Different phases of Cu(II)-based complexes with 1,10-phenanthroline impact intermolecular interactions, DNA binding affinities, and spectroscopic, electronic, microbiological and pharmacokinetic properties

• A novel Cu(II)-phenanthroline phase was synthesized, alongside a known phase, to investigate their distinct properties; • Single-crystal X-ray diffraction shows that its structure belongs to the triclinic system and P 1 ¯ -space group; • High capacity to bind DNA has been shown by molecular docking; • Antibacterial activity was shown against Gram positive and Gram-negative strains; • In silico pharmacokinetic properties suggests it as substrate of glycoproteins. Two copper(II) complexes with 1,10-phenanthroline (phen), [Cu 2 (C 12 H 8 N 2 ) 2 (H 2 O)] (NO 3 ) 2 ·(H 2 O) and [Cu(C 12 H 8 N 2 ) 3 ] (NO 3 ) 2 ·(H 2 O) 2 , respectively named as MI and MII phases, were successfully synthesized and their properties investigated. Single-crystal X-ray diffraction (XRD) analysis revealed that both complexes crystallize in the triclinic system with P 1 ¯ -space group, exhibiting distinct structural phases. The MII phase obtained herein has never been reported in the literature, being thus identified as a new phase. Hirshfeld surface analysis highlighted that H⋯O/O⋯H and H⋯H interactions dominate, contributing to 38.9 % and 36.2 % of the total interactions for MI and MII phases, respectively. Functional groups were identified using Fourier-transform infrared (FT-IR) and Raman spectroscopy. Electronic and optical properties were investigated using density functional theory calculations with the CASTEP Package. From molecular docking, both MI and MII phases were found to have a high capacity for binding to the DNA structure; however, with different binding affinities. Antibacterial assays demonstrated significant activity against E. faecalis ATCC 29212, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 strains. The estimation of the in silico pharmacokinetic properties confirmed limited risk of toxicity of the complexes, which can be suggested as glycoproteins’ substrate.