Berry exchange coordinate geometry in 3-methyl-2-hydroxycyclopenten-1-one tin esters

Three new penta- and hexacoordinated tin compounds (1–3) were prepared from PhSnCl3, Ph2SnCl2 and Ph3SnOH and 3-methyl-2-hydroxy-2-cyclopenten-1-one (L). Compounds 1–3 were characterized by IR, mass spectra, elemental analysis, 1H, 13C, and 119Sn NMR. The ligand acts as a bidentate giving the tin esters and coordinating the tin by the carbonyl group. Compound 1 (PhSnCl2L · EtOH) has an hexacoordinated tin atom, with an octahedral distorted geometry, which is a stereogenic center. Compounds 2 (Ph2SnClL) and 3 (Ph3SnL) have pentacoordinated tin atoms. The structures were determined by X-ray diffraction analyses. In the solid state 1 presents a racemic pair, linked by strong hydrogen bonds and 2 and 3 “Berry exchange coordinate” geometry.