Novel insight of indium(III)complex of N, N´-bis(salicylidene)ethylenediamine as chemo-sensor for selective recognition of HSO4− and hemolytic toxicity (Red Blood Cells) studies: Experimental and theoretical studies

Indium(III) complex of N, N´-bis(salicylidene)ethylenediamine prepared was characterized, and employed as chemo-sensor for the recognition of HSO4− after studying the following ions (F−, Cl−, Br−, I−, CH3COO−, PO43-, SCN−, PF6−, HSO4−). The results show that the complex selectively detects HSO4− without interference from the other anions except acetate. The stoichiometry of the interaction between the complex and HSO4− was found to be 1:1. Interestingly, the complex was employed in hemolysis for Red Blood Cells, showing that the complex involves strongly in hemolysis of blood cells evidenced by optical microscopy and Atomic Force Microscopy (AFM). The cell walls were severely damaged by the complex through its interaction with carboxylic group of hemoglobin. However, in the presence HSO4−, the complex was unable to involve the hemolysis because of the binding of HSO4− with the complex. This observation is consistent with the anion interference study where acetate ion interferes in the detection of HSO4−. The intensity of fluorescence of the complex was quenched with the increasing concentration of HSO4−; in the molecular orbital analysis, the HOMO energy level of the complex was used to explain how the excited sate of [InL1(NO3)(HSO4)]− plays a significant role in enhancing or quenching of fluorescence intensity through the Photo Electron Transfer (PET). An increasing energy level of [InL1(NO3)(HSO4)]− quenches the florescence intensity of [InL1(H2O)(NO3)]−.