Cesium Reduction of a Lithium Diamidochloroberyllate

Room temperature reaction of elemental cesium with the dimeric lithium chloroberyllate [{SiNDipp}­BeClLi]2 [{SiNDipp} = {CH2SiMe2N­(Dipp)}2, where Dipp = 2,6-di-isopropylphenyl, in C6D6 results in activation of the arene solvent. Although, in contrast to earlier observations of lithium and sodium metal reduction, the generation of a mooted cesium phenylberyllate could not be confirmed, this process corroborates a previous hypothesis that such beryllium-centered solvent activation also necessitates the formation of hydridoberyllium species. These observations are further borne out by the study of an analogous reaction performed in toluene, in which case the proposed generation of formally low oxidation state beryllium radical anion intermediates induces activation of a toluene sp 3 C–H bond and the isolation of the polymeric cesium benzylberyllate, [Cs­({SiNDipp}­BeCH2C6H5)]∞.