Structural and Biological Properties of a Silver and Cobalt Complexes of Sulfamethazine in Presence of Secondary Ligand: An Experimental and Computational Approach

Abstract

Silver and cobalt complexes of SMZ ligand [SMZ = 4-amino-N-(4, 6-dimethyl-2 pyrimidinyl) benzenesulfonamide] have been synthesized and characterized by elemental and FT-IR spectroscopy analysis. Due to the magnetic behaviour of the cobalt complex, it was characterized by EPR and magnetic susceptibility analysis. Single crystal X-ray diffraction study reveals the [Ag2(C12H14N4O2S)2(C6H7N)2], complex-1 crystallizes in orthorhombic space group Pbca, while [{Co(C12H13N4O2S)2(C5H5N)2}.(C5H5N)], complex-2 crystallizes in monoclinic space group C2/c. X-ray diffraction analysis revealed that silver in complex-1 is four-coordinate exhibiting distorted tetrahedral geometry, while cobalt in complex-2 is coordinated to six nitrogens leading to distorted octahedral geometry. The molecular structures of the complexes are stabilized by π…π and C–H…π intermolecular interactions. Furthermore, the computational studies such as frontier molecular orbital (FMO), natural bond orbital (NBO) and Mulliken population analysis (MPA) have been measured using DFT/B3LYP method in gaseous phase of the complexes. The visualized and correlated in a novel way through qualitative investigation using Hirshfeld surface and 3D energy frameworks analysis have been performed of the complexes. Additionally, The MIC data against a panel of gram positive and gram negative organisms suggest that both the complexes possess enhanced inhibitory activities than that of free SMZ ligand. Molecular docking investigation specifies that the binding affinity of the complexes with 1BNA is higher than that of free SMZ ligand.

Keywords: Crystallographic studies of complex-1 and complex-2, DFT studies, Hirshfeld surface analysis, MIC activity