Unprecedented deca-, penta- and poly-heteronuclear complexes with hexacyanometallates and 2-(hydroxymethyl)pyridine

Abstract

The reactions of hexacyanometallates (Fe(III) and Co(III)) and 2-(hydroxymethyl)pyridine (hmpy) with ZnCl2 and CdCl2 affords the decanuclear [Cd6(hmpy)12Fe2(μ-CN)8(CN)4Fe2(μ-CN)4(CN)8] complex (1), the pentanuclear [Cd3(hmpy)6Co2(μ-CN)6(CN)6] cage complex (2) and the 3D framework [Zn(hmpy)2Zn2(hmpy)2Co2(µ-CN)8(CN)4]n (3). These new cyanide-bridged heteronuclear complexes have been characterised by FT-IR and Raman spectra, together with thermal and elemental analyses. Their structures have been determined by single crystal X-ray diffraction (SC-XRD) and powder X-ray diffraction (PXRD) analyses. In 1, the Cd(II) and Fe(III) centers are arranged alternately at the four corners of a rhombic core, and the cyanide ligands coordinate to the four metal centers of this core in the bridging mode. Adjacent tetranuclear rhombic cores further extend to a decaheteronuclear cluster structure via bridging cyanide ligands. Complex 2 has a pentaheteronuclear cage structure and the neighboring two Co(III) and three Cd(II) centers are bridged by six cyanide ligands. Complex 3 features an unprecedented 3D heterometallic Co(III)-Zn(II) framework based on cyanide ligands.