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A Mixed-Valence Ti(II)/Ti(III) Inverted Sandwich Compound as a Regioselective Catalyst for the Uncommon 1,3,5-Alkyne Cyclotrimerization. Inorg Chem 2024; 63:8642-8653. [PMID: 38690944 PMCID: PMC11094787 DOI: 10.1021/acs.inorgchem.4c00149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
The synthesis, structure, and catalytic activity of a Ti(II)/Ti(III) inverted sandwich compound are presented in this study. Synthesis of the arene-bridged dititanium compound begins with the preparation of the titanium(IV) precursor [TiCl2(MesPDA)(thf)2] (MesPDA = N,N'-bis(2,4,6-trimethylphenyl)-o-phenylenediamide) (2). The reduction of 2 with sodium metal results in species [{Ti(MesPDA)(thf)}2(μ-Cl)3{Na}] (3) in oxidation state III. To achieve the lower oxidation state II, 2 undergoes reduction through alkylation with lithium cyclopentyl. This alkylation approach triggers a cascade of reactions, including β-hydride abstraction/elimination, hydrogen evolution, and chemical reduction, to generate the Ti(II)/Ti(III) compound [Li(thf)4][(TiMesPDA)2(μ-η6: η6-C6H6)] (4). X-ray and EPR characterization confirms the mixed-valence states of the titanium species. Compound 4 catalyzes a mild, efficient, and regiospecific cyclotrimerization of alkynes to form 1,3,5-substituted arenes. Kinetic data support a mechanism involving a binuclear titanium arene compound, similar to compound 4, as the resting state. The active catalyst promotes the oxidative coupling of two alkynes in the rate-limiting step, followed by a rapid [4 + 2] cycloaddition to form the arene product. Computational analysis of the resting state for the cycloaddition of trimethylsilylacetylene indicates a thermodynamic preference for stabilizing the 1,3,5-arene within the space between the two [TiMesPDA] fragments, consistent with the observed regioselectivity.
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Ti(III) Catalysts for CO 2/Epoxide Copolymerization at Unusual Ambient Pressure Conditions. Inorg Chem 2023; 62:14873-14887. [PMID: 37651747 PMCID: PMC10521022 DOI: 10.1021/acs.inorgchem.3c01249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Indexed: 09/02/2023]
Abstract
Titanium compounds in low oxidation states are highly reducing species and hence powerful tools for the functionalization of small molecules. However, their potential has not yet been fully realized because harnessing these highly reactive complexes for productive reactivity is generally challenging. Advancing this field, herein we provide a detailed route for the formation of titanium(III) orthophenylendiamido (PDA) species using [LiBHEt3] as a reducing agent. Initially, the corresponding lithium PDA compounds [Li2(ArPDA)(thf)3] (Ar = 2,4,6-trimethylphenyl (MesPDA), 2,6-diisopropylphenyl (iPrPDA)) are combined with [TiCl4(thf)2] to form the heterobimetallic complexes [{TiCl(ArPDA)}(μ-ArPDA){Li(thf)n}] (n = 1, Ar = iPr 3 and n = 2, Ar = Mes 4). Compound 4 evolves to species [Ti(MesPDA)2] (6) via thermal treatment. In contrast, the transformation of 3 into [Ti(iPrPDA)2] (5) only occurs in the presence of [LiNMe2], through a lithium-assisted process, as revealed by density functional theory (DFT). Finally, the Ti(IV) compounds 3-6 react with [LiBHEt3] to give rise to the Ti(III) species [Li(thf)4][Ti(ArPDA)2] (Ar = iPr 8, Mes 9). These low-valent compounds in combination with [PPN]Cl (PPN = bis(triphenylphosphine)iminium) are proved to be highly selective catalysts for the copolymerization of CO2 and cyclohexene epoxide. Reactions occur at 1 bar pressure with activity/selectivity levels similar to Salen-Cr(III) compounds.
