Complexes of substituted benzothiazoles. 2. Copper(II) complexes of the 'tripod' ligand tris(2-benzothiazolylmethyl)amine

Abstract

A series of copper(II) complexes of the title ligand are reported which exhibit both five-coordinate trigonal bipyramidal and pseudo-octahedral stereochemistries. Mixed stereochemistry complexes [Cu(NTBT)X]2[CuX4] (X = Cl, Br), [Cu(NTBT)Br]2[Cu2Br6]•CH3CN, and the complexes [Formula: see text], [Formula: see text], contain trigonal bipyramidal cations while six-coordinate structures are implicated in the Systems [Cu(NTBT)Br2]•H2O and [Cu(NTBT)(H2O)2•MeOH•H2O. The molecular structure of [Formula: see text] has been determined by single crystal X-ray diffractometry. The crystal is monoclinic and belongs to the space group C2/c with Z = 8, a = 24.254(3), b = 14.107(2), c = 16.329(2) Å and β = 105.94(1)°. The complex adopts a distorted trigonal bipyramidal structure (no axial symmetry) with the ligand coordinating in a 'tripod' fashion as an N4 donor. The fifth ligand is a monodentate nitrate. The mean Cu—N distance is 2.07(3) Å and the Cu—O distance is 1.938(3) Å. A second nitrate oxygen atom is close to the copper centre (Cu—O distance 2.783(4) Å) and may represent a weakly bound sixth ligand. Both infrared and electronic spectral data support the presence of a sixth ligand.