Syntheses, crystal structures, spectroscopic and thermal properties of 3D heteronuclear coordination polymers with 4-ethylpyridine and cyanide ligands

Three new hexacyanometallate(III) complexes, namely {[Cd 3 (4epy) 12 Cr 2 (µ-CN) 6 (CN) 6 ]∙4H 2 O} n ( 1 ), {[Cd 3 (4epy) 12 Fe 2 (µ-CN) 6 (CN) 6 ]∙4H 2 O} n ( 2 ) and {[Cd 3 (4epy) 12 Co 2 (µ-CN) 6 (CN) 6 ]∙4H 2 O} n ( 3 ), were synthesized by using 4 - ethylpyridine (4epy) ligand and characterized by spectral (FT - IR and Raman), crystallographic (SC-XRD and PXRD), thermal and elemental analyses techniques. Single crystal studies have shown that heterometallic complexes 1–3 form 3D polymers. Each M ion [M = Cr(III) in 1, Fe(III) in 2 and Co(III) in 3 ] is coordinated by six carbon atoms from cyanide ligands and adjacent metal ions are bridged by cyanide ligands to generate [Cd 6 M 6 (CN) 12 ] clusters. Each Cd(II) ion is coordinated by four nitrogen atoms from 4epy ligands and two nitrogen atoms from cyanide ligands to distorted octahedral coordination geometry. In addition, thermal (TG/DTA) properties of the complexes were investigated. Powder X-ray diffraction (PXRD) patterns of the complexes were recorded to control the phase purities.