Cyano-bridged bimetallic complexes based on nitroprusside [Fe(CN)5(NO)]2− and [Cu(TAAB-macrocycle)]2+: Synthesis, structure and thermal stability

Two new cyano-bridged bimetallic complexes, [Cu(TAAB)Fe(CN)5(NO)]·2H2O (1) and [Mn(bpy)2(H2O)Fe(CN)5(NO)]·H2O (2) (where TAAB = tetrabenzo[b,f,j,n][1,5,9,l3]tetraaza-cyclohexadecine and bpy = 2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR spectra and TG-DSC analyses. Single crystal X-ray structure analyses revealed that the complex 1 has a cyano-bridged binuclear structure in which Cu(II) center is coordinated by tetraazacyclic TAAB ligand to form an intriguing saddle-shaped structure, and Fe(II) center is in an octahedral coordination environment with nitrosyl group trans to the cyano-bridge. In complex 2, Mn(II) center is cis six-coordinated and linked to nitroprusside though a bridging cyanide group to form a binuclear structure, while the nitrosyl group is cis to the cyano-bridge. The thermal stabilities of both complexes were investigated, which shows the nitrosyl and cyanide groups of nitroprusside released by two-steps in the temperature range of 200–380 °C.