Bis(N′-{(E)-[(2E)-1,3-diphenylprop-2-en-1-ylidene]amino}-N-ethylcarbamimidothioato-κ²N′,S)zinc(II): crystal structure and Hirshfeld surface analysis

Abstract

The title Zn II complex, [Zn(C 18 H 18 N 3 S) 2 ], (I), features two independent but chemically equivalent molecules in the asymmetric unit. In each, the thiosemicarbazonate monoanion coordinates the Zn II atom via the thiolate-S and imine-N atoms, with the resulting N 2 S 2 donor set defining a distorted tetrahedral geometry. The five-membered ZnSCN 2 chelate rings adopt distinct conformations in each independent molecule, i.e. one ring is almost planar while the other is twisted about the Zn-S bond. In the crystal, the two molecules comprising the asymmetric unit are linked by amine-N-HÁ Á ÁN(imine) and amine-N-HÁ Á ÁS(thiolate) hydrogen bonds via an eight-membered heterosynthon, {Á Á ÁHNCNÁ Á ÁHNCS}. The dimeric aggregates are further consolidated by benzene-C-HÁ Á ÁS(thiolate) interactions and are linked into a zigzag supramolecular chain along the c axis via amine-N-HÁ Á ÁS(thiolate) hydrogen bonds. The chains are connected into a three-dimensional architecture via phenyl-C-HÁ Á Á (phenyl) and -interactions, the latter occurring between chelate and phenyl rings [inter-centroid separation = 3.6873 (11) Å ]. The analysis of the Hirshfeld surfaces calculated for (I) emphasizes the different interactions formed by the independent molecules in the crystal and the impact of theinteractions between chelate and phenyl rings. Chemical contextThiosemicarbazone molecules, derived from thiosemicarbazide, H 2 N-NH-C( S)-NH 2 , constitute an important class of mixed hard-soft, nitrogen-sulfur donor ligands which have been extensively investigated in their coordination chemistry towards both transition metals (Lobana et al., 2009) and main group elements (Casas et al., 2000). Complexes of thiosemicarbazones, including Zn II complexes (Da Silva et al., 2013), have been evaluated variously as potential anti-cancer (Afrasiabi et al., 2003), anti-viral (Garoufis et al., 2009) and anti-bacterial (Quiroga & Ranninger, 2004) therapeutics for over 50 years (Dilworth & Hueting, 2012). The interesting properties of their metal complexes, such as structural diversity, accessible redox activities, the ability to fine-tune ligand substitution, access to radical species, catalytic properties, distinct spectroscopic properties, etc. afford them many potential advantages over organic-based drugs (van Rijt & ISSN 2056-9890 Sadler, 2009Meggers, 2009). Recent studies have focused upon their suitability as single-source precursors for ZnS nanomaterials (Pawar et al., 2017). Thiosemicarbazones can exist as thione-thiol tautomers and can bind to a metal centre in neutral or anionic forms as monodentate, bidentate or bridging ligands (Viñ uelas-Zahínos et al., 2011). The presence of additional, suitably positioned donor atoms can increase their coordination ability/denticity, giving rise to different coordination geometries, such as tetrahedral, octahedral and pentagonal-bipyramidal. (Umamatheswari et al., 2011). As part of a programme investigating thiosemicarbazones and their metal complexes (Tan et al., 2015), the crystal and molecular s...

Bis(4-methoxychalcone 4-ethylthiosemicarbazonato-κ2 N 1,S)zinc(II): crystal structure and Hirshfeld surface analysis

“…Such considerations motivate our interest in this class of compound (Yusof et al, 2015). Herein, in ISSN 2056-9890 continuation of our structural studies of Zn II thiosemicarbazones (Tan et al, 2017), the X-ray crystal structure of the title compound, (I), is described along with an analysis of its Hirshfeld surfaces in order to gain more information on the mode of association between molecules in the molecular packing.…”

“…The Hirshfeld surfaces calculated for (I) were performed in accord with recent work on a related complex (Tan et al, 2017) and provide more insight into the intermolecular interactions occurring in the crystal. The donors and acceptors of the intermolecular N-HÁ Á ÁS hydrogen bonds are viewed as bright-red spots, labelled as '1 ' and '2' in Fig.…”

1-{(E)-[(2E)-3-(4-Methoxyphenyl)-1-phenylprop-2-en-1-ylidene]amino}-3-phenylurea: crystal structure and Hirshfeld surface analysis

“…The present work is part of an on-going project on the synthesis of chalcone-derived Schiff bases, their ultilization in the synthesis of new transition metal complexes and their investigation as anti-proliferative and anti-bacterial agents. In this context, crystal-structure determinations of a chalcone-derived thiosemicarbazone and a zinc complex have been published (Tan et al, 2015(Tan et al, , 2017.…”

“…The Hirshfeld surface was calculated for (I) in accord with a recent report on a related molecule (Tan et al, 2017) to provide more detailed information on the relative significance of the various intermolecular interactions. The donors and acceptors of intermolecular N-HÁ Á ÁO and C-HÁ Á ÁO interactions in (I) are viewed as the bright-red spots near the ethylene-H9, amide-H2N and carbonyl-O1 atoms on the Hirshfeld surface mapped over d norm in Fig.…”

Zwitterionic 1-{(1E)-[(4-hydroxyphenyl)iminio]methyl}naphthalen-2-olate: crystal structure and Hirshfeld surface analysis

“…The Hirshfeld surface was calculated for (I) according to earlier work on organic molecules (Tan et al, 2017) and provides more detailed information on the intermolecular interactions influential in the crystal. In addition to the brightred spots near those atoms participating in charge-assisted O1-H1OÁ Á ÁO2 and C7-H7Á Á ÁO1 interactions on the Hirshfeld surface mapped over d norm , Fig.…”