Exploring the hydrogen-bonding interactions in the piperazinylethanol substituted homoleptic zinc(II)-dithiocarbamate and its diimine 2,2?-bipyridyl and 1,10-phenanthroline adducts, and their DNA binding studies

Keeping in view the significance of H-bonding hydroxyethyl substituent in the supramolecular organization of the compounds of general formula Zn(S 2 CNR 1 R 2 ) 2 , herein we report synthesis and characterization ( 1 H/ 13 C NMR, FTIR, UV-Vis spectroscopy, CV, elemental analysis and single crystal XRD) of piperazinylethanol substituted complex [Zn{S 2 CN(CH 2 ) 4 N(C 2 H 4 OH)} 2 ] 2 ( 1 ) and its 2,2 acute accent -bipyridyl ( 2 ) and 1,10-phenanthroline ( 3 ) adducts. Inferred from XRD data, these compounds show a variety of coordination geometries, i.e., Zn1-center ( Tau = 0.668) in ( 1 ) is more inclined towards trigonal-bipyramidal environment than the Zn2-center ( Tau = 0.567), whereas ( 2 ) and ( 3 ) exhibit distorted octa- and tetrahedral geometries, respectively. Unlike the others, complex ( 2 ) co-crystallized with an uncoordinated 2,2 acute accent -bipyridyl ligand showing more stable trans -conformation of the N-atoms. Supramolecular data reveal pivotal role of the H-bonding interactions in the crystal packing, especially in ( 1 ) where (hydroxyethyl)O -H middotmiddotmiddotO -H(hydroxyethyl) interaction sustains 3-D network. The interaction propagates in infinite open chain fashion and the network secures undulating topology. Adducts ( 2 ) and ( 3 ) also feature undulating topologies, however, O -H middotmiddotmiddotN H-bonding interaction plays the role to sustain 2- and 1-D networks, respectively. Other secondary bonding interactions, like C -H middotmiddotmiddotS, C -H middotmiddotmiddot7r(aromatic), C -H middotmiddotmiddotO and 7rmiddotmiddotmiddot7r stacking etc. contribute to transform these 1- and 2-D architectures into 3-D aggregates. Compared to closely related systems, these compounds show enhanced H-bonding potential with less hydroxyethyl substituents per molecule, possibly due to the presence of sterically flexible piperazine ring. Further, their DNA-binding capability was assessed through multiple techniques (like UV-vis spectroscopy, CV and viscometry), which revealed promising DNA binding potential for these compounds.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study reports the synthesis and characterization of a series of compounds with hydroxyethyl substituents, highlighting their importance in the supramolecular organization. The compounds exhibit different coordination geometries, and H-bonding interactions play a crucial role in the crystal packing.