Ag(I) symmetrical N,N’-diarylformamidine dithiocarbamate PPh3 complexes: Synthesis, Structural characterization, quantum chemical calculations and in vitro biological studies

Abstract Three heteroleptic silver(I) dithiocarbamate triphenylphosphine complexes were developed in which triphenylphosphine was introduced as a bulky co-ligand and tested as antioxidant activity against the free radical of DPPH. All three complexes showed good antioxidant activity against the free radical of DPPH with compounds 1 and 2 having a better antioxidant activity when compared to ascorbic acid. All the complexes were found to be more active than ciprofloxacin against Gram (+) bacteria while they showed good to moderate activity against Gram (-) bacterial except S. typhimurium. The crystal structures of 2 and 3 were determined by single crystal X-Ray diffraction and confirmed distorted tetrahedral geometry around the Ag(I) center with coordination via two sulfur atoms of the dithiocarbamate ligand and two phosphorus atoms from the two triphenylphosphine ligands replacing the NO3- anion from the silver nitrate salt . The structures of the metal complexes were geometrically optimized, and the quantum chemical parameters were calculated using the density functional theory (DFT) at B3LYP/Lanl2dz basis set. Quantum chemical descriptors based on DFT calculations predicted the stability as well as reactivity of the complexes and there was a clear correlation with the biological activities.