Hemiparetic koneramine NNP ligand comprising strategic hard and soft donors: transition metal complexes, CS2 activation and therapeutic potential

Abstract

A novel koneramine-derived tridentate NNP ligand has been designed and synthesized, and its coordination chemistry explored with hard and soft metal centres, including Zn(II), Pd(II), Ru(II), Cu(I), Cu(II), and Ni(II). The resulting complexes were characterized by spectroscopic, structural, and electrochemical methods, revealing the ligand's electronic flexibility and its ability to stabilize copper in multiple oxidation states (Cu(I)/Cu(II)) via selective donor interactions and adaptable coordination geometries. A ruthenium hydride complex, [Ru(NNP)(H)Cl(CO)], exhibits efficient hydride transfer reactivity and undergoes double carbon disulfide (CS₂) insertion into the Ru–H bond to afford [Ru(NNP)(CS₂H)₂(CO)], highlighting its potential in small-molecule activation. Preliminary biological studies show that syn- and anti-rac-[Ru(NNP)(H)Cl(CO)] display potent antibacterial activity against S. aureus ATCC29213 (MIC = 2 μg mL⁻¹), while anti-rac-[Ru(NNP)(H)Cl(CO)] and [Zn(NNP)Cl₂] exhibit enhanced anticancer efficacy and lower cytotoxicity toward non-cancerous cells compared to cisplatin, highlighting their therapeutic potential.