A three dimensional network of Cadmium"

Abstract

In attempts to build molecular materials with interesting properties, such as catalysis clathration etc., much attention has been given to the synthesis of one-, two- and three-dimensional extended solids involving cadmium. Rigid bridged ligands are frequently employed to construct these materials (Abrahams et al., 1994[Abrahams, B. F., Hardie, M. J., Hoskins, B. F., Robson, R. & Sutherland, E. E. (1994). J. Chem. Soc. Chem. Commun. pp. 1049-1050.]; Soma et al., 1994[Soma, T., Yuge, H. & Iwamoto, T. (1994). Angew. Chem. Int. Ed. Engl. 33, 1665-1666.]; Fujita et al., 1994[Fujita, M., Kwon, Y. J., Miy­aza­wa, M. & Ogura, K. (1994). J. Chem. Soc. Chem. Commun. pp. 1977-1978.]; Yuge & Iwamoto, 1995[Yuge, H. & Iwamoto, T. (1995). Acta Cryst. C51, 374-377.]). The ambidentate thio­cyanate ion which is usually S-bonded to a soft and N-bonded to a hard metal centre can also act as a bridging bidentate ligand to satisfy the coordination number of the metal ion, although the thio­cyanate anion has not been widely used in the construction of inorganic polymeric networks. In order to synthesize uncharged three-dimensional polymers where channels remain unblocked by anions and free for solvent inclusion, we have chosen cadmium(II) thio­cyanate as an effective building block. Cadmium is well suited to this as its d10 configuration permits a wide variety of symmetries and coordination numbers. Recently, we reported the syntheses of the inorganic polymer [Cd3(dien)2(μ-NCS)6]n·nH2O (dien is diethyl­enetri­amine), (II[link]) (Mondal et al., 1999[Mondal, A., Mostafa, G., Ghosh, A., Laskar, I. R. & Ray Chaudhuri, N. (1999). J. Chem. Soc. Dalton Trans. pp. 9-10.]), which utilizes the full bridging potential of the anion. The structure of complex (II[link]) is a polymeric network which contains solvent-filled channels. Channel-containing solids have been and continue to be investigated intensively because of their potential applications, viz. as heterogeneous catalysts and molecular sieves. As part of a continuing investigation into control over the channels, we are currently studying the corresponding cadmium compounds. In this paper, we report the structure of the title CdII complex (I[link]), where medien [medien is N,N-bis(2-amino­ethyl)­methyl­amine] ligands replace the dien ligands of complex