Synthesis and Reactivity of Titanium Hydrazido Complexes Supported by Diamido-Ether Ligands

The synthesis and reactivity of titanium diphenyl hydrazido(2) complexes supported by the diamido-ether ligands O(2-C6H4NSiMe3)(2) ((N2O)-O-Ar) and O-(CH2CH2NSiMe3)(2) (N2O) are described. Reaction of (Li2N2O)-O-Ar or Li2N2O with Ti(NNPh2)Cl-2(PY)(3) afforded Ti((N2O)-O-Ar)(NNPh2)(py)(2) (14) or Ti(N2O)(NNPh2)(py)(2) (15) with kappa(3)-mer-bound diamida-ether ligands. Reaction with 'Bu-bipy (4,4'-di-tert-butyl-2,2'-bipyridyl) or bipy (2,2'-bipyridyl) gave a switch to kappa(3)-fac-coordination. Reaction of 15 with Ar'NCO (Ar' = 2,6-(C6H3Pr2)-Pr-i) gave Ti{0(CH2CH2NSiMe3)(CH2CH2NC(O)N(SiMe3)Ar'}-{N(NPh2)C(O)N(Ar')), in which the substrate has inserted into a Ti-N-amide bond of N2O as well as adding to the Ti=N-alpha multiple bond. With Ar'NCS the [2+2] cydoaddition product Ti(N2O){N(NPh2)C(NAr')S)(py) was obtained, and with Ar'NCSe a mixture was formed including Ti-2(N2O)(2)(mu-Se)(2). Both 14 and 15 reacted with (ArCN)-C-Fx (Ar-Fx = C6H3F2 or C6F5) to give Ti=Na bond insertion products of the type Ti(L){NC(Ar-Fx)NNPh2}(py)(2) (L = (N2O)-O-Ar or N2O) containing hydrazonamide ligands. Reaction of 14 with XyINC (Xyl = 2,6-C6H3Me2) gave only the isonitrile sigma-adduct Ti(N2ArO)(NNFh(2))(PMCNXyl), whereas 15 underwent N-alpha-N-beta bond reductive cleavage with (BuNC)-Bu-t or XyINC forming Ti(N2O)(NPh2)((NCNBu)-Bu-t) or Ti{O(CH2CH2NSiMe3)(CH2CH2NCN(SiMe3)Xyl)}(NPh2)(NCNXyl) (27). Both contain metalated carbodiimide ligands, but in 27 an additional reaction of XylNC with the Ti-N-amide bond of N2O has taken place. Compound 15 also reacted with a number of internal alkynes RCCR' (R = R' = Me or Ph; R = Me, R' = aryl) to give N-alpha-N-beta bond reductive cleavage products of the type Ti{O(CH2CH2NSiMe3)(CH2CH2NC(R)C(R')NSiMe3}(NPh2), again involving a reaction of a Ti-N-amide bond.