Syntheses and structural studies of cobalt(II), nickel(II), zinc(II) and cadmium(II) selenocyanate complexes with a tetradentate N4-donor ligand

Four new selenocyanate containing mononuclear complexes of the types [M(NCSe)(dbdmp)]ClO4 [M = Co(II), Zn(II)], [Ni(dbdmp)(NCSe)2] and [Cd(dbdmp)(SeCN)2] where dbdmp = N,N-diethyl-N′,N′-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine have been synthesized and characterized by microanalysis, physico-chemical and spectroscopic methods. The crystal structures of the four complexes [Co(NCSe)(dbdmp)]ClO4 (1) [Ni(dbdmp)(NCSe)2] (2), [Zn(NCSe)(dbdmp)]ClO4 (3) and [Cd(dbdmp)(SeCN)2] (4) have been solved by single crystal X-ray diffraction studies and they showed that complexes 1 and 3 have a distorted trigonal bipyramidal geometry, whereas complexes 2 and 4 have a distorted octahedral geometry and the ligand dbdmp shows two different isomers in the complexes 2 and 4. In complex 4, the selenium atom is bonded to the cadmium(II) center, whereas the nitrogen atom of the selenocyanate ion is coordinated to Co(II), Ni(II) and Zn(II) centers in 1–3.

Graphical abstractThe synthesis and structural characterization of four new mononuclear selenocyanide containing complexes [M(NCSe)(dbdmp)]ClO4 [M = Co(II), Zn(II)], [Ni(dbdmp)(NCSe)2] and [Cd(dbdmp)(SeCN)2], where dbdmp = N,N-diethyl-N′,N′-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine, have been discussed. Single crystal X-ray diffraction studies showed [Co(NCSe)(dbdmp)]ClO4 and [Zn(NCSe)(dbdmp)]ClO4 have a distorted trigonal bipyramidal geometry, whereas complexes [Ni(NCSe)2(dbdmp)] and [Cd(dbdmp)(SeCN) have a distorted octahedral geometry.Figure optionsDownload full-size imageDownload as PowerPoint slide