Antimony(III) dithiocarbamates: Crystal structures, supramolecular aggregations, DNA binding, antioxidant and antileishmanial activities Faisal Hayat a,b,c,1 , Syed Niaz Ali Shah a,1 , Zia ur Rehman a,⇑ , Francine Bélanger-Gariepy d a Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan b Department of Chemistry, The University of Azad Jammu & Kashmir, Muzaffarabad, Pakistan c Department of Chemistry, University of Kotli Azad Jammu and Kashmir, Kotli, AK, Pakistan d Département de Chimie, Université de Montréal, Montreal, Canada article info Article history: Received 28 July 2020 Accepted 3 November 2020 Available online 13 November 2020 Keywords: Antimony(III) dithiocarbamates Supramolecular DNA binding Antioxidant Antileishmanial activity abstract Herein, we report the synthesis and characterization of four piperazine based homoleptic antimony(III) dithiocarbamates, i.e. Sb[S 2 CN(CH 2 ) 4 N(Bn)] 3 (1), Sb[S 2 CN(CH 2 ) 4 NCH-(Ph) 2 ] 3 (2), Sb[S 2 CN(CH 2 ) 4 N(2-MeO- C 6 H 4 )] 3 (3) and Sb[S 2 CN(CH 2 ) 4 N(C 6 H 4 -NO 2 )] 3 .CH 2 Cl 2 (4), by means of elemental analysis and many spec- troscopic techniques, like FT-IR, NMR ( 1 H and 13 C) and single crystal XRD. The XRD data revealed a dis- torted trigonal antiprismatic geometry around the central antimony atom for 2 and 3, with the trigonal space groups R-3 and R3c respectively, while a distorted pentagonal pyramidal geometry was found for 4, with the triclinic space group P-1. The trigonal antiprismatic complexes (2 and 3) feature fascinating 2-D supramolecular layers, extending into 3-D networks in a stacked fashion, while for the pentagonal pyra- midal complex 4, the dimensionality is lowered to linear chains. Some of these complexes (1, 2 and 4) were further checked for their biological potential (DNA binding, using UV–Visible spectroscopy, antiox- idant, cytotoxic and antileishmanial). They showed moderately stronger binding with the DNA base-pairs via the intercalative mode, as suggested by hypochromism in their electronic spectra. Interestingly, com- plex 2 was more active than the standard drug ascorbic acid for its antioxidant action, while complex 4 showed high activity in both the cytotoxic and antileishmanial assays. Ó 2020 Elsevier Ltd. All rights reserved. 1. Introduction Medicinal use of antimony compounds dates back to the 16th and 17th centuries, e.g. antimony(III) potassium tartrate (tartar emetic) was used to cure many diseases, like lung diseases (pneu- monia), typhoid and snail fevers etc. [1]. Recently, at least three antimonials are under clinical use, i.e. Stibophen, Pentostam (sodium stibogluconate) and Glucantime (meglumine antimoni- ate), the latter being recommended by WHO as the first-choice drug against all types of leishmaniasis [1–7]. Despite this long therapeutic history of such compounds, it is surprising that they have been given much less attention in the past, e.g. dithiocarba- mates have been medicinally well-known for a long time but their antimony complexes have been little studied. Until now, no report on the antileishmanial assay of antimony dithiocarbamates is available [6]. However, on getting some focus in recent times, many antimony compounds have been synthesized with very promising biological potential [6,7], i.e. antimony aminocarboxylic acids showed excellent antineoplastic activity [8,9], while some related compounds featured high biological potential [7,10] and have been applied medically [3,11]. As far as dithiocarbamate com- plexes are concerned, two dimethyl substituted polymorphs, [SbCl (S 2 CNMe 2 ) 2 ] n , were extremely active against MCF-7 cancer cell lines, with IC 50 -values in the nanomolar range [12,13]. Remarkably, this activity was greater than the FDA approved drugs cisplatin [14,15] and doxorubicin [13]. They showed 21–53 and 158–340 times greater cytotoxicity than cisplatin against HeLa and MCF-7 cell lines, respectively [16]. This data clearly indicates the great potential of antimony compounds and hence demands their fur- ther exploration in the biological domain. Various solid state crystal structures of antimony(III) dithiocar- bamates have been studied in the past few years [17] owing to their distinct applications either related to chemical or biological endeavors. Many of such complexes exhibit peculiar and occasion- ally surprising features [18]. Interest in such compounds arises not only due to their promising biological potential but also due to their entrancing solid-state supramolecular architectures [19,20]. A systematic evaluation of supramolecular aggregation patterns https://doi.org/10.1016/j.poly.2020.114909 0277-5387/Ó 2020 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: zrehman@qau.edu.pk, hafizqau@yahoo.com (Z.ur Rehman). 1 Faisal Hayat and Syed Niaz Ali Shah contributed equally. Polyhedron 194 (2021) 114909 Contents lists available at ScienceDirect Polyhedron journal homepage: www.elsevier.com/locate/poly