Five novel dinuclear copper(II) complexes: Crystal structures, properties, Hirshfeld surface analysis and vitro antitumor activity study

Abstract Five dinuclear copper(II) complexes have been synthesized with three kinds of Schiff bases and Cu(NO 3 ) 2 ·H 2 O in different solvent systems: [Cu 2 (bdhc)(CH 3 OH)(NO 3 )(dmf) 2 ] ( 1 ), [Cu 2 (bdhc)(CH 3 CH 2 OH)(NO 3 )(dmf) 2 ] ( 2 ) [Cu 2 (bchc)(CH 3 CH 2 OH)(NO 3 )(dmf) 2 ] ( 3 ), [Cu 2 (bchc)(CH 3 OH)(NO 3 )(dmf) 2 ] ( 4 ), [Cu 2 (bbhc)(H 2 O)(dmf) 2 ]·NO 3 ·H 2 O ( 5 ) (H 3 bdhc is 1,5-bis(3,5-dibromosalicylidene)-carbohydrazide, H 3 bchc is 1,5-bis(3,5-dichlorosalicylidene)-carbohydrazide, H 3 bbhc is 1,5-bis(5-bromosalicylidene)-carbohydrazide). All the compounds were characterized by IR spectroscopy, Element analysis and X-ray single-crystal diffraction. The anti-proliferative activity of 1 – 5 was evaluated against a panel of human tumor cells while 3 exhibited a high antitumor activity against T-24, A549, SK-OV-3 and MGC-803. A detailed analysis of Hirshfeld surface and 2D fingerprint plot revealed that 1 – 5 were supported mainly by H⋯H, C-H⋯X (X = Cl, Br) and O⋯H intermolecular interactions. Fluorescence properties indicate that all the complexes exist fluorescence concentration self-quenching effect. The magnetic properties of 1 from 2 to 300 K are also discussed.