X-ray diffraction study of bisphosphonate metal complexes: Mg and Ca complexes of (dichloromethylene)bisphosphonic acid P,P '-diisopropyl ester

摘要

Mg(II) and Ca(II) complexes of a (dichloromethylene)bisphosphosphonic acid P,P'-diisopropyl ester: [Na2Mg{Cl2C(PO(3)iPr)(2) (2)(H2O)(4)](n) (1) and [{Ca-2[Cl2C(PO(3)iPr)(2)](2)(EtOH)(2)(H2O)(2)} . H2O](2) (2) were prepared and characterised by X-ray crystallography. Compound 1 contains two independent octahedral Mg atoms at the centres of symmetry and two five-coordinated Na atoms between them, connected to polymeric chains along the c-direction by chelating and bridging bisphosphonato ligands. Compound 2 is a tetramer possessing a centre of symmetry; the Ca atoms are connected to each other by chelating and bridging bisphosphonato ligands. Compounds 1 and 2 form layers through hydrogen bonds. (C) 2004 Elsevier Ltd. All rights reserved.