Synthesis, structural and spectral characterization of Zn(II) complexes, derived from thiourea and thiosemicarbazide S.I. Orysyk a,⇑ , V.V. Bon a , O.O. Obolentseva a , Yu. L. Zborovskii b , V.V. Orysyk b , V.I. Pekhnyo a , V.I. Staninets b , V.M. Vovk b a V.I. Vernadskii Institute of General and Inorganic Chemistry NAS of Ukraine, Palladin Av. 32/34, 03680 Kyiv, Ukraine b Institute of Organic Chemistry NAS of Ukraine, Murmanska Str. 5, 02660 Kyiv, Ukraine article info Article history: Received 9 April 2011 Received in revised form 18 August 2011 Accepted 6 October 2011 Available online 20 October 2011 Keywords: Thiourea derivatives Carbothioamide Zn(II) complexes NMR spectroscopy X-ray diffraction study abstract Novel mono- and binuclear complexes of Zn(II) with thiourea derivatives (H 2 L) (N-2-propenyl-N 0 -2- pyridinylthiourea) and thiosemicarbazide, H 3 L (2-[(2-hydroxyphenyl)methylene]hydrazine-N-(2-prope- nyl)carbothioamide, (2-[(2-hydroxyphenyl)methylene]hydrazine-N-phenylcarbothioamide) have been synthesized. The possibility of mono- or tridentate coordination to the central metal ion of these ligands both in neutral and in monodeprotonated thionic tautomeric form with the stoichiometric ratios Zn:L = 1:1 and 1:2 has been shown. The synthesized complexes Zn(CH 3 COO) 2 (H 2 L) 2 (I), Zn 2 (CH 3 COO) 2 (H 2 L) 2 Zn 2 (CH 3 COO)(H 2 O)(H 2 L) 2 (II), Zn(H 2 L) 2 (III), Zn 2 (CH 3 COO) 2 (H 2 L) 2 (IV) have been studied by IR, UV–Vis, 1 H, 13 C NMR spectroscopy and single crystal X-ray diffraction (I, II, IV). It has been established that in compound (I) the central Zn atom forms a strongly distorted tetrahedral ZnS 2 O 2 coordination, while in (II) and (IV) it forms a square-pyramidal ZnSNO 3 environment. In the case of complex (II) the asymmetric unit contains two molecules of binuclear complex compounds, which are slightly differ by coordination in vertex direction of Zn polyhedron. The square-pyramidal geometry of Zn(II) ions from the first molecule completed by two acetate anions, which is similar to compound (IV). In the second molecule, the Zn(II) coor- dination polyhedrons are completed by one acetate anion and one water molecule. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction Zinc is a biologically essential element [1]. Zn(II) ions as a cofac- tor are part of over 300 enzymes (carbonic anhydrases, zinc pro- teinases, histone deacetylases, alkaline phosphatases, alcohol dehydrogenases, aminopeptidases, etc.), which involved in meta- bolic processes of living organisms: viruses, bacteria, plants and animals [1–8]. Many of the above mentioned enzymes can also participate in processes giving rise to pathological states. For example, zinc-containing proteinases, which are produced by viruses, split the host’s protein into small fragments, from which new copies of viruses are then created [9,10]. Zinc proteinases are included in the life cycle of different kind of bacteria sometimes also pathogenic ones [8]. The activity of zinc proteinases and his- tone deacetylases increases greatly when cancer diseases or a number of other diseases arise [3,5–7,11–14]. Therefore, the efforts of many laboratories are directed at search for effective inhibitors of zinc-containing enzymes, which are of interest as potential pharmaceuticals. The compounds that are able to bind into stable complexes Zn(II) ions, located in the active site of enzymes can serve as such inhibitors [3–7,11,14,15]. It is logical to assume that the functional derivatives of thiocarbamic acid, in particular thio- urea and thiosemicarbazone, which are known in literature as sen- sitive reagents for the extraction–photometric determination of Zn(II) [16], will possess such an activity. Moreover, complexes of thiosemicarbazones with a number of transition metal ions show a high bioactivity and are of interest as potential anticancer, anti- viral, antibacterial and anti-inflammatory drugs [17–21]. In the synthetic aspect, thiourea and thiosemicarbazide deriva- tives are of interest as effective complexing agents for transition metal ions. In particular, it has been shown that N-2-propenyl- N 0 -2-pyridinylthiourea forms stable complexes with Bi(III) ions [22], while 2-[(2-hydroxyphenyl)methylene]hydrazincarbothioa- mide derivatives form ones with Zn(II) ions [23–25]. Thiourea and its derivatives are part of the complexes as poly- dentate ligands since their molecule contains several nucleophilic electron-donor centers, the geometry of whose arrangement and the electronic configuration of complexing metal determine the possibility of forming various structure complexes [26–30]. Like other ambidentate ligand systems, they are characterized by com- petitive coordination; which defines the scientific interest in study 0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2011.10.027 ⇑ Corresponding author. E-mail address: orysyk@ionc.kiev.ua (S.I. Orysyk). Inorganica Chimica Acta 382 (2012) 127–138 Contents lists available at SciVerse ScienceDirect Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica