Synthesis, spectral, biological applications on cobalt(III) dithiocarbamate complexes and their solvothermal decomposition to nano cobalt(II) sulphide

A.S. Sonia*, R. Baskaran
Department of Chemistry, Annamalai University, Annamalai Nagar, T.N, India-608 002.

A B S T R A C T
Octahedral diamagnetic [Co(eedtc)₃] (1), [Co(medtc)₃] (2), [Co(bhpdtc)₃] (3) and [Co(cedtc)₃](4) (where eedtc = N-ethyl-N-(2-hydroxyethyl) dithiocarbamate anion, medtc = N-methyl-N-(2-hydroxyethyl) dithiocarbamate anion, bhpdtc =N-benzhydryl piperazine dithiocarbamate anion and cedtc = bis(2-cyanoethylamine)  dithiocarbamate anion) have been prepared. The synthesized complexes 1–4 are characterized by elemental analysis, thermal analysis and spectroscopic methods (IR, UV-Vis and ¹H & ¹³C NMR). The IR spectra suggest the coordination of dithiocarbamate occurred through the two sulphur atoms in a symmetrical bidendate fashion. Electronic spectra of the complexes show signature bands corresponding to d-d transition. One electron quasi reversible reductions which are due to Co (III)/Co (II) redox process are observed in cyclic voltammetry. Final residue obtained in thermal analysis is CoS, indicates the reduction of Co(III) → Co(II). A non conventional solvothermal formation of CoS nano particles is reported with cobalt dithiocarbamate as single source precursor. Morphology and composition of the nano product have been characterized by pXRD, SEM and EDX analysis. The antibacterial activities of synthesized complexes were studied against two gram negative species, Escherichia coli, Pseudomonas aeruginosa and three gram positive species, Streptococcus pyogenes, Staphylococcus aureus and Bacillus subtilis and for in vitro antifungal activity against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Penicillium chryogenum and Trigoderma veride.
Keywords: dithiocarbamate, cobalt(III), thioureide, decomposition study, biological applications, nano sulfide