Ground state charge transfer complex formation of some metalloporphyrins with aromatic solvents: Further theoretical and experimental investigations.

In our earlier work (Chem. Phys. Letts. 592 (2014) 149-154), a new broad band was observed in the near infrared region (700-900nm) of the steady state absorption spectra of some metalloporphyrins (zinc tetraphenylporphyrin, zinc octaethylporphyrin and magnesium octaethylporphyrin) in aromatic solvents (chlorobenzene, 1,2-dichlorobenzene, benzonitrile, benzene and toluene) at high concentrations (~10-4molL-1). The band was ascribed to be due to ground state charge transfer complexation between solute and solvent molecules. In the present work, density functional theory calculations are carried out to study the possibility of such ground state charge transfer complex formation between zinc tetraphenylporphyrin and four aromatic solvents viz., benzene, toluene, chlorobenzene and benzonitrile with 1:1 and 2:1 solvent-solute stoichiometries. Also, we determined the association constants for the ground state charge transfer complex formation of zinc tetraphenylporphyrin and zinc octaethylporphyrin with two aromatic solvents (benzene and benzonitrile) by Benesi-Hildebrand method.

Electronic and magnetic properties of pristine and transition metal doped ZnTe nanowires.

We have carried out density functional theory based calculations for understanding the structural, electronic and magnetic properties of pristine and transition metal (TM) doped ZnTe nanowires. Pristine ZnTe nanowires (NWs) turn out to be semiconducting in nature, with the band gap varying with the diameter of the NWs. In Mn-doped ZnTe NWs, the Mn atoms retain a magnetic moment of 5 µB each and couple anti-ferromagnetically. A half metallic ferromagnetic state, although energetically not favorable, is observed arising from a strong hybridization between the d-states of Mn atoms and p-states of Te atoms. Further studies of V- and Sc-doped ZnTe NWs reveal the systems to be anti-ferromagnetic.