N,N′-ethylenebis(acetylacetoneiminato)titanium complexes: synthesis, crystal structures, and properties of titanium(III) and titanium(IV) derivatives

Abstract

The reaction of TiCl₄·2thf and TiCl₃·3thf (thf = tetrahydrofuran) with the Na₂acen [acen =N,N′-ethylenebis(acetylacetoneiminate) dianion] gave the corresponding titanium (IV), [Ti(acen)Cl₂](1), and titanium(III), [Ti(acen)Cl(thf)](2), derivatives in good yield. Complex (2) has a d¹ configuration and is easily oxidized to titanium (IV) derivatives. Reaction with oxygen afforded a µ-oxo complex [Cl(acen)TiOTi(acen)Cl], (3), having a linear Ti–O–Ti skeleton [Ti–O 1.813(1)Å; ν(Ti–O) 750 cm^–1]. The structures of complexes (1)–(3) have been determined by X-ray analysis: (1) space group P2₁/n(monoclinic), a= 27.510(9), b= 14.347(5), c= 7.839(3)Å, β= 94.52(1)°, Z= 8, and R= 0.050 for 1 737 observed reflections; (2), space group P2₁2₁2₁(orthorhombic), a=15.403(2), b= 14.883(2), c= 8.180(l)Å, Z= 4, and R= 0.043 for 2 085 observed reflections; (3), space group P2₁/n(monoclinic), a= 10.599(2), b= 18.392(5), c= 7.551(2)Å, β= 101.90(2°), Z= 2, and R= 0.031 for 1 961 observed reflections.