Synthesis, Photophysical, Antimicrobial Activity and <i>In‐silico</i> Study of Homoleptic Dithiocarbamate Complexes [M <sup>II</sup> {k <sup>2</sup> S^S‐S <sub>2</sub> CN(R)CH <sub>2</sub> C <sub>6</sub> H <sub>4</sub> OH} <sub>2</sub> ] (R=2‐picolyl, 3‐picolyl; M=Ni <sup>II</sup> , Cu <sup>II</sup> , Zn <sup>II</sup> )
Heena A. Parmar, Bhaveshkumar B. Makwana, Vinay K. Singh
Abstract
Abstract An array of mononuclear dithiocarbamate complexes [M II { k 2 S^S‐S 2 CN(R)CH 2 C 6 H 4 OH} 2 ] (R=2‐picolyl, M=Ni II 1 , Cu II 2 , Zn II 3 , R=3‐picolyl, M=Ni II 4 , Cu II 5 , Zn II 6 ); incorporating heterocyclic backbone were synthesised from (2‐hydroxybenzyl)(2‐picolyl)amine ( HL 1 ) and (2‐hydroxybenzyl)(3‐picolyl)amine ( HL 2 ) precursors. The formulation of these complexes was examined using various spectroscopic and analytical techniques ( 1 H NMR, 13 C NMR, FTIR, UV‐visible, Fluorescence, TGA/DTA) and further corroborated by DFT level calculation. Notably, precursors HL 1 and HL 2 exhibits maximum emission in the visible nm region ( ca 502 and 408 nm) upon excitation of ultraviolet radiation at ~280 nm with concomitant Stokes shift ca 220 and 128 nm, respectively. The emission properties of these evidently suppressed after complexation with metal ions. Stability of 1 – 6 were determined by thermogravimetric analysis. The magnetic moment along with UV‐visible of 1 – 6 suggests square‐planar environment around Ni II and Cu II and tetrahedral environment around Zn II in 1 – 6 which is in accord with their optimized geometries. Compounds were screened for in‐ vitro antimicrobial activity against E. coli , P. aeruginosa, S. aureus, S. pyogenes, C. albicans, A. niger, A. clavatus by broth dilution method. Molecular docking study was performed to rationalize the results.