A Structural Study of Bisphosphonate Metal Complexes − Three New Polymeric Structures of the Calcium Complex of Clodronic Acid

Autor: Markku Ahlgrén, Mervi Kontturi, Jouko Vepsäläinen, Sirpa Peräniemi
Rok vydání: 2004
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2004:2627-2631
ISSN: 1099-0682
1434-1948
Popis: Three novel calcium complexes of clodronic acid were prepared and their structures determined by single-crystal X-ray diffractometry. Previously, a monomeric structure, [Ca{Cl2C(PO3H)2}(H2O)5] (1), has been determined, but the new structures are polymeric: [{Ca2[Cl2C(PO3)2](H2O)6}·4.5H2O]n (2), [{Ca2Na0.5[Cl2C(PO3)2](H2O)8}Cl0.5·4H2O]n (3) and [{Ca5[Cl2C(PO3)2]2(H2O)15}(NO3)2·1.5H2O]n (4); and they provide new, important information about the binding abilities of clodronic acid. Compounds 2−4 crystallise in the triclinic crystal system, the space group being P with Z = 2. Compound 2 consists of Ca atoms and Cl2MBP ligands connected to one-dimensional chains. The chains are held together by hydrogen bonds formed by aqua ligands and lattice water molecules. The structure of 3 consists of similar calcium clodronate chains forming two-dimensional layers through additional, six-coordinate Na atoms. Compound 4 consists of two-dimensional calcium clodronate layers, the calcium atoms are connected by Cl2MBP− and aqua ligands. The nitrate groups and lattice water molecules lie between the layers and hold them together. The layered compounds 3 and 4 reveal substantial porosity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Databáze: OpenAIRE
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