We have been developing the chemistry of zwitterionic carb- silyl and germyl anions also referred to as zwitterionic metal tetrelides. These organometallic species represent a structurally novel class of rigid zwitterions, in which the cationic metal center is rigidly locked and charge-separated from the tri-coordinated tetrelide anion by internal polydonor bridges. In striking contrast to the well-documented family of tetra-coordinate borate-based zwitterions, our tri-coordinate zwitterionic tetrelides have a stereochemically active electron pair localized at the central tetrelide anion, which is available for additional metal binding and allows for the convenient generation of hetero-bimetallic zwitterions. For example, reactions of the silanides and germanides with metal carbonyls, M(CO)n give with loss of one molecule of CO stable hetero-bimetallic zwitterions. In the presence of Lewis acidic organoboranes, BR3, novel zwitterionic borates are formed.Remarkably, our zwitterionic carbanions form frustrated Lewis pairs (FLP's) with a variety of boranes ranging from Mes2BF and BPh3 to weakly Lewis acidic alkyl boranes (BR3) and alkylborates, B(OR)3. Cleavage of dihydrogen with these novel FLP's occurