Synthesis, characterization and anticancer activity of new zinc(II), molybdate(II), palladium(II), silver(I), rhodium(III), ruthenium(II) and platinum(II) complexes of 5,6-diamino-4-hydroxy- 2-mercaptopyrimidine Fatema A. El-Morsy a , Bertrand J. Jean-Claude b , Ian S. Butler c , Shadia A. El-Sayed d , Sahar I. Mostafa a,⇑ a Chemistry Department, Faculty of Science, Mansoura University, Mansoura 35516, Egypt b Royal Victoria Hospital, Department of Medicine, Montreal, QC H3A 1A1, Canada c Department of Chemistry, McGill University, Montreal, QC H3A 2K6, Canada d Chemistry Department, Faculty of Science, Damietta University, Egypt article info Article history: Received 22 April 2014 Received in revised form 7 July 2014 Accepted 10 July 2014 Available online 22 July 2014 Keywords: Mercaptopyrimidine derived ligand Zinc(II) Palladium(II) Platinum(II) MoO 2 2+ Anticancer abstract New complexes of 5,6-diamino-4-hydroxy-2-mercaptopyrimidine (Hdahmp), [Zn(Hdahmp) 2 Cl 2 ], [Zn(bpy)(dahmp)]Cl, [Zn(Hdahmp) 2 ]SO 4 , [Pd(Hdahmp)(dahmp)]Cl, [Pt(dahmp-H)] + n , [M(bpy)(dahmp]Cl, [M(bpy)(Hdahmp]Cl 2 (M(II) = Pd, Pt), [Ru(dahmp) 2 (PPh 3 ) 2 ], [Rh(dahmp) 2 (H 2 O) 2 ]Cl, [Ag 2 (Hdahmp) 2 ], cis- [MoO 2 (dahmp / 3HCl) 2 ] and cis-[MoO 2 (Hdahmp)(DMF)Cl]Cl have been synthesized and characterized on the basis of elemental analyses, IR, NMR ( 1 H, 13 C, 31 P), UV–Vis and ESI-mass spectrometry, thermal and molar conductivity measurements. 5,6-Diamino-4-hydroxy-2-mercaptopyrimidine exhibits five different modes of chelation: (i) a neutral bidentate ligand through the cyclic nitrogen (N-3) and thione sulfur atoms, (ii) a mononegative bidentate ligand through the deprotonated cyclic nitrogen (N-1) and thione sulfur atoms, (iii) a mononegative bidentate ligand through the cyclic nitrogen (N-3) and deprotonated hydroxy centers, (iv) a tetradentate ligand through the cyclic nitrogens (deprotonated N-1, N-3), thione and deprotonated hydroxy oxygen centers, and (v) a mononegative bidentate through the deprotonated cyclic nitrogen (N-3) and ketonic oxygen atoms. The free Hdahmp and several of its complexes have been tested against the human serous ovarian cancer (OV-90) and human ovarian cancer (OVCAR-8) cell lines. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction The pyrimidine ring system occurs widely in living organisms. Purines, uric acid, alkoxan, barbituric acid, and antimalarial, anti- bacterial and anticancer drugs all contain pyrimidine rings [1–3]. Pyrimidine itself is not found in nature but compounds containing pyrimidine ring systems are well known and are biological active. Pyrimidine is an important component of nucleic acids and is used as a building block in pharmaceuticals for the synthesis of antiviral, anticancer, antibacterial and antifungal agents [4–6]. Similarly, 4- hydroxy-2-mercaptopyrimidine (thiouracil) derivatives are poten- tial therapeutics, i.e., as antiviral and anticancer agents [7], [8]. When thio, oxo or amino groups are present at the 2-, 4- or 6-posi- tions in substituted pyrimidines, tautomers exist forming mer- capto-, hydroxy and imino functions, respectively [9]. In addition, pyrimidine derivatives in transition metal complexes are of consid- erable interest because of their well-known anti-cancer, anti- metastase and anti-microbial activity [7,8]. Among these com- plexes, palladium(II) thiopyrimidine compounds are of particular importance because of the significant Pd(II)–S interactions present in biological systems [10]. Over the past few years, our laboratory has been actively involved in the synthesis of various transition metal complexes of 2-thiopyrimidine derivatives [11–14]. Some of these complexes have been evaluated as anticancer agents against Ehrlich ascites tumor cells (EACs) [13] and human breast cancer MDA-MB231 cell line [14]. As part of our continued interest in synthesizing new com- plexes with expected pharmaceutical activity, we report here the synthesis of complexes of 5,6-diamino-4-hydroxy-2-mercaptopy- rimidine (Hdahmp) with Zn(II), MoO 2 2+ , Ru(II), Pd(II), Ag(I), Rh(III) and Pt(II). The structures of the complexes are discussed in terms of their elemental analyses, spectral (IR, UV–Vis., NMR, mass), thermal and molar conductivity measurements. In addition, the http://dx.doi.org/10.1016/j.ica.2014.07.031 0020-1693/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +20 0100 8502625; fax: +20 050 2246781. E-mail addresses: sihmostafa@gmail.com, ian.butler@mcgill.ca (S.I. Mostafa). Inorganica Chimica Acta 423 (2014) 144–155 Contents lists available at ScienceDirect Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica