Structures, magnetic properties, and XPS of one-dimensional cyanide-bridged Cu-II-Ni-II/Pt-II bimetallic assembly complexes

摘要

Synthesis, crystal structures, and spectroscopic and magnetic properties of new one-dimensional cyano-bridged bimetallic complexes, [Cu-II(N-Eten)(2)][M-II(CN)(4)] (N-Eten = N-ethylethylenediamine; M-II = Ni-II (1) and Pill (2)), have been reported. Both complexes consist of one-dimensional alternate chains of Cu-II and M-II moieties. The Pt-C bond distances of 1.997(3) and 2.001(3) angstrom for 2 are considerably longer than the Ni-C bond lengths of 1.866(3) and 1.872(3) angstrom for 1. Because of pseudo Jahn-Teller distortion, the axial Cu-N bond distances of 2.554(2) and 2.550(3) angstrom for I and 2 are longer than those of equatorial ones of 2.008(2) and 2.056(2) angstrom for 1 and 2.010(2) and 2.054(2) angstrom for 2. In contrast to M-II-C bond distances, the Cu-N ones of 1 are similar to those of 2 regardless of element-substitution. These complexes indicate weak antiferromagnetic interactions with Weiss constants = -4.68 and -3.95 K for 1 and 2, respectively. The emission spectrum of 2 (lambda(eX) = 360 nm) exhibits a broad band with peaks at 22800 and 24000 cm(-1) at 298 K. The Cu 2p(1/2) and 213(3/2) peaks of XPS spectra are compared systematically to various copper(II) complexes showing different bridging features or distorted coordination geometries as models for excited structures induced by external physical conditions. The spectroscopic properties are discussed from the viewpoint of magneto-optical properties. (c) 2006 Elsevier B.V. All rights reserved.