One-pot crystallization of 1,4-cyclohexanedicarboxylate based two tetranuclear Cu(II) compounds impacts on DNA binding affinities

Two new tetranuclear compounds [Cu4(cis-1,4-chdc)2(2,2'-bpy)4]•4(ClO4) (1) and [Cu4(cis-1,4-chdc)2(2,2'-bpy)4(µ2-OH)2]•2ClO4•2H2O (2) [1,4-H2chdc = 1,4-cyclohexanedicarboxylic acid, 2,2'-bpy = 2,2'-bipyridine] have been prepared by stirring copper(II) perchlorate hexahydrate [Cu(ClO4)2•6H2O] with 2,2'-bpy and sodium-salt of 1,4-H2chdc. The compounds are formed in one-pot crystallization and visibly distinct in colour with dark blue and sky blue appearances respectively for 1 and 2. Both compounds have been characterized by elemental analysis as well as single crystal X-ray diffraction (SCXRD) technique. Interestingly, both the compounds show significant DNA binding affinity with ctDNA and these experimental findings are further corroborated by docking study. However, compound 1 with more cationic charge exhibits better DNA binding affinity compared to 2.