title: Structures of bisphosphonate metal complexes: zinc and cadmium complexes of clodronate and its partial ester derivatives.
abstract: Four new zinc and cadmium bisphosphonates [{NaZn(Cl2CP2O6H)(H2O)5}]n (1), [{Cd2(Cl2CP2O6)(H2O)4}.H2O]n (2), [{Zn(Cl2CP2O6Pri2)(H2O)3}.H2O]n (3), and [{Cd2(Cl2CP2O6Pri2)2(MeOH)2(H2O)2}.H2O]2 (4) have been prepared and their crystal structures determined by single-crystal X-ray diffractometry. Two bisphosphonate ligands were used: clodronate, (dichloromethylene)bis(phosphonate) and its symmetrical P,P'-diisopropyl ester derivative. The structure of the Zn complex 1 is three-dimensional, consisting of one-dimensional Zn-clodronate chains connected to the three-dimensional network by Na+ ions. The structure of Cd complex 2 consists of double layers, and a unique bond was found between the Cd2+ cation and a Cl atom of clodronate. Zn complex 3 consists of one-dimensional chains, but the binding of the bisphosphonate ligands is unique: in 3 the bisphosphonate ligand is only bidentate. Compound 4 is a tetramer, and hydrogen bonds hold the tetramers together, forming a layered structure.
authors.affiliation: Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland. mervi.kontturi@joensuu.fi
authors.forename: Mervi
authors.initials: M
authors.lastname: Kontturi
authors.forename: Elina
authors.initials: E
authors.lastname: Laurila
authors.forename: Riikka
authors.initials: R
authors.lastname: Mattsson
authors.forename: Sirpa
authors.initials: S
authors.lastname: Peräniemi
authors.forename: Jouko J
authors.initials: JJ
authors.lastname: Vepsäläinen
authors.forename: Markku
authors.initials: M
authors.lastname: Ahlgrén