Synthesis, spectroscopic characterization and in vitro studies of new heteroleptic copper (II) complexes derived from 2-hydroxy napthaldehyde Schiff’s bases and N, N donor ligands: Antimicrobial, DNA binding and cytotoxic investigations

• Published in: Inorganica Chimica Acta 2015-07, Vol.433, p.26-34
• Main Authors: Kiran, Tummalapalli, Prasanth, Vuppalapati Giri, Balamurali, M.M., Vasavi, C.S., Munusami, Punnagai, Sathiyanarayanan, Kulathu Iyer, Pathak, Madhvesh
• Format: Article
• Language: English
• Subjects: Antimicrobial and cytotoxicity; Copper (II) complexes; DNA binding; DNA cleavage; Molecular docking studies
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2015.04.033

Eight novel metallacyclic derivatives of copper (II) have been synthesized and structurally characterized as a pent-coordination around central metal. Significant biological applications e.g. DNA binding, DNA cleavage, antimicrobial, molecular docking and cytotoxicity of these complexes were found remarkably well. [Display omitted] •Synthesis of new metallo organic derivatives of copper (II) in ambient conditions.•Characterization of monomeric copper (II) complexes by spectroscopic techniques.•All eight complexes have been tested for DNA binding, observations were encouraging.•An interesting variation in antimicrobial activity has been noticed in these complexes.•Cytotoxic studies only for two complexes have been carried out with fruitful results. A series of eight new copper (II) complexes of types [Cu(HL1)(B)] (4a–4d) and [Cu(HL2)(B)] (4e–4h), where HL1 is N-(2-hydroxy-1-naphthalidene)-2-aminophenol, HL2 is N-(2-hydroxy-1-naphthylidene)-2-mercaptoaniline and B is N, N donor ligands viz bipyridyl (bpy), 1,10-phenanthroline (phen), dipyridoquinoxaline (dpq) and dipyridophenazine (dppz) have been synthesized and characterized by elemental analysis as well as by spectroscopic techniques (IR, UV, ESI mass and EPR spectra). The DNA-binding properties of these copper complexes (4a–4h) have been investigated by electronic absorption, viscosity measurements and docking analyses. The results obtained indicated that the complexes get bonded with DNA via an intercalation binding mode with an intrinsic binding constant, Kb (1.116±0.21 to 7.227±0.21)×104M−1. The antimicrobial activity assays with the Schiff’s bases and their heteroleptic copper (II) complexes of 4a and 4b exhibited profound activity against gram positive bacteria, gram negative bacteria and fungi. Further, complexes 4d and 4h displayed significant cytotoxicity when examined in vitro on a panel of cancerous cell line – human liver cancer cell line – HepG-2 cells (IC50=40.82 and 29.74μg/ml).