Initial organotin chemistry

•The first organostannane was found in search of isolation of free ethyl groups.•The initial products Et2SnI2 and (Et2Sn)n acted as a basis of organotin chemistry.•Within 10 years different organotin compounds and reactions routes were established.

In 1849, attempts to isolate free alkyl groups led to discovery of an organostannane, (C2H5)2SnI2, which was analyzed in 1852. Coevally, aims at extension of trialkylstibine and trialkyl bismuth chemistry yielded [(C2H5)2Sn]n, finally consisting rather of (cyclic) oligostannanes than polystannanes; the latter might have been degraded to the former though. Further, those reports described conversion of (C2H5)2SnI2 or [(C2H5)2Sn]n to (C2H5)2SnO, in fact a polymer, [(C2H5)2SnO]n. These three substances were employed as starting materials for exploration of new alkylstannanes, and moreover some of the compounds thus obtained were used for synthesis of other organostannanes. Thus, e.g., dialkylstannanes (C2H5)2SnX2 (X = Br, Cl, nitrate, formate, acetate) and a number of corresponding methyl derivatives were prepared, as well as (C2H5)2SnSO4, (CH3)2SnSO4, (C2H5)2Sn(C2O4) and tetraalkylstannanes. Dinuclear tin compounds were also addressed, in particular (C2H5)3Sn–Sn(C2H5)3, (C2H5)2ISn–Sn(C2H5)2I, and (C2H5)3SnOSn(C2H5)3. The latter arose as a reversibly formed dehydration product of (C2H5)3SnOH. This hydroxide and (CH3)3SnOH served for the synthesis of trialkylstannanes R3SnX (R = ethyl: X = Br, Cl; R = ethyl or methyl: X = formate, acetate, butyrate), [(C2H5)3Sn]2SO4, [(CH3)3Sn]2SO4 and [(C2H5)3Sn]2(C2O4). Among the synthesis routes substitution and addition reactions were applied, and even the so-called Kocheshkov redistribution reaction (Kocheshkov comproportionation) was already described, namely by Buckton who thus obtained (C2H5)3SnCl. Hence, already by 1860 a diversity of organotin compounds and related reactions was established, and the base for methodical exploration of organotin compounds was laid.

Graphical abstractAround 1850, the first organostannanes were generated in search of isolation of free alkyl groups and extension of trialkylstibine and trialkyl bismuth chemistry. Thereby, (C2H5)2SnI2 and [(C2H5)2Sn]n were discovered, which served as sources of other organotin compounds. Thus, within ten years a firm basis of organotin chemistry was established.Figure optionsDownload full-size imageDownload as PowerPoint slide