Solvent Effect on the Ligand Exchange between Bis(diethyldithiocarbamato)copper(II) and Bis(diethyldiselenocarbamato)copper(II)

EPR and spectrophotometric study on the products of ligand‐exchange taking place on mixing bis(diethyldiselenocarbamato)copper(II), [Cu(Et 2 dsc) 2 ], and bis(diethyldithiocarbamato)copper(II), [Cu(Et 2 dtc) 2 ], solutions is reported. EPR spectra monitored at room temperature for one month period reveal a stable equilibrium among the parents (chromophores CuS 4 and CuSe 4 ) and the obtained mixed‐chelate [Cu(Et 2 dtc)(Et 2 dsc)] complex (chromophore CuS 2 Se 2 ) in heptane, hexane, benzene, toluene, acetone, DMFA, DMSO and dichloromethane. In CCl 4 and CHCl 3 two new additional EPR spectra appear attributed to the mixed‐chelate complexes with the chromophores CuSSe 3 and CuS 3 Se which are not observed with electronic spectroscopy. The intensities of all five EPR spectra decrease with the time. It is assumed that the new mixed‐chelates observed in CCl 4 and CHCl 3 are obtained in a reaction of [Cu(Et 2 dtc)(Et 2 dsc)] or [Cu(Et 2 dtc) 2 ] with the ester of diselenocarbamic acid which is formed in a parallel reaction of [Cu(dsc) 2 ]with CCl 4 or CHCl 3 .