Alkoxo-bridged binuclear copper(II) complexes as nodes in constructing extended structures

Abstract

Three new compounds exhibiting extended structures have been obtained by using alkoxo-bridged binuclear copper(II) complexes as nodes, and bis(4-pyridyl) derivatives as spacers: [Cu 2(H 2tea) 2(bpe)](ClO 4) 2·(bpe)·H 2O ( 1), [Cu 2(Hdea) 2(4,4′-bipy)](ClO 4) 2 ( 2), and [Cu 2(ap) 2(4,4′-bipy) 2](ClO 4) 3·(4,4′-bipy)·(H 2ap)·(H 2O) ( 3) (H 3tea=triethanolamine, H 2dea=diethanolamine, Hap=aminopropanol; bpe= trans-1,2-bis(4-pyridyl)ethylene, 4,4′-bipy=4,4′-bipyridine). The structure of 1 consists of infinite chains resulted by connecting the bis(alkoxo)-bridged unsymmetrical [Cu 2(H 2tea) 2] 2+ nodes with bis(4-pyridyl)ethylene rods. The Cu⋯Cu separations are of 2.924 and 13.402 Å in an alternate mode. The noncoordinated bpe molecules bind the parallel coordination polymer chains, spread along b axis, through intermolecular H-bonds, resulting in a double zigzag ladder network. In crystal 2, the 4,4′-bipy molecules connect centrosymmetric [Cu 2(Hdea) 2] 2+ nodes, resulting in infinite chains. The parallel chains are disposed in planes which are parallel to the ab crystallographic plane. The chains directions, [110] or [1−10], alternate in adjacent planes. The stereochemistry of the copper(II) ion is distorted square-pyramidal. The alternate Cu⋯Cu distances within the chain are: 2.9880(5) and 11.0310(5) Å. Compound 3 is a two-dimensional coordination polymer. There are two crystallographically independent centrosymmetric [Cu 2(ap) 2] cores. The distances between the alkoxo-bridged copper atoms within the nodes are: 3.071(2) and 3.036(2) Å. Each node is connected through four 4,4′-bipy bridges to four other nodes, resulting in a two-dimensional layer with rhombic meshes. The dimensions of the rhomboidal cells are 12.31 and 13.36 Å, with an angle between the edges of 83.4°. The uncoordinated 4,4′-bipy and water molecules, the H 2pa + (monoprotonated aminopropanol species) and perchlorate ions are interconnected through hydrogen bonds resulting in infinite chains. These hydrogen-bonded polymers fill the channels resulted through the stacking of the 2-D layers.