SYMMETRICAL SYNTHESIS AND CHARACTERIZATION OF FIVE-COORDINATE In(III) PORPHYRINS WITH SALICYLIC ACID DERIVATIVES

Abstract

Investigations of the In(III)porphyrin complexes with substituted salicylates(X) as axial ligands have been carried out using electronic and biological studies. Electronic spectra of the complexes are accompanied by shifting of wavelength towards hypsochromic/blue-shift or bathochromic/red-shift along with 'ƒ' values decided by the nature of the functional groups attached to the salicylate ligand. IR frequencies appear at 550cm-1–400cm−1 for In–N(Por) and at 650cm−1–700cm−1 for In–OSA. 1HNMR spectra reveal the merging of the salicylate ring with that of the protons of the macrocyclic ring. The 13CNMR studies confirm the resonance of the meso-carbon tetraphenyl porphyrin ring between 130ppm to 160ppm and the salicylate ring carbons in the region of 110ppm to 165ppm. Thermal analysis confirms the presence of indium nitride (In-N) in an argon atmosphere from 0oC to 900oC. Cyclic voltammetry(CV) revealed the reduced or oxidized properties of these complexes lead to the generation of π-anion or cation radicals by two one-electron transfer reactions. In(III)porphyrin complexes with substituted salicylates were also screened for in-vitro antifungal activity(%inhibition) against the microbe "Acremonium fusidoides spp." using the PDA method, which shows that the percentage inhibition is inverse to the diameter of the colony. The freeradical scavenging or antiradical activity (%RSA) by the DPPH method reveals that these complexes were absorbance and concentration-dependent.