Antimony(III) dithiocarbamates: Crystal structures, supramolecular aggregations, DNA binding, antioxidant and antileishmanial activities

Herein, we report the synthesis and characterization of four piperazine based homoleptic antimony(III) dithiocarbamates, i.e. Sb[S₂CN(CH₂)₄N(Bn)]₃ (1), Sb[S₂CN(CH₂)₄NCH-(Ph)₂]₃ (2), Sb[S₂CN(CH₂)₄N(2-MeO-C₆H₄)]₃ (3) and Sb[S₂CN(CH₂)₄N(C₆H₄-NO₂)]₃.CH₂Cl₂ (4), by means of elemental analysis and many spectroscopic techniques, like FT-IR, NMR (¹H and ¹³C) and single crystal XRD. The XRD data revealed a distorted 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 pyramidal 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, antioxidant, 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, complex 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.