A Mononuclear and High-Spin Tetrahedral TiII Complex
| Autor: | Karsten Meyer, Ida M. DiMucci, Joshua Telser, Daniel Pividori, Andrew Ozarowski, Mehrafshan G. Jafari, Patrick J. Carroll, J. Krzystek, Michael R. Gau, Daniel J. Mindiola, Alexander L Laughlin, Samantha N. MacMillan, Kyle M. Lancaster, Anders Reinholdt |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Bicyclic molecule
Absorption spectroscopy 010405 organic chemistry Ab initio 010402 general chemistry 01 natural sciences 0104 chemical sciences Adduct law.invention Inorganic Chemistry chemistry.chemical_compound Crystallography Paramagnetism chemistry law Density functional theory Physical and Theoretical Chemistry Electron paramagnetic resonance Tetrahydrofuran |
| Zdroj: | Inorg Chem |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/acs.inorgchem.0c02586 |
| Popis: | [Image: see text] A high-spin, mononuclear Ti(II) complex, [(Tp(tBu,Me))TiCl] [Tp(tBu,Me–) = hydridotris(3-tert-butyl-5-methylpyrazol-1-yl)borate], confined to a tetrahedral ligand-field environment, has been prepared by reduction of the precursor [(Tp(tBu,Me))TiCl(2)] with KC(8). Complex [(Tp(tBu,Me))TiCl] has a (3)A(2) ground state (assuming C(3v) symmetry based on structural studies), established via a combination of high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy, solution and solid-state magnetic studies, Ti K-edge X-ray absorption spectroscopy (XAS), and both density functional theory and ab initio (complete-active-space self-consistent-field, CASSCF) calculations. The formally and physically defined Ti(II) complex readily binds tetrahydrofuran (THF) to form the paramagnetic adduct [(Tp(tBu,Me))TiCl(THF)], which is impervious to N(2) binding. However, in the absence of THF, the Ti(II) complex captures N(2) to produce the diamagnetic complex [(Tp(tBu,Me))TiCl](2)(η(1),η(1);μ(2)-N(2)), with a linear Ti=N=N=Ti topology, established by single-crystal X-ray diffraction. The N(2) complex was characterized using XAS as well as IR and Raman spectroscopies, thus establishing this complex to possess two Ti(III) centers covalently bridged by an N(2)(2–) unit. A π acid such as CNAd (Ad = 1-adamantyl) coordinates to [(Tp(tBu,Me))TiCl] without inducing spin pairing of the d electrons, thereby forming a unique high-spin and five-coordinate Ti(II) complex, namely, [(Tp(tBu,Me))TiCl(CNAd)]. The reducing power of the coordinatively unsaturated Ti(II)-containing [(Τp(tBu,Me))TiCl] species, quantified by electrochemistry, provides access to a family of mononuclear Ti(IV) complexes of the type [(Tp(tBu,Me))Ti=E(Cl)] (with E(2–) = NSiMe(3), N(2)CPh(2), O, and NH) by virtue of atom- or group-transfer reactions using various small molecules such as N(3)SiMe(3), N(2)CPh(2), N(2)O, and the bicyclic amine 2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|