[Study on the reaction between cobalt tetrasulphonated phthalocyanine and sodium sulfide]

A new method which uses multi-wave number and double-parameter to analyse the UV-Vis. spectra is proposed to determine the composition and stabilization constants of coordination compounds. With this method, the reaction of cobalt tetrasulphonated phthalcyanine [CoTsPc] and sodium sulfide [Na2S] was studied. The result shows that pH of the medium has great effect on the reaction. A five coordinated compound Co(II)TsPc(HS) was formed at pH = 7.0. The equilibrium constants and thermodynamics are reported for the reaction under that condition. At higher pH, a redox-reaction took place and a five coordinated compound with the oxidation number I for cobalt [SCo(I)TsPc] was found.