Spectroscopic studies and biological activity of some transition metal complexes of unusual Schiff base Ahmad K. Abu Al-Nasr, Ramadan M. Ramadan ⇑ Applied Chemistry Department, Faculty of Applied Science, Taibah University, Almadinah Almunawrah, Saudi Arabia highlights " Synthesis and analysis of unusual Schiff base from a macrocycle Schiff base (L). " Synthesis and spectroscopic of some transition metal complexes derived from L. " Crystal structure of L was determined through X-ray single crystal analysis. " Biological activity of L and complexes against bacteria and fungus were screened. " Cytotoxicity of [Pt II L(Cl) 2 ] complex was checked as an antitumor agent. graphical abstract Unusual Schiff base ligand, 4-ethanimidoyl-6-[(1E)-N-(2-hydroxy-4-methylphenyl)ethanimidoyl]ben- zene-1,3-diol, L, was synthesized via catalytic process. Some transition metal derivatives were also synthesized from the corresponding metal species with L. The biological activities of L and metal complexes were screened. article info Article history: Received 18 June 2012 Received in revised form 19 November 2012 Accepted 5 December 2012 Available online 27 December 2012 Keywords: Schiff bases Complexes Spectra Biological activity Cytotoxicity abstract Unusual Schiff base ligand, 4-ethanimidoyl-6-[(1E)-N-(2-hydroxy-4-methylphenyl)ethanimidoyl] benzene-1,3-diol, L, was synthesized via catalytic process involving the interaction of some metal ions with a macrocyclic Schiff base (MSB). The transition metal derivatives [ML(H 2 O) 4 ](NO 3 ) 3 , M = Cr(III) and Fe(III), [NiL(H 2 O) 4 ](NO 3 ) 2 , [ML(H 2 O) 2 ](NO 3 ) 2 , M = Zn(II) and Cd(II), [Cl 2 Pd(l-Cl) 2 PdL], [PtL(Cl) 2 ] and [PtL(Cl) 4 ] were also synthesized from the corresponding metal species with L. The Schiff bases and com- plexes were characterized by elemental analysis, mass spectrometry, IR and 1 H NMR spectroscopy. The crystal structure of L was determined by X-ray analysis. The spectroscopic studies revealed a variety of structure arrangements for the complexes. The biological activities of L and metal complexes against the Escherchia coli as Gram-negative bacteria and Staphylococcus aureus as Gram-positive bacteria, and the two fungus Aspergillus flavus and Candida albicans were screened. The cytotoxicity of [PtL(Cl) 2 ] com- plex, a cis-platin analogous, was checked as an antitumor agent on two breast cancer cell lines (MCF7 and T47D) and human liver carcinoma cell line (HepG2). Ó 2012 Elsevier B.V. All rights reserved. 1386-1425/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.saa.2012.12.008 ⇑ Corresponding author. Address: Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt. Tel.: +20 966556404953; fax: +20 96648401743. E-mail address: r_m_ramadan@yahoo.com (R.M. Ramadan). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 105 (2013) 14–19 Contents lists available at SciVerse ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa