The structure of aqueous pentaoxo silicon complexes with m-1,2-dihydroxycyclopentane and furanoidic vicinal m-diols

摘要

Addition of cis-l,2-dihydroxycyclopentane to aqueous alkaline silicate solutions results in the spontaneous formation of three organosilicate species,each with a 2:1 ligand to Si ratio and a pentacoordinated silicon centre.By using a mixture of both cis-l,2-dihydroxycyclopentane and 1,4-anhydroerythritol we show unambiguously that all three species are diastereomers of the monomeric bis(diolato)-hydroxo complex,[(L=)_2SiOH]~(where L represents the cis-diol ligand),thus clarifying the general assignment of ~(29)Si NMR spectra reported for silicate solutions containing furanoidic sugars with vicinal cis-diol functionality,such as ribose.