Synthesis, crystal structure, solid state electronic spectra and thermal study of three cobalt(II)-selenocyanate complexes: In situ room temperature transformation of 4,4′-dipyridyldisulfide to 4,4′-dipyridylsulfide

Three new supramolecular networks of cobalt(II), [Co(phen)2(SeCN)2] (1), [Co(bpe)2(SeCN)2]n (2), and {[Co(bps)2(SeCN)2] H2O}n (3) [phen = 1,10-phenanthroline; bpe = 1,2-bis(4-pyridyl)ethane; bps = 4,4- bipyridylsulfide] have been synthesized and characterized by X-ray single crystal structure determination, solid state electronic spectroscopy and thermogravimetric analysis. Complex 1 is a neutral discrete cobalt(II) complex with cis located selenocyanate anions and forms 2D supramolecular layers through p p interactions. Complexes 2 and 3 have a comparable structure based on metal center bridged by two bpe or bps ligands trough pyridinyl N-donor to give rise to a linear chain. The selenocyanate anions (SeCN ) bind the metal centers through nitrogen and occupy trans axial positions of the octahedral metal coordination environment. These pendant pseudohalides located on both sides of the 1D polymeric chain help to reinforce the packing through weak interactions. Solid state electronic spectra of all the complexes corroborate the presence of octahedral high spin cobalt(II) centers in all complexes.