Spectroscopic studies of metal chelate complexes as lewis acids and/or bases

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

“…On the other hand donor and acceptor properties of copper(II) complexes with respect to their interactions with Lewis base or acid strongly dependends on copper chromophore giving the following order of decreasing acceptor and increasing donor properties [38] (2): CuO 4 > CuO 2 N 2 > CuN 4 > CuN 2 S 2 > CuS 4 > CuS 2 Se 2 > CuSe 4 (2) due to increasing covalent character of the σ metal-equatorial ligand bonds. The explanation is based on the fact that in the same order the remaining positive charge (or acceptor properties) on copper(II) decreases [38]. On the other hand, independently of the strong covalent bonds the partial negative charge remaining on the donor atoms of the chromophore provides their interaction with acceptor centers of other molecules.…”

Solvent effect on the ligand exchange between bis(diethyldithiocarbamato)copper(II) and bis(diethyldiselenocarbamato)copper(II)

“…Therefore, the appearance of these complexes can be attributed to specific donor-acceptor interaction taking place between the solvent molecules and the reagents. The assumption is based on the fact that the chromophores of the studied complexes are characterized with prevailing donor properties [13] and on the other hand, the acceptor properties of the studied chloromethanes increase in the order CH 2 Cl 2 < CHCl 3 < CCl 4 [14,15]. Thus, our explanation of the formation of mixed-ligand complexes ML-2 and ML-3 is based 1 From structural point of view the signal of the mixed-ligand Cu(dtc)(dsc) complex should be characterized by four copper hf lines, part of which (ca.…”