Coordination behavior of succinylsulfathiazole – Crystal structure of [Cu(SST).(Pyridine)3.H2O]n, DNA interaction and cytotoxic studies

Abstract

Mononuclear copper complex of succinylsulfathiazole has been synthesized and characterized using relevant spectroscopic and X-ray diffraction techniques. EPR data and X-ray structural analysis confirmed that Cu(II) ion exhibits an intermediate geometry between trigonal and square bipyramid. Succinylsulfathiazole (SST) ligand behaves as a head-to-tail bridging moiety linking two metal (Cu) cations via carbonyl oxygen and thiazolate nitrogen atom, resulting one dimensional polymeric chain running along [010] direction. In the mononuclear copper complex formulated as [Cu(SST).(Pyridine)3.H2O]n, three nitrogen atoms of three secondary ligand pyridines coordinated to copper at the equatorial plane, the fourth coordination of distorted pentadentate copper is due to thiazolate nitrogen (N3) occupying the apical position and carbonyl oxygen (O1) of SST ligand at -x + 1/2, y-1/2, -z-1/2 remaining at fifth coordination site completes the coordination sphere of copper. The inversely related Cu-SST molecular complexes are held together by pair of NH…O dimer forming R22(14) graph set motif which are further connected by water oxygen (O6) via OH…O interactions. Quantitative contributions of intermolecular interactions are worked out using Hirshfeld surface (HS) and 2D fingerprint plots. Lipophilicity index (Log P), correlates well with the% contribution of CH…π interaction. To evaluate the binding capabilities and binding mode of molecular complex with CT-DNA, absorption study and viscosity measurement are carried out, confirming the intercalation mode of binding which is further supported by molecular docking studies. In vitro cytotoxicity screening of the complex have been performed on zoological species Artemia cyst.