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Synthesis, Characterization, and Reactivity of Low-Coordinate Titanium(III) Amido Complexes. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Investigation of the C-N Bond-Forming Step in a Photoinduced, Copper-Catalyzed Enantioconvergent N-Alkylation: Characterization and Application of a Stabilized Organic Radical as a Mechanistic Probe. J Am Chem Soc 2022; 144:4114-4123. [PMID: 35167268 PMCID: PMC9269863 DOI: 10.1021/jacs.1c13151] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Whereas photoinduced, copper-catalyzed couplings of nitrogen nucleophiles with alkyl electrophiles have recently been shown to provide an attractive approach to achieving a variety of enantioselective C-N bond constructions, mechanistic studies of these transformations have lagged the advances in reaction development. Herein we provide mechanistic insight into a previously reported photoinduced, copper-catalyzed enantioconvergent C-N coupling of a carbazole nucleophile with a racemic tertiary α-haloamide electrophile. Building on the isolation of a copper(II) model complex whose EPR parameters serve as a guide, we independently synthesize two key intermediates in the proposed catalytic cycle, a copper(II) metalloradical (L*CuII(carb')2) (L* = a monodentate chiral phosphine ligand; carb' = a carbazolide ligand), as well as a tertiary α-amide organic radical (R·); the generation and characterization of R· was guided by DFT calculations, which suggested that it would be stable to homocoupling. Continuous-wave (CW) and pulse EPR studies, along with corresponding DFT calculations, are among the techniques used to characterize these reactive radicals. We establish that these two radicals do indeed combine to furnish the C-N coupling product in good yield and with significant enantiomeric excess (77% yield, 55% ee), thereby supporting the chemical competence of these proposed intermediates. DFT calculations are consistent with R· initially binding to copper(II) via a dative interaction from the closed-shell carbonyl oxygen atom of the radical, which positions the α-carbon for direct reaction with the copper(II)-bound carbazole N atom, to generate the C-N bond with enantioselectivity, without the formation of an alkylcopper(III) intermediate.
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Conversion of dinitrogen to tris(trimethylsilyl)amine catalyzed by titanium triamido-amine complexes. Chem Commun (Camb) 2019; 55:3231-3234. [PMID: 30806394 DOI: 10.1039/c8cc09742a] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By using a triaryl-Tren ligated titanium dinitrogen complex, K2[{(Xy-N3N)Ti}2(μ2-N2)] (3), prepared by two-electron reduction of [TiCl(Xy-N3N)] (1-Cl) under N2 atmosphere, catalytic fixation of molecular nitrogen to form tris(trimethylsilyl)amine was achieved under ambient conditions with a turnover number (TON) of up to 16.5 per titanium atom.
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Cobalt Complexes Supported by cis-Macrocyclic Diphosphines: Synthesis, Reactivity, and Activity toward Coupling Carbon Dioxide and Ethylene. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Abstract
β-Diketiminate (BDI) ligands are widely used supporting ligands in modern organometallic chemistry and are capable of stabilizing various metal complexes in multiple oxidation states and coordination environments.
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Synthesis of Unsupported d1–dx Oxido-Bridged Heterobimetallic Complexes Containing VIV: A New Direction for Metal-to-Metal Charge Transfer. Inorg Chem 2015; 54:5322-8. [DOI: 10.1021/acs.inorgchem.5b00370] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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The titanium tris-anilide cation [Ti(N[tBu]Ar)3]+ stabilized as its perfluoro-tetra-phenylborate salt: structural characterization and synthesis in connection with redox activity of 4,4′-bipyridine dititanium complexes. Dalton Trans 2015; 44:6784-96. [DOI: 10.1039/c5dt00105f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A rare cationic d0 metal tris-amide complex, containing an intriguing pyramidal TiN3 core geometry, namely {Ti(N[tBu]Ar)3}+, is isolated as its [B(C6F5)4]− salt.
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Ferromagnetic coupling in d1–d3 linear oxido-bridged heterometallic complexes: ground-state models of metal-to-metal charge transfer excited states. Dalton Trans 2015; 44:18937-44. [PMID: 26466862 DOI: 10.1039/c5dt02719e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Linear heterobimetallic oxido-bridged d1–d3 compounds are described which are proposed as models for magnetic coupling of MMCT excited states.
