Abstract
Mononuclear complexes of 3-methylpyrazole with general formulas (3-Mepz)
4
CuCl
2
(1), (3-Mepz)
4
CoCl
2
(2), (3-Mepz)
2
PdCl
2
(3), and (3-Mepz)
2
ZnCl
2
(4) were prepared by reaction of the corresponding MCl
2
salt (M = Cu, Co, Pd, and Zn) with 3-methylpyrazole in appropriate amounts using acetonitrile as solvent at ambient temperature. The X-ray crystal structure determination reveals that 1 and 2 possess octahedral geometry, while 3 and 4 are square planar and tetrahedral, respectively. All the synthesized compounds have the MCl
2
fragment, thus making the synthesized compounds attractive synthons for further transformation. The cyclic voltammograms of the synthesized complexes were obtained and the voltammetric signatures of 1, 2, and 4 showed a single irreversible pH-dependent cathodic peak, while 3 has two reversible cathodic peaks. Involvement of protons accompanying the electron transfer processes was ascertained from differential pulse voltammetric results, indicating peak potential shift as a function of pH.
Complexes of M(II) with 3-methylpyrazole as ligand were prepared at ambient temperature using MCl
2
metal salts (M = Cu, Co, Pd, and Zn). Reactions led to the formation of octahedral (Cu, Co), square-planar (Pd), and tetrahedral (Zn) mononuclear complexes. All reactions were straightforward and no appreciable amount of side products was detected. X-ray structures were determined for all the complexes. The cyclic voltammetric investigations indicate the involvement of proton during electron transfer reactions of these complexes.