catena-μ-Perchlorato-O,O'-tris-μ-quinoxaline-N,N'-dicopper(I) perchlorate: structure and infrared spectrum

Abstract

Abstract.[Cu2(CsH6N2)3(C104)](C104) , Mr=716"4, monoclinic, P2~, a=8.952 (2), b= 14.573 (4), c= 9.912 (3)/~, fl= 94.61 (2) ° , V= 1288.9 (5)/~3 Om = 1.846 (5), D x = 1.85 gcm -3, Z = 2, ,;I,(Mo Ka) = 0.71069,/k, g(MoKa)=19.3cm -1, F(000)=720, T = 295 K, final refinement on F [2520 data with Fo> 6a(Fo), 20max= 55.00] • R =0.048, wR =0.049. The polymeric structure of the title compound consists of a three-dimensional net with all three quinoxaline molecules and one perchlorate ion forming bridges between Cu atoms. The coordination sphere of both Cu atoms is a distorted tetrahedron. The IR spectrum shows bands typical for bridging quinoxaline and perchlorate.

Structure of catena-bis[μ-chloro-chloro-μ-quinoxaline-N,N'-copper(II)]

“…The dihedral angle is 4.9 (5) ° . The bond lengths and angles in the quinoxaline molecule are similar to those measured in other structures (Lumme, Lindroos & Lindell, 1987, 1988Padmaja, Ramakumar & Viswamitra, 1987;Lipkowski, Andreetti & Sgarabotto, 1977). The coordination polyhedron of copper(II) is a square bipyramid with four dioximate N atoms in the equatorial plane and two thiourea S atoms in axial positions, in contrast with the pentacoordinate copper dioximate complexes reported so far.…”

“…Quinoxaline, like other nitrogen heterocycles with two N atoms in the molecule, has a tendency to form polymeric structures in which quinoxaline forms a bridge between two metal atoms (Lumme, Lindroos & Lindell, 1987;Richardson, Hatfield, Stoklosa & Wasson, 1973).…”

Chemistry of the copper(I)–water bond. Some new observations

“…We now mention that earlier work with unsubstituted quinoxaline (Q), a polymeric copper(I) complex of the type {[Cu(Q) 3 ClO 4 ]ClO 4 } n , in which the bridging Q moieties give rise to a three dimensional network, has been reported. 19 Some structurally uncharacterised polymeric copper(II) complexes of the type CuX 2 (L or L 0 ) with X ¼ Cl À , Br À and NO 3…”

Syntheses, Crystal Structures and Adsorption Properties of Ultramicroporous Coordination Polymers Constructed from Hexafluorosilicate Ions and Pyrazine

“…[45] Actually, the pH of the supernatant solution of 1c is 2.1, suggesting that high temperature promotes this pathway in our case. This mechanism also might be applicable for providing several Cu(I/II) mixed-valence compounds [46][47][48][49][50][51] and Cu I coordination polymers; [52][53][54][55][56][57] high temperatures with py-X-py-type ligands probably assist in the reduction of Cu II to Cu I .…”