Organomercury Compounds. XVI. Thermal decomposition reactions of mercuric arenesulphonate dihydrates

Abstract

Thermal decomposition of the mercuric arenesulphonate dihydrates Hg(03SR)2,- 2H20 (R = C6X5, p-HC6X4, or m-HC6C14; X = C1 or F) at c. 130-240" gave the corresponding diarylmercurials, the polyhalogenobenzenes RH, and sulphur trioxide (or sulphuric acid) in all cases, together with RS03H (R = C6F5 or p-HC6F4), and p-(p-HC6F4S03Hg),C6F4. By contrast, decomposition of Hg(03SR)2,2H20 (R = m-HC6F4 or o-HC6X4) gave the corresponding (-HgC6X4S03-), derivatives, sulphonic acids, polyhalogenobenzenes, and sulphur trioxide in all cases, together with m-HC6F4HgO3S-m-HC6F4 and o-(o-HC~C~~SOJH~),C~C~~. The compounds RHg03SR (R = C6C15, isolated as the monopyridinate, or p-HC6C14) were obtained from decomposition of the appropriate mercuric sulphonates at c. 165'. Identities of (-HgC6X4S03-), derivatives were established mainly by cleavage with triiodide ions in N,N-dimethylformamide giving the salts M(IC6X,S03) (M = Na or S-benzylthiouron- ium), and of (HC6X4S03Hg)2C6X4 derivatives by similar degradation giving 12C6X4 and M(HC6X4S03) (M = Na or Ph4As). Similar degradation of C6C15Hg03SC6C15,py, p-HC6Cl,Hg03S-p-HC6C14, and the known mercurials C6C15HgCl, (p-HC6C14),Hg, and (0-HC6C14),Hg gave the corresponding iodopolychlorobenzenes. The mercurated derivative (-o-H~C,F~SO~-)~ gave (-0-HgCsF4-)3 on thermal decomposition, and crystallization from water yielded ( - o - H ~ C ~ F ~ S ~ ~ - ) , , ~ ~ H ~ ~ , which was converted into (Ph4As)(o-C1HgC6F4S03) by tetraphenylarsonium chloride. The mercuric sulphonates were prepared from mercuric acetate and the appro- priate sulphonic acids in acetic acid (X = C1) or water (X = F). Sulphonic acids, obtained by sulphonation reactions, were characterized as the dihydrates and in some cases sodium salts (polychloro derivatives) or as barium and tetraphenylarsonium salts (tetrafluoro derivatives).