Syntheses, characterization and antimicrobial activity of the first complexes of Zn(II), Cd(II) and Co(II) with N-benzyloxycarbonylglycine X-ray crystal structure of the polymeric Cd(II) complex Djenana U. Miodragovic ´ a, * , Dragana M. Mitic ´ b , Zoran M. Miodragovic ´ a , Goran A. Bogdanovic ´ c ,Z ˇ eljko J. Vitnik a , Maja D. Vitorovic ´ a , Milanka - D. Radulovic ´ d , Branislav J. Nastasijevic ´ a , Ivan O. Juranic ´ a , Katarina K. And - elkovic ´ a a Faculty of Chemistry, University of Belgrade, P.O. Box 158, Studentski trg 12-16, 11000 Belgrade, Serbia b Faculty of Stomatology, University of Belgrade, Dr. Subotic ´a 8, 11000 Belgrade, Serbia c Vinc ˇa institute of Nuclear Sciences, Laboratory of Theoretical Physics and Condensed Matter Physics, 11000 Belgrade, P.O. Box 522, Serbia d Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Studentski trg 14, 11000 Belgrade, Serbia Received 14 March 2007; received in revised form 8 June 2007; accepted 17 June 2007 Available online 6 July 2007 Abstract For the first time, complexes of Zn(II), Cd(II) and Co(II) (1–3) with N-benzyloxycarbonylglycine have been synthesized and charac- terized. The complexes adopt tetrahedral, pentagonal-bipyramidal and octahedral geometry, respectively. The structure of the polymeric cadmium complex was resolved by single crystal X-ray analysis. The cadmium ion has a distorted pentagonal-bipyramidal coordination formed by two water molecules and two N-benzyloxycarbonylglycinato ligands (N-Boc) coordinated in different fashions, one as biden- tate and the second connecting three cadmium atoms. In a rather complicated 2D supramolecular structure, the phenyl rings interact mutually exclusively by the CHÁÁÁp interactions. Investigation of the antimicrobial activity of the obtained complexes and N-benzyloxycarbonylglycine revealed that the ligand does not inhibit the growth of Candida albicans, whereas the newly synthesized complexes suppress the growth of this human fungal pathogen. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Zinc(II), Cadmium(II) and Cobalt(II) complexes; N-Boc-glycine; X-ray; DFT; Microbiological assay 1. Introduction Metal complexes with aromatic amino acids have proved to be simple model systems for studying weak, non-covalent p-interactions in which the aromatic rings participate [1–6]. It was shown that these interactions are very important for many biological molecules [7–10]. In our previous articles, the metal complexes containing aromatic amino acids were described [11–15]. As a continuation, in this study, new metal complexes having N-benzyloxycarbonyl protected amino acids as ligands were examined. The presence of a phenyl ring, as a part of a group attached to the primary amino group of an amino acid enabled investigations on non-cova- lent p-interactions to be continued. It is interesting to note that the N-benzyloxycarbonyl-protected amino acids and their derivatives were reported as anti-convulsant, anti- inflammatory and anti-neoplastic agents [16–21]. The inves- tigated ligand, N-benzyloxycarbonylglycine (N-Boc-glyH), having optimal distribution properties for the penetration of the blood–brain barrier, exhibits better anti-convulsant activity than glycine itself [16–18,21]. 0020-1693/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2007.06.041 * Corresponding author. Tel.: +381 11 3336743; fax: +381 11 184330. E-mail address: dmiodrag@chem.bg.ac.yu (D.U. Miodragovic ´). www.elsevier.com/locate/ica Available online at www.sciencedirect.com Inorganica Chimica Acta 361 (2008) 86–94