Structure and Spectroscopic Studies of Cd(II) Complexes of Tris(2-pyridyl)amine: 1D and 2D Supramolecular Assemblies

Abstract

Cd(II) halide complexes [Cd2X4(tpa)2] (1: X = Cl, 2: X = Br, 3: X = I; tpa = tris(2-pyridyl)amine) have been synthesized. X-Ray diffraction analyses of 2 and 3 reveal their asymmetrical dinuclear structures: one Cd(II) atom is octahedrally coordinated to four N atoms of two tpa ligands and two bridging halides; the other Cd(II) is tetrahedrally coordinated to two terminal (X(t)) and two bridging (X(b)) halides. By multiple intra- and intermolecular π-π interactions between the tpa pyridine rings, the ligands of 2 and 3 are linked to form a 2D network and 1D linear structures, respectively. In the Raman and far-infrared spectra, the absorption bands due to Cd-X(b) stretching modes lie at lower wavenumbers compared to the Cd-X(t) stretches. It can be inferred from the spectroscopic data that 1 has a dinuclear structure similar to those of 2 and 3.