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Physical properties of organic thiones: Part IV. The basicity of the thiocarbonyl group in various thiones

1962; Royal Netherlands Chemical Society; Volume: 81; Issue: 8 Linguagem: Inglês

10.1002/recl.19620810803

1878-7096

M. J. Janssen,

Thermal and Kinetic Analysis

Abstract The basicities of four N , N ‐dimethylthioamides, of thiourea and all the N ‐methylated thioureas, of ethylenethiourea, N , N ′‐dimethylethylenethiourea and trimethylenethiourea, of S ‐methyl N , N ‐dimethyldithiocarbamate and ‐dimethyl trithiocarbonate, were determined. Measurements were made spectrophotometrically in aqueous sulphuric acid of various strengths and attempts were made to correct the absorption values for solvent effects. In methylated thioureas both electronic and steric effects influence the acidity constants. These effects appear to be of comparable magnitude. The results on the dithiocarbamate and trithiocarbonate show that in these compounds the basicity is determined by the negative inductive rather than by the positive mesomeric effect of the methylmercapto group. The amino group exerts a strong mesomeric action as expected.