Ligand influence on the electrochemical behavior of some copper(II) thiosemicarbazone complexes

Abstract

The redox properties of the title mono-and binuclear copper(II) chelates have been investigated by cyclic voltammetry in DMF at a working platinum electrode. The cathodic reduction and anodic oxidation of the investigated chelates produced the corresponding electrochemical Cu I and Cu III species stable only in the voltammetric time scale, The effects of substituents on E 1/2 , redox properties and stability towards oxidation of the complexes were related to the electron-withdrawing or releasing ability of the substituents on the C@N 1 [H, CH 3 or C 6 H 5 ] and/or N 4 H [H, C 2 H 5 , C 6 H 5 or pClC 6 H 4 ] groups, The electron attracting substituents stabilize the Cu(II) complexes while electron-donating groups favor oxidation to Cu(III). Changes in the E 1/2 for the complexes due to remote substituent effects could be related to changes in basicity of N 4 H.Thus, variation in N 4 1-J has more influence on E 1/2 than changes in C@N 1 . The correlation between E 1/2 of the complexes and pK a of the ligands has been attributed to the spherical potential generated by the electron density of the donor atoms at the antibonding d orbitals.

Synthesis, characterization, and DNA interaction of mononuclear copper(II) and zinc(II) complexes having a hard–soft NS donor ligand

“…Coordination chemistry of ligands containing both nitrogen and sulfur as potential donors is of interest, with the most widely studied the thiosemicarbazones [1][2][3][4][5]. Complexes of this type may have biological properties including antitumor [6], antimicrobial [7] properties as well as physicochemical effects [8].…”

Application of N,N’‐Bis(acetylacetonato)propylenediimine Copper(II) Complex as Mediator for Glucose Biosensor

“…Electrochemical behavior of Cu(acac 2 pn) were determined by cyclic voltammetry in DMSO/PBS pH 6.6 solution. From the obtained voltammogram (Figure ) the peak at 0.0 V can be attributed to the copper oxidation and corresponding copper reduction peaks (−0.175 and −0.25 V) which were more pronounced after the addition of copper‐acetate …”

“…From the obtained voltammogram ( Figure 4) the peak at 0.0 V can be attributed to the copper oxidation and corresponding copper reduction peaks (À 0.175 and À 0.25 V) which were more pronounced after the addition of copper-acetate. [28,34] In mediated electron transfer (MET), electrons transfer from enzyme active site to the electrode surface by mediator who acts as an electron relay. [35] Figure 5 shows cyclic voltammograms of solutions with and without glucose.…”

Synthesis and characterization of a new N2S2 Schiff base ligand and its complexes with nickel(II), copper(II) and cadmium(II) including the kinetics of complex formation

“…Furthermore, thiosemicarbazones have been a subject of interest in recent decades due to their variable applications in industry and analytical chemistry [10,11]. The introduction of transition metal ions into molecules containing a chromophore, which is based on the thiosemicabazones moiety, has resulted in increasing the light fastness [12]. In this paper, we report the synthesis and characterization of phthaldihyde-bis(4-methyl-3-thiosemicarbazone) (PHMTSC) (Scheme 1).…”