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12
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Di(alkylamido)zirconium dichlorides and tri(arylamido)zirconium monochlorides having hemilabile N, O ligands and their methyl derivatives. J Organomet Chem 2015. [DOI: 10.1016/j.jorganchem.2014.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Mono-Oxido-Bridged Heterobimetallic and Heterotrimetallic Compounds Containing Titanium(IV) and Chromium(III). Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402800] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Role of Axial Base Coordination in Isonitrile Binding and Chalcogen Atom Transfer to Vanadium(III) Complexes. Inorg Chem 2014; 53:11185-96. [DOI: 10.1021/ic5017005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Methylene-Linked Anilide—Bis(aryloxide) Ligands: Lithium, Sodium, Potassium, Chromium(III), and Vanadium(III) Ligation. Inorg Chem 2014; 53:6775-87. [DOI: 10.1021/ic5005853] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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16
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Synthesis and Structural Characterization of a Novel Heterodinuclear Vanadium(IV)-Nickel(II) Complex. Z Anorg Allg Chem 2011. [DOI: 10.1002/zaac.201100428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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White Phosphorus Activation at a Metal–Phosphorus Triple Bond: a New Route to cyclo-Triphosphorus or cyclo-Pentaphosphorus Complexes of Niobium. Inorg Chem 2011; 50:12349-58. [DOI: 10.1021/ic2014607] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Reactivity Studies of a Masked Three-Coordinate Vanadium(II) Complex. Angew Chem Int Ed Engl 2010; 49:9871-5. [DOI: 10.1002/anie.201005029] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Properties and Reactivity Patterns of AsP3: An Experimental and Computational Study of Group 15 Elemental Molecules. J Am Chem Soc 2009; 131:15501-11. [DOI: 10.1021/ja906294m] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Synthesen und Strukturen der Lithiumtitanate(III) und -(IV), (py)2Li[(py)2Ti(OPh)4] und (py)2Li[(py)Ti(OPh)5]. Z Anorg Allg Chem 2009. [DOI: 10.1002/zaac.200800382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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A Rare η3 Binding Mode of Aryloxides in Iridium, Rhodium, and Ruthenium Complexes. Organometallics 2008. [DOI: 10.1021/om800985u] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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A Reactive Niobium Phosphinidene P8 Cluster Obtained by Reductive Coupling of White Phosphorus. Angew Chem Int Ed Engl 2008; 47:169-72. [DOI: 10.1002/anie.200704354] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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A Reactive Niobium Phosphinidene P8 Cluster Obtained by Reductive Coupling of White Phosphorus. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200704354] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Terminal, anionic carbide, nitride, and phosphide transition-metal complexes as synthetic entries to low-coordinate phosphorus derivatives. Angew Chem Int Ed Engl 2007; 45:862-70. [PMID: 16385612 DOI: 10.1002/anie.200503327] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anionic terminal one-atom nitride, phosphide, and carbide complexes are excellent starting materials for the synthesis of ligands containing low-coordinate phosphorus centers in the protecting coordination sphere of the metal complex. Salt-elimination reactions with chlorophosphanes lead to phosphaisocyanide, iminophosphinimide, and diorganophosphanylphosphinidene complexes in which the unusual phosphorus ligands are stabilized by coordination. X-ray structure analyses and density-functional calculations illuminate the bonding in these compounds.
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An Isolable and Monomeric Phosphorus Radical That Is Resonance-Stabilized by the Vanadium(IV/V) Redox Couple. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200700059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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An Isolable and Monomeric Phosphorus Radical That Is Resonance-Stabilized by the Vanadium(IV/V) Redox Couple. Angew Chem Int Ed Engl 2007; 46:3111-4. [PMID: 17351998 DOI: 10.1002/anie.200700059] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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29
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Three-Coordinate Complexes of “Hard” Ligands: Advances in Synthesis, Structure and Reactivity. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166482.ch7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Rationalizing the different products in the reaction of N2 with three-coordinate MoL3 complexes. Dalton Trans 2007:1939-47. [PMID: 17702174 DOI: 10.1039/b701050h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of N2 with three-coordinate MoL3 complexes is known to give rise to different products, N-MoL3, L3Mo-N-MoL3 or Mo2L6, depending on the nature of the ligand L. The energetics of the different reaction pathways are compared for L = NH2, NMe2, N((i)Pr)Ar and N((t)Bu)Ar (Ar = 3,5-C6H3Me2) using density functional methods in order to rationalize the experimental results. Overall, the exothermicity of each reaction pathway decreases as the ligand size increases, largely due to the increased steric crowding in the products compared to reactants. In the absence of steric strain, the formation of the metal-metal bonded dimer, Mo2L6, is the most exothermic pathway but this reaction shows the greatest sensitivity to ligand size varying from significantly exothermic, -403 kJ mol(-1) for L = NMe2, to endothermic, +78 kJ mol(-1) for L = N((t)Bu)Ar. For all four ligands, formation of N-MoL3 via cleavage of the N2 bridged dimer intermediate, L3Mo-N-N-MoL3, is strongly exothermic. However, in the presence of excess reactant MoL3, formation of the single atom-bridged complex L3Mo-N-MoL3 from N-MoL3 + MoL3 is both thermodynamically and kinetically favoured for L = NMe2 and N((i)Pr)Ar, in agreement with experiment. In the case of L = N((t)Bu)Ar, the greater steric bulk of the (t)Bu group results in a much less exothermic reaction and a calculated barrier of 66 kJ mol(-1) to formation of the L3Mo-N-MoL3 dimer. Consequently, for this ligand, the energetically and kinetically favoured product, consistent with the experimental data, is the nitride complex L3Mo-N.
