Journal of Molecular Structure 1247 (2022) 131291 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstr New divalent metal ion complexes with 1,8-diaminonapthalene-2-thione: Synthesis, Spectroscopic, anti-bacterial and anticancer activity studies Ahmed S. Faihan a,∗ , Mohammad R. Hatshan b , Ali S. Alqahtani c,d , Fahd A. Nasr c , Subhi A. Al-Jibori a , Ahmed S. Al-Janabi e a Department of Chemistry, College of Science, Tikrit University, Tikrit, Iraq b Department of Chemistry, College of Science, King Saud University, Riyadh, KSA, PO. Box 2455, Riyadh 11451, Saudi Arabia. c Medicinal, Aromatic and Poisonous Plants Research Center, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia d Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia e Department of Biochemistry, College of Veterinary Medicine, Tikrit University, Tikrit, Iraq a r t i c l e i n f o Article history: Received 4 July 2021 Revised 9 August 2021 Accepted 11 August 2021 Available online 13 August 2021 Keywords: Thiones 1,8-diaminonaphthalene-2-thione anti-bacterial anti-cancer a b s t r a c t Treatment of two molar equivalents of 1,8-diaminonaphthalene-2-thione with one molar equivalent of the metal’s(II) salt (Pd, Pt, Hg, Cd, Zn) afforded both neutral thione complexes and thionate derived com- plexes. The prepared ligand and its complexes (1-8) were characterized via different spectroscopic tech- nics including: FT-IR, 1 H, 13 C-NMR, and mass spectroscopy. The spectroscopic data analysis suggested that these compounds adopt different structural geometries. For instance, Pd(II) and Pt(II) complexes show square planar geometry. Whereas, thione complexes of Hg(II), Zn(II), and Cd(II) showed probable tetra- hedral structure. However, thionate derived complexes of Hg, and Ph-Hg are expected to be linear. The thionato-Cd(II) complex show bidentate chelating mode through its N and S donor atoms. Furthermore, the newly prepared complexes exhibit nano-structural characteristics, which were measured by SEM and X-Ray diffraction of the powder. SEM data showed that complexes from (3, 5) and (8) gave irregular nano-structure, nano-rod structure, and nano-sphere structural pattern respectively. On the other hand, Complexes (1) and (2) were tested against MCF-7 (breast) and LoVo (colon) cancer cells using MTT as- say. It was found that the palladium complex showed a promising antiproliferative activity against colon (LoVo) and breast (MCF-7) cancer cells with IC 50 values 21.13 and 22.25 μM respectively. In addition the anti-bacterial activity was study against two different pathogenic bacteria, and the Pd(II) complex dis- played highest activity compared with other complexes. © 2021 Elsevier B.V. All rights reserved. 1. Introduction Thiones are important compounds and known to have very interesting chemistry [1]. Thiones can adopt different coordina- tion modes due to their multi-donor atoms. For instance, co- ordination through S,N donor atoms are common in thiones at which S,N atoms binds to central metal in chelating mode or bind through S,N as a bridging mode with binuclear structure (Chart 1) [1]. However, S,N-bridging mode is find to be more stable [2]. This interesting feature enabled thiones to be part of wide range of applications such as medical, biological, analytical, and mate- rial science applications [3]. Thione complexes have been stud- ied extensively with different transition and non-transition met- ∗ Corresponding author. E-mail address: a-s.fehan@tu.edu.iq (A.S. Faihan). als, more specifically Mercury, Silver, Gold, Copper, Zinc, Palla- dium and Platinum [4–34]. Those prepared complexes showed interesting structural geometries. For instance, Hg(II), Cd(II), and Zn(II) can adopt monomeric or binuclear form with mainly tetra- hedral geometry depending upon the reaction conditions and mo- lar ration of the reactants [1,7]. On the other hand, Palladium or Platinum-thione complexes showed mono-dentate or binuclear be- havior with mainly square-planar geometry [10]. Just recently, new thiones have been reported, including 1,8- diaminonapthalene-2-thione which is analogous to benzimidazole- 2-thione. Surprisingly, no metal complexation has been reported yet (Chart 1(ii)) [8]. Imidazoline-2-thione and its derivatives are considered weak acids with PKa of 11 [5]. They can easily be deprotonated by aqueous sodium or potassium hydroxide to give thionate conjugate base which is electron rich ligand [6,7]. In this project, we are interested in both thione and thionate form. Our work was mainly focused on the preparation of divalent https://doi.org/10.1016/j.molstruc.2021.131291 0022-2860/© 2021 Elsevier B.V. All rights reserved.