Triply phenoxo bridged Eu( iii ) and Sm( iii ) complexes with 2,6-diformyl-4-methylphenol-di(benzoylhydrazone): structure, spectra and biological study in human cell lines

• Published in: New journal of chemistry 2015-01, Vol.39 (2), p.1101-1114
• Main Authors: Das, Kuheli, Nandi, Soumendra, Mondal, Sudipa, Askun, Tulin, Cantürk, Zerrin, Celikboyun, Pinar, Massera, Chiara, Garribba, Eugenio, Datta, Amitabha, Sinha, Chittaranjan, Akitsu, Takashiro
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/C4NJ01464B

Two dinuclear lanthanide( iii ) complexes, [M 2 (HL) 3 ] (M = Sm( iii ) ( 1 ), Eu( iii ) ( 2 ); H 3 L, 2,6-diformyl-4-methylphenol-di(benzoylhydrazone)) were generated with good yield and characterised systematically. The single crystal X-ray structure determination of [Eu 2 (HL) 3 ] ( 2 ) confirmed the tricapped trigonal prismatic geometry of the N 3 O 6 coordination environment around europium. Indeed, Eu( 1 ) and Eu( 2 ) are bridged by phenolato-O belonging to the p -cresol ring, by deprotonated ‘enol’ groups from the benzoyl hydrazide part and by the imine-N centres. A temperature dependent magnetic study suggested that anti-ferromagnetic coupling occurs between the two Eu( iii ) ions and the magnetic moment was found to vary from 0.48 B.M. at 5 K to 3.03 B.M. at 300 K. Electron paramagnetic resonance spectroscopy confirmed that anti-ferromagnetic coupling occurs between the atoms of Eu( iii ) and Sm( iii ). Both the complexes show emission in the visible range. The ligand, H 3 L and the complexes exhibit anti-mycobacterial activity against M. tuberculosis H37Rv (ATCC 27294) and M. tuberculosis H37Ra (ATCC 25177) strains. The molecular docking of H 3 L with the enoyl acyl carrier protein reductase of M. tuberculosis H37R v (PDB ID: 4U0K) was examined and the best docked pose of H 3 L was shown to have one hydrogen bond with Thr196 (2.03 Å).