Solvothermal preparation of nano cobalt sulfide from tris (cyclohexylpiperazinedithiocarbamato)cobalt(III) and characterization, single crystal X-ray crystal structure of the precursor

Abstract

Solvothermal formation of CoS nano particles is reported with a cobalt(III) dithiocarbamate as a single source precursor. Morphology and composition of the nano product have been characterized by PXRD and EDX analysis. Four unsymmetrically substituted tris cobalt(III) compounds, [Co(chmdtc)3] (1), [Co(chedtc)3] (2), [Co(achdtc)3] (3), and [Co(chpdtc)3] (4) (where chmdtc = cyclohexylmethylcarbodithioate, chedtc = cyclohexylethylcarbodithioate, achdtc = allylcyclohexylcarbodithioate and chpdtc = cyclohexylpiperazinecarbodithioate) were synthesized and characterized. Compounds (1)– (4) show bands at 634, 642, 635, and 643 nm respectively, due to d-d transitions. One electron quasi reversible reductions due to Co(III)/Co(II) redox process are observed in CV. In the 13C NMR spectra of the complexes, the thioureide (N13CS2) carbons resonate between 203.8 and 205.7 ppm. The observed deshielding of the –CH2 protons in 1H NMR of the compounds is attributed to the shift of electron density on the sulfur (or the metal) through the thioureide π system. TGA supported the proposed formulas of the compounds. Single crystal X-ray structure of [Co(chpdtc)3] (4) shows that the cobalt is in a distorted octahedral environment. Bond Valence Sum (BVS) calculations confirmed the formal oxidation state of cobalt as +3.