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Optimizing Small Molecule Activation and Cleavage in Three-Coordinate M[N(R)Ar]3 Complexes. Inorg Chem 2006; 45:6851-9. [PMID: 16903742 DOI: 10.1021/ic051778u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sterically hindered, three-coordinate metal systems M[N(R)Ar]3 (R = tBu, iPr; Ar = 3,5-C6H3Me2) are known to bind and activate a number of fundamental diatomic molecules via a [Ar(R)N]3M-L-L-M[N(R)Ar]3 dimer intermediate. To predict which metals are most suitable for activating and cleaving small molecules such as N(2), NO, CO, and CN(-), the M-L bond energies in the L-M(NH2)3 (L = O, N, C) model complexes were calculated for a wide range of metals, oxidation states, and dn (n = 2-6) configurations. The strongest M-O, M-N, and M-C bonds occurred for the d2, d3, and d4 metals, respectively, and for these d(n) configurations, the M-C and M-O bonds were calculated to be stronger than the M-N bonds. For isoelectronic metals, the bond strengths were found to increase both down a group and to the left of a period. Both the calculated N-N bond lengths and activation barriers for N2 bond cleavage in the (H2N)3M-N-N-M(NH2)3 intermediate dimers were shown to follow the trends in the M-N bond energies. The three-coordinate complexes of Ta(II), W(III), and Nb(II) are predicted to deliver more favorable N2 cleavage reactions than the experimentally known Mo(III) system and the Re(III)Ta(III) dimer, [Ar(R)N]3Re-CO-Ta[N(R)Ar]3, is thermodynamically best suited for cleaving CO.
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U(SMes*)n, (n = 3, 4) and Ln(SMes*)3 (Ln = La, Ce, Pr, Nd): Lanthanide(III)/Actinide(III) Differentiation in Agostic Interactions and an Unprecedented η3 Ligation Mode of the Arylthiolate Ligand, from X-ray Diffraction and DFT Analysis. J Am Chem Soc 2006; 128:8790-802. [PMID: 16819872 DOI: 10.1021/ja0584830] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of U(NEt(2))(4) with HS-2,4,6-(t)Bu(3)C(6)H(2) (HSMes) gave U(SMes)(3)(NEt(2))(py) (1), whereas similar treatment of U[N(SiMe(3))SiMe(2)CH(2)][N(SiMe(3))(2)](2) afforded U(SMes)[N(SiMe(3))(2)](3) (2) and U(SMes)(3)[N(SiMe(3))(2)]. The first neutral homoleptic uranium(IV) thiolate to have been crystallographically characterized, U(SMes)(4) (4), was isolated from the reaction of U(BH(4))(4) and KSMes. The first homoleptic thiolate complex of uranium(III), U(SMes)(3) (5), was synthesized by protonolysis of U[N(SiMe(3))(2)](3) with HSMes in cyclohexane. The crystal structure of 5 exhibits the novel eta(3) ligation mode for the arylthiolate ligand. Comparison of the crystal structure of 5 with those of the isomorphous lanthanide congeners Ln(SMes)(3) (Ln = La, Ce, Pr, and Nd) indicates that the U-S, U-C(ipso)(), and U-C(ortho)() bond lengths are shorter than the corresponding ones in the 4f-element analogues, when taking into account the variation in the ionic radii of the metals. The distance between the uranium and the carbon atoms involved in the U...H-C epsilon agostic interaction of each thiolate ligand is shorter, by approximately 0.05 A, than that expected from a purely ionic bonding model. The lanthanide(III)/actinide(III) differentiation was analyzed by density functional theory (DFT). The nature of the M-S bond is shown to be ionic strongly polarized at the sulfur for M = U and iono-covalent (i.e. strongly ionic with low orbital interaction), for M = Ln. The strength of the U...H-C epsilon agostic interaction is proposed to be controlled by the maximization of the interaction between U(+) and S(-) under steric constraints. The eta(3) ligation mode of the arylthiolate ligand is also obtained from DFT.
