Titanium Imido Complexes Supported by Amidinate Ligands: Synthesis, Solution Dynamics, and Solid State Structures.
Reaction of Li[PhC(NSiMe(3))(2)] with the complexes [Ti(NR)Cl(2)(py)(3)] affords the corresponding (N,N'-bis(trimethylsilyl)benzamidinato)titanium imido derivatives [Ti(NR){PhC(NSiMe(3))(2)}Cl(py)(2)] [R = Bu(t) (1), 2,6-C(6)H(3)Me(2) (2), 2,6-C(6)H(3)Pr(i)(2) (3)], which, in solution, exist in temperature-dependent, dynamic equilibrium with their mono(pyridine) homologues [Ti(NR){PhC(NSiMe(3))(2)}Cl(py)] and free pyridine. Kinetic and thermodynamic data for these processes are reported, and the relative contributions of the DeltaH and DeltaS terms associated with all three equilibria are identified. The arylimido complexes 2 and 3 may also be prepared by treating 1 with the appropriate arylamine. Reaction of Li[MeC(NC(6)H(11))(2)] with [Ti(NBu(t))Cl(2)(py)(3)] gives the binuclear N,N'-bis(cyclohexyl)acetamidinato derivative [Ti(2)(&mgr;-NBu(t))(2){MeC(NC(6)H(11))(2)}(2)Cl(2)] (4). The X-ray structures of 2 and 4 have been determined. Crystal data for 2: triclinic, P&onemacr;, a = 11.219(5) Å, b = 12.131(6) Å, c = 13.208(7) Å, alpha = 80.34(5) degrees, beta = 87.41(4) degrees, gamma = 75.13(3) degrees, V = 1722.1(15) Å(3), Z = 2, R = 0.054, R(w) = 0.056. Crystal data for 4: triclinic, P&onemacr;, a = 10.455(3) Å, b = 10.637(5) Å, c = 11.024(3) Å, alpha = 90.52(4) degrees, beta = 112.62(3) degrees, gamma = 114.10(3) degrees, V = 1012.8(10) Å(3), Z = 1, R = 0.0453, R(w) = 0.0495.
Stewart
Peter J.
PJ
Department of Chemistry, University of Nottingham, Nottingham NG7 2RD, U.K.
Blake
Alexander J.
AJ
Mountford
Philip
P