Si(3)N(4) powders. Analyses and reactivities of the black solid revealed that it contained -H and unreacted -NMe(2) ligands but no silicon-containing ligand. Ab initio quantum chemical calculations of the reactions of Ti(NR(2))(4) (R = Me, H) with SiH(4) indicated that the formation of aminosilanes and HTi(NR(2))(3) was favored. These calculations also showed that HTi(NH(2))(3) (3b) reacted with SiH(4) or H(3)Si-NH(2) in the following step to give H(2)Ti(NH(2))(2) (4b) and aminosilanes. The results in the current studies indicated that the role of SiH(4) in its reaction with Ti(NMe(2))(4) was mainly to remove amide ligands as HSi(NMe(2))(3). The removal of amide ligands is incomplete, and the reaction thus yielded "=Ti(H)(NMe(2))" as the black solid. Subsequent heating of the black solid and HSi(NMe(2))(3) may then yield TiN and Si(3)N(4), respectively, as the Ti-Si-N materials.
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Affiliation(s)
- X Liu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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44
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Incarvito C, Rheingold AL, Gavrilova AL, Qin CJ, Bosnich B. Bimetallic reactivity. One-site addition two-metal oxidation reactions using a di-Co(II) complex of a binucleating ligand with 5- and 6-coordinate sites. Inorg Chem 2001; 40:4101-8. [PMID: 11487311 DOI: 10.1021/ic010235r] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preparation of an unsymmetrical binucleating ligand bearing a bridging oxadiazole ring flanked on one side by three ligands and on the other by four ligands is described. When bound to two metals, the ligand forms complexes where the metals are in 5- and 6-coordinate sites after the incorporation of an exogenous bridging ligand. A di-Co(2+) complex of this ligand has been prepared containing a hydroxide bridge. The complex is readily oxidized to the di-Co(3+) state by outer sphere electron transfer with ferrocenium ions. Addition of Br(2) or NO(2)(+) to the di-Co(2+) complex leads to the rapid formation of the di-Co(3+) bromo or nitro complexes, respectively. The ligand characteristics which allow for double oxidation with ferrocenium ions and for the one-site addition two-metal oxidations with Br(2) and NO(2)(+) are discussed in terms of mechanical coupling between the two metal sites.
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Affiliation(s)
- C Incarvito
- Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA
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45
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Abstract
Copper(I) complexes of the tridentate thioether ligands [PhB(CH(2)SCH(3))(3)] (abbreviated PhTt), [PhB(CH(2)SPh)(3)] (PhTt(Ph)), [PhB(CH(2)S(t)()Bu)(3)] (PhTt(t)()(Bu)), and [PhB(CH(2)S(p)()Tol)(3)] (PhTt(p)()(Tol)) and bidentate thioether ligands [Ph(2)B(CH(2)SCH(3))(2)] (Ph(2)Bt), [Et(2)B(CH(2)SCH(3))(2)] (Et(2)Bt), and [Ph(2)B(CH(2)SPh)(2)] (Ph(2)Bt(Ph)) have been prepared and characterized. The solution and solid state structures are highly sensitive to the identity of the borato ligand employed. Ligands possessing the smaller (methylthio)methyl donors, [PhTt] and [Ph(2)Bt], yielded tetrameric species, [(PhTt)Cu](4) and [(Ph(2)Bt)Cu](4), containing both terminal and bridging thioether ligation. The ligands containing the larger (arylthio)methyl groups, [PhTt(Ph)] and [PhTt(p)()(Tol)], form monomeric [PhTt(Ar)]Cu(NCCH(3)) in solution and one-dimensional extended structures in the solid state. Each complex type reacted cleanly with acetonitrile, pyridine, or triphenylphosphine generating the corresponding four-coordinate monomer, of which [PhTt(Ph)]Cu(PPh(3)), [PhTt(p)()(Tol)]Cu(PPh(3)), and [Et(2)Bt]Cu(PPh(3))(2) have been structurally characterized.
