Diethylaminophenyl-based Schiff base Cu(ii) and V(iv) complexes: Experimental and theoretical studies and cytotoxicity assays

ECHEVERRÍA, GUSTAVO A.; LEÓN, IGNACIO E.; ROCHA, MARIANA; PIRO, OSCAR E.; FRONTERA, ANTONIO; RUIZ, MARÍA C.; DI VIRGILIO, ANA L.; GIL, DIEGO M.

NEW JOURNAL OF CHEMISTRY

Royal Society of Chemistry

Lugar: Londres; Año: 2019 vol. 43 p. 18832 - 18842

1144-0546

An N,N,O,O donor Schiff base blocking ligand [H2L = 6,60-((1E,10E)-(ethane-1,2-diylbis(azaneylylidene))-bis(methaneylylidene))bis(3-(diethylamino)phenol), 1] has been used to synthesize mononuclear [CuL].H2O (2) and [VO(L)] (3) complexes. The ligand and complexes have been characterized by elemental, spectral (FTIR and UV-vis) and thermogravimetric analysis. The molecular structures of 1 and 2 have been confirmed by single crystal X-ray diffraction studies. The crystal structure of the ligand (1) indicates that the molecule is sited on a crystallographic inversion centre and the planar conformation of the salicylideneimine moiety is favored by two intramolecular O?H...N1 hydrogen bonds forming S(6) ring motifs. The copper(II) center in complex 2 is coordinated in a square planar fashion. The presence of an extended pi-system in the complex (two chelate rings and two phenyl rings) facilitates the formation of chelate ring (CR)...pi non-covalent interactions. DFT calculations have been performed to explore the energetic features of unconventional CR...pi and hydrogen bonding interactions that are observed and described in the solid state of 2. Moreover, we have studied how the energy of the CR...pi interaction isinfluenced by the substituent of the phenyl ring. In addition, the cytotoxic effect of the compounds has been tested against MG-63 (human osteosarcoma), HT-29 (human colorectal) and MCF7 (breast) cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.