Electronic Structure and Reactivity of a Well-Defined Mononuclear Complex of Ti(II)

Academic Article

Abstract

  • A facile and high-yielding protocol to the known Ti(II) complex trans-[(py)4TiCl2] (py = pyridine) has been developed. Its electronic structure has been probed experimentally using magnetic susceptibility, magnetic circular dichroism, and high-frequency and high-field electron paramagnetic resonance spectroscopies in conjunction with ligand-field theory and computational methods (density functional theory and ab initio methods). These studies demonstrated that trans-[(py)4TiCl2] has a 3Eg ground state (dxy1dxz,yz1 orbital occupancy), which, as a result of spin-orbit coupling, yields a ground-state spinor doublet that is EPR active, a first excited-state doublet at ∼60 cm-1, and two next excited states at ∼120 cm-1. Reactivity studies with various unsaturated substrates are also presented in this study, which show that the Ti(II) center allows oxidative addition likely via formation of [Ti(η2-R2E2)Cl2(py)n] E = C, N intermediates. A new Ti(IV) compound, mer-[(py)3(η2-Ph2C2)TiCl2], was prepared by reaction with Ph2C2, along with the previously reported complex trans-(py)3Ti=NPh(Cl)2, from reaction with Ph2N2. Reaction with Ph2CN2 also yielded a new dinuclear Ti(IV) complex, [(py)2(Cl)2Ti(μ2:η2-N2CPh2)2Ti(Cl)2], in which the two Ti(IV) ions are inequivalently coordinated. Reaction with cyclooctatetraene (COT) yielded a new Ti(III) complex, [(py)2Ti(η8-COT)Cl], which is a rare example of a mononuclear "piano-stool" titanium complex. The complex trans-[(py)4TiCl2] has thus been shown to be synthetically accessible, have an interesting electronic structure, and be reactive toward oxidation chemistry.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Wijeratne GB; Zolnhofer EM; Fortier S; Grant LN; Carroll PJ; Chen CH; Meyer K; Krzystek J; Ozarowski A; Jackson TA
  • Start Page

  • 10380
  • End Page

  • 10397
  • Volume

  • 54
  • Issue

  • 21