The esterificaiton of tin(II) oxide

Abstract

Aromatic o-hydroxy-ethers react with blue-black stannous oxide (1) to give o-phenylenedioxytin(II), water and the corresponding o-dialkoxy-benezene. Salicylic acid also reacts to produce a novel, six membered, tin(II)-containing ring system (3) for which infrared evidence shows intermolecular bonding through the carbonyl oxygen in the solid. (3) dissolves in and forms a 1:1 complex with triethylamine where the tin (II) atom is three-coordinate. Catechol produces (2) and hydrogen sulfide from stannous sulfide, suggesting (1) as the original of the water oxygen in these reactions. The esterification of hydrous tin(II) oxide 4 by catechol and o-methoxyphenol procees uncatalyzed to produce (2) Monofunctional alcohols (which require a catalyst) and phenols also reac with (4) to produce products of the composition RO(SnO)2R whre n = 1, 2 or 3 as shown by microanalytical and molecular weight data. These compounds hydrolyze to regenerate the starting alcohol or phenol. Ethylene glycol gives a polymer of the back-bone structure [OCH2CH2OSn]. The presence of tin(II) is established by treatment with mercuric chloride and by Sn119m Mössbauer spectroscopy. Mössbauer data indicate that slow hydrolysis in air is accompanied by oxidation to tin(IV) oxide. Catalysis in the alcohol in the alcohol reactions increases in effectiveness Cu>CuO>1:1Cu+Cu2O>Cu2O in competition with the dehydration of (4). Alkyl and arylthiols give tetrathiotin(IV) derivatives with (4) but with (1) thiophenol produces the simple tin(II) mercaptide. The insertion reactions of phenyl isocyanate with tin(II) dimethoxide and phenoxide yield tin(II) carbamate compounds with a tin(II)-nitrogen bond. The insertion of phenyl isocyante into the tin(II)-oxygen bonds of 2,2′ biphenylenedioxytin(II) results in ring expansion to a novel element-membered heterocycle. The reactions of tin(II) acetate with alcohols and phenols are also described.