A Mononuclear and High-Spin Tetrahedral TiII Complex.

摘要: A high-spin, mononuclear TiII complex, [(TptBu,Me)TiCl] [TptBu,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 [(TptBu,Me)TiCl2] with KC8. Complex 3A2 ground state (assuming C3v symmetry based on structural studies), established via combination high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy, solution solid-state magnetic studies, Ti K-edge X-ray absorption spectroscopy (XAS), both density functional theory ab initio (complete-active-space self-consistent-field, CASSCF) calculations. The formally physically defined complex readily binds tetrahydrofuran (THF) form adduct [(TptBu,Me)TiCl(THF)], which is impervious N2 binding. However, in absence THF, captures produce diamagnetic [(TptBu,Me)TiCl]2(η1,η1;μ2-N2), linear Ti═N═N═Ti topology, single-crystal diffraction. was characterized using XAS as well IR Raman spectroscopies, thus establishing this possess two TiIII centers covalently bridged an N22- unit. π acid such CNAd (Ad 1-adamantyl) coordinates without inducing spin pairing d electrons, thereby forming unique high-spin five-coordinate namely, [(TptBu,Me)TiCl(CNAd)]. reducing power coordinatively unsaturated TiII-containing [(ΤptBu,Me)TiCl] species, quantified electrochemistry, provides access family TiIV complexes type [(TptBu,Me)Ti═E(Cl)] (with E2- NSiMe3, N2CPh2, O, NH) virtue atom- or group-transfer reactions various small molecules N3SiMe3, N2O, bicyclic amine 2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene.