Copper phosphonates with dinuclear and layer structures: a structural and magnetic study

摘要

Hydrothermal reactions of copper (II) nitrate with 1-hydroxycyclohexanephosphonic acid [C6H10(OH)PO3H2] or Delta(1)-cyclohexenephosphonic acid [C6H9PO3H2] have resulted in three new copper phosphonates, namely, Cu(C6H10(OH)PO3)(H2O)(2) (1), Cu(C6H10(OH)PO3) (2) and Cu(C6H9PO3)(H2O) (3). Compound 1 has a dinuclear structure in which two {CuO5} square pyramids are bridged by two {CPO3} tetrahedra through corner sharing. The dimers are connected through intermolecular hydrogen bonds, forming supramolecular layers. Both compounds 2 and 3 show layer structures typical for metal mono-phosphonates, in which the inorganic metal-containing layers are separated by cyclohexane or cyclohexene groups. The magnetic studies show that ferromagnetic interactions are mediated between copper centers in compound 1. In compounds 2 and 3, antiferromagnetic interactions are dominant. (C) 2004 Elsevier Inc. All rights reserved.