Hierarchical self-assembly of self-assembled Pd(II) complexes: Synthesis, structural characterization, crystal packing evaluation and docking studies

Abstract

Binuclear Pd(II) self-assemblies with composition [Pd2(bpy)2(L)2](NO3)4, 1 and [Pd2(phen)2(L)2](NO3)4, 2 were synthesized by equimolar combination of the multi-dentate ligand N, Nʹ-di(pyridin-3-yl)pyridine-2,6-dicarboxamide, L with suitable cis-protected palladium(II) units. Complexes 1 and 2 were characterized by 1H NMR, 13C NMR, COSY, HSQC and ESI-MS. The molecular structure of complexes 1 and 2 were determined by single crystal X-ray diffraction technique. Solid state structure for complex 1 displays a unique three dimensional array of molecules which resembles an “egg tray” through inter molecular π-π- stacking using the strategically located π-surfaces of the cis-protecting units as well as the ligand. Molecular docking study shows excellent interaction of complexes 1 and 2 at the active site of Protein-Arginine-N Methyltransferase 1 with binding energy -9.34 and -9.73 kcal/mol, respectively.