Formate complexes of titanium(IV) supported by a tris(phenolato)-amine ligand

Abstract The synthesis of terminal and bridging formate complexes of titanium(IV) stabilized by a tris(phenolato)-amine ligand is described. The terminal formate complex [(O 3 N)Ti(OCHO)] (H 3 (O 3 N) = tris(4,6-di- tert -butyl-2-hydroxybenzyl)amine) was synthesized by salt metathesis of the chloride precursor [(O 3 N)TiCl] with sodium formate. Reaction of the terminal formate with the cationic titanium(IV) complex [(O 3 N)Ti(Et 2 O)][B(C 6 F 5 ) 4 ], synthesized by protonolysis of the benzyl complex [(O 3 N)Ti(CH 2 Ph)] with [PhMe 2 NH][B(C 6 F 5 ) 4 ] gave the bridging formate complex [{(O 3 N)Ti} 2 (μ-OCHO–η O :η O ′)][B(C 6 F 5 ) 4 ] that was structurally characterized by single crystal X-ray diffraction. Attempts at deprotonation of the formate ligand by KHMDS (HMDS = N(SiMe 3 ) 2 ) to give the CO 2 dianion failed but led to the formation of [(O 3 N)Ti{N(SiMe 3 ) 2 }] instead.