Metal Ions in Biological Systems

Topics in current chemistry

New Cu(II), Co(II), Ni(II) complexes with aroyl-hydrazone based ligand. Synthesis, spectroscopic characterization and in vitro antibacterial evaluation

The role of some thiosemicarbazide derivatives as corrosion inhibitors for C-steel in acidic media

Synthesis, spectroscopic characterization and antimicrobial activity of binuclear metal complexes of a new asymmetrical Schiff base ligand: DNA binding affinity of copper(II) complexes

Physical and spectroscopic studies on novel vanadyl complexes of some substituted thiosemicarbazides.

Mono- and binuclear complexes of malonyl bis(thiosemicarbazide), H4 MBT, with VO2+, Co2+, Ni2+, Cu2+, Cd2+ and Pt4+ have been isolated. The elemental analyses, magnetic moments, spectra [u.v.–vis., i.r., e.s.r. (for Cu2+; VO2+) and mass], thermal and voltammetric measurements [for Co2+ and Ni2+] have been used to characterize the isolated complexes. The ligand behaves as binegative quadridentate with Cu2+, Co2+ and VO2+ ions, binegative pentadentate with Pt4+ and hexadentate, either as trinegative in [Cd2(HMBT)(OC2H5)(C2H5OH)]H2O or mononegative in [Ni2(H3MBT)(OAc)3(C2H5OH)]. The lack of thiol and/or enol hydrogen during the complex formation was confirmed pH-metrically. The pK’s (10.70, 8.50 and 8.15) of H4MBT reveal the removal of CSNH protons in one step and CONH in two steps. Also, the stability constants reveal a higher value for the Cu2+ complex and a lower one for VO2+. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. The kinetic and thermodynamic parameters for some decomposition steps in VO2+and Pt4+ thermograms have been calculated

Spectral, magnetic, electrical and thermal studies on malonyl bis(thiosemicarbazide) complexes

The chelation behavior of some =N(1) and NH(4) thiosemicarbazones towards copper(II) ions has been investigated The isolated complexes are characterized by elemental analysis, magnetic moment, electronic, IR, ESR and ms spectra, and by thermal and voltammetric measurements The substituents on =N(1) and/or NH(4) thiosemicarbazones and the log K values of the ligands play an important role in complex formation The IR spectra showed that the reagents HAT, HAET, HAPT, HApClPT, H2ST and HBT are deprotonated in the complexes and act as mononegative SN donors; H2SET, H2SpClPT, H2HyMBPT and H2HyMBpClPT, as binegative NSO donors while H2SPT is a mononegative NSO donor The ESR spectra of the complexes are quite similar and exhibit axially symmetric g-tensor parameters with g ‖ > g ⊥ > 20023 The loss of thiol and/or hydroxyl hydrogen was confirmed from potentiometric titrations of the ligands and their copper(II) complexes The protonation constants of the ligands as well as the stability constants of their Cu

Spectral, magnetic, thermal and electrochemical studies on new copper(II) thiosemicarbazone complexes

Synthesis and structural investigation of mono- and polynuclear copper complexes of 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide.

4-Ethylthiosemicarbazide and its NH(1) derivatives have been prepared and confirmed by elemental analysis and 1H NMR spectra to produce diverse complexes with Co(II), Ni(II) and Cu(II) ions. The obtained complexes have been investigated based on elemental and thermal analyses, spectral (UV/VIS, ESR, mass) studies and magnetic measurements. The IR data reveal the presence of variable modes of chelation for the investigated ligands. The electronic spectra of the complexes as well as their magnetic moments provide information about geometries. The ESR spectra give evidence for the proposed structure and the bonding for some Cu(II) complexes. Thermal decomposition of some complexes ended with metal or metal oxide as a final product.

I.M. Gabr

Papers

Physical and spectroscopic studies on novel vanadyl complexes of some substituted thiosemicarbazides.

Spectral, magnetic, electrical and thermal studies on malonyl bis(thiosemicarbazide) complexes

Spectral, magnetic, thermal and electrochemical studies on new copper(II) thiosemicarbazone complexes

Synthesis and structural investigation of mono- and polynuclear copper complexes of 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide.

Synthesis and spectroscopic characterization of new mono- and binuclear complexes of some NH(1) thiosemicarbazides