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Affiliation(s)
- C Ohrenberg
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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46
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Hughes RP, Williamson A, Sommer RD, Rheingold AL. The first transition metal complex of tetrafluorobenzyne: Ir(eta(5)-C(5)Me(5))(PMe(3))(eta(2)-C(6)F(4)). J Am Chem Soc 2001; 123:7443-4. [PMID: 11472184 DOI: 10.1021/ja010992o] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [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)
- R P Hughes
- Departments of Chemistry, 6128 Burke Laboratory Dartmouth College, Hanover, New Hampshire 03755, USA
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47
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Crich D, Li H, Yao Q, Wink DJ, Sommer RD, Rheingold AL. Direct synthesis of beta-mannans. A hexameric [-->3)-beta-D-Man-(1](3) subunit of the antigenic polysaccharides from Leptospira biflexa and the octameric (1-->2)-linked beta-D-mannan of the Candida albicans phospholipomannan. X-ray crystal structure of a protected tetramer. J Am Chem Soc 2001; 123:5826-8. [PMID: 11403627 DOI: 10.1021/ja015985e] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D Crich
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
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48
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Fogel L, Hsung RP, Wulff WD, Sommer RD, Rheingold AL. Simultaneous and stereoselective construction of planar and axial centers of chirality. J Am Chem Soc 2001; 123:5580-1. [PMID: 11389643 DOI: 10.1021/ja010091f] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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49
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Ewen JA, Elder MJ, Jones RL, Rheingold AL, Liable-Sands LM, Sommer RD. Chiral Ansa metallocenes with Cp ring-fused to thiophenes and pyrroles: syntheses, crystal structures, and isotactic polypropylene catalysts. J Am Chem Soc 2001; 123:4763-73. [PMID: 11457286 DOI: 10.1021/ja004266h] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [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
Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) and pyrroles (Pyr) are reported. The C2- and C1-symmetric heterocenes are dimethylsilyl bridged, have methyl groups adjacent to the bridgehead carbon atoms, and have aryl substituents protruding in the front. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2/MAO (MAO = methyl alumoxanes) is the most active metallocene catalyst for polypropylene reported to date. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 and rac-Me2Si(2,5-Me2-1-Ph-4-Cp[b]Pyr)2ZrCl2 have the same structure, and the former is 6 times more active, produces half the total enantiofacial errors, and is 3.5 times less regiospecific in propylene polymerizations at the same conditions. rac-Me2Si(2-Me-4-Ph-1-Ind)2ZrCl2/MAO is 3.5 times lower in activity than rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 catalyst, and while the former is the more stereospecific and the less regiospecific, the sum of these two enantioface errors is the same for both species. Fine-tuning the heterocene sterics by changing selected hydrogen atoms on the ligands to methyl groups influenced their catalyst activities, stereospecificites, regiospecificites, and isotactic polypropylene (IPP) Mw. Thus, both substituting a hydrogen atom adjacent to the phenyl ring with a methyl group on an azapentalenyl ligand system and replacing one and then two hydrogens on the phenyl ring with methyls on thiopentalenyl ligands provided increased polymer Tm and Mw with increasing ligand bulk. Polymer molecular weights are sensitive to and inversely proportional to MAO concentration, and the catalyst activities increase when hydrogen is added for molecular weight control. The polymer Tm values with the thiopentalenyls as TIBAL/[Ph3C][B(C6F5)4] systems were higher than with MAO as catalyst activator. A racemic C1, pseudo-meso complex with a hybrid dimethylsilyl-bridged 2-Me-4-Ph-1-Ind/2,5-Me2-4-Ph-1-Cp[b]Pyr ligand produced the first sample of IPP with all the steric pentad intensities fitting the enantiomorphic site control model. Speculative mechanistic considerations are offered regarding electronic effects of the heteroatoms and steric effects of the ligand structures, the preferred phenyl torsion angles, and anion effects.
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Affiliation(s)
- J A Ewen
- Catalyst Research Corporation, 14311 Golf View Trail, Houston, Texas 77059, USA
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50
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Sommer RD, Rheingold AL, Goshe AJ, Bosnich B. Supramolecular chemistry: molecular recognition and self-assembly using rigid spacer-chelators bearing cofacial terpyridyl palladium(II) complexes separated by 7 A. J Am Chem Soc 2001; 123:3940-52. [PMID: 11457144 DOI: 10.1021/ja004279v] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [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
Partially and fully aromatic molecular spacers bearing two symmetrically bound terpyridyl chelators have been prepared. These spacer-chelators were constructed to dispose the two terpyridyl ligands and their complexes with square planar metals cofacially with a separation of about 7 A between the two metals. Dipalladium(II) complexes of these spacer-chelators were prepared and characterized. These palladium complexes readily form large molecular rectangles with a linear linker such as 4,4'-dipyridyl. The dichlorodipalladium complex of the partially reduced spacer-chelator is capable of incarcerating planar aromatic and coordination compounds as guests. A crystal structure showing the incorporation of 9-methylanthracene has been determined. A 9-methylanthracene lies completely within the approximately 7 A space provided by the cleft formed by the two cofacially disposed chloro-palladium-terpyridyl units. The crystal structure shows additional pi-stacking interactions between a second 9-methylanthracene and neighboring receptors.
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Affiliation(s)
- R D Sommer
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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