Preparations and structures of NN′-ethylenebis(salicylideneiminato)-titanium(III) derivatives

Abstract

Reduction of [Ti (salen) Cl₂,][salen =NN′-ethylenebis(salicylideneiminate)] with zinc dust in tetrahydrofuran (thf) gives deep blue solutions from which dimeric [{Ti(salen)(thf)}₂][ZnCl₄] is obtained. The reduced paramagnetism (µ_eff 0.96 B.M., 293 K) of this complex suggests a strong electronic interaction between two metal centres. The same solution, when treated with pyridine (py), leads to the very air-sensitive [Ti(salen) Cl (py)]· thf whose magnetic moment (µ_eff. 1.79 B.M. at 293 K) corresponds to that expected for a d¹ system. X-Ray analysis of this complex confirms the pseudo-octahedral co-ordination around titanium, with the salen unit in the equatorial plane and Cl and py trans to each other in the axial positions. The crystal structure has been solved by the heavy-atom technique and refined by anisotropic least-squares methods to a final R of 0.066. The crystals are monoclinic, space group P2₁/_c. with a= 9.828(2), b= 19.508(5), c= 13.465(2)Å, β= 109.5(4)°, U= 2 440(2)ų, and Z= 4.