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A Diamagnetic Dititanium(III) Paddlewheel Complex with No Direct Metal−Metal Bond. Inorg Chem 2006; 45:4328-30. [PMID: 16711677 DOI: 10.1021/ic0602650] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reaction of Ti[N(But)Ar]3 (Ar = 3,5-C6H3Me2 or Ar' = C6H5) with CO2 at -40 degrees C produces diamagmetic Ti(III) paddlewheel complexes with long Ti-Ti separations (>3.4 Angstrom), thus excluding direct Ti-Ti bonding. 1H NMR spectroscopy shows that the compounds are diamagnetic in solution in the temperature range of -65 to +70 degrees C. In the solid state, the diamagnetism was found to persist between 2 and 300 K. Calculations at the density functional theory level suggest that the diamagnetism results from antiferromagnetic coupling by superexchange through the ligand pi system.
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Anionische Übergangsmetallkomplexe mit terminalen Carbid-, Nitrid- und Phosphidliganden als Synthesebausteine für niederkoordinierte Phosphorverbindungen. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503327] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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36
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Synthesen und Strukturen der Titan(III)-siloxane [Ti(OSiPh3)3(thf)2] und [Ti(OSiPh3)3(py)2]. Z Anorg Allg Chem 2006. [DOI: 10.1002/zaac.200500359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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A niobaziridine hydride system for white phosphorus or dinitrogen activation and N- or P-atom transfer. Dalton Trans 2006:2161-8. [PMID: 16673028 DOI: 10.1039/b602530g] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This short review describes a breakthrough embodied by the synthesis of a niobaziridine hydride complex. This reactive entity reacts directly with white phosphorus to provide a bridging diphosphorus diniobium complex that upon reduction splits to afford a terminal niobium phosphide anion, isolated as its sodium salt. Reactions of the latter with acid chlorides constitute a new synthesis of phosphaalkynes, while treatment with chlorodiorganophosphanes leads to complexed 1,1-diorganophosphanylphosphinidene systems. Additionally, reactions of the sodium salt of the niobium phosphide anion with divalent main group element salts (E = Ge, Sn, or Pb) provide complexed triatomic EP2 triangles. Dinitrogen cleavage was realized via reduction of a heterodinuclear niobium/molybdenum dinitrogen complex, and this provided an entry to a nitrogen-15 labeled terminal nitride anion of niobium as its sodium salt. In a fashion analogous to the aforementioned phosphaalkyne synthesis, acid chlorides are transformed upon reaction with the niobium nitride anion into corresponding nitrogen-15 labeled organic nitriles. Complete synthetic cycles are achieved in both the phosphaalkyne and the organic nitrile syntheses, as the oxoniobium(v) byproduct can be recycled in high yield to the title niobaziridine hydride complex.
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Synthesis of a four-coordinate titanium(iv) oxoanion via deprotonation and decarbonylation of complexed formate. Chem Commun (Camb) 2005:3403-5. [PMID: 15997278 DOI: 10.1039/b504492h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Deprotonation of the titanium formate complex [Ar(t-Bu)N]3TiOC(O)H with LiN(i-Pr)2 resulted in the release of free CO and the formation of a titanium(IV) oxoanion complex, isolated as its lithium salt.
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Non-cyclopentadienyl Titanium(III)−Magnesium Hydride Formation by Reduction of an Amidotitanium(IV) Complex. Organometallics 2003. [DOI: 10.1021/om034164a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Radical Scission of Symmetrical 1,4-Dicarbonyl Compounds: C−C Bond Cleavage with Titanium(IV) Enolate Formation and Related Reactions. Organometallics 2002. [DOI: 10.1021/om0107284] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Electronic Structure and Bonding in Tricoordinate Amido Complexes of Transition Metals. Inorg Chem 1999. [DOI: 10.1021/ic980634v] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Synthesis of mer-trichlorotris(tetrahydrofuran) tungsten(III) by intermetal chlorine atom transfer. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)06157-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Syntheses and structure of dimeric yttrium tris [bis(trimethylsilyl) phosphanide]; X-ray structures of [(thf)LiCl·(thf)2LiPtBu2]2 and Y[CH(SiMe3)2]3. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)05776-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Oxidation Reactions of [(Me3Si)2N]2VX(THF) (X = Cl, Me, Ph) with CuCl, PhCH(O)CH2, and Ph2CN2 and the Syntheses and Structures of the Vanadium(III) Anions {[(Me3Si)2N]2VX2}- (X = Cl, Me). Organometallics 1997. [DOI: 10.1021/om970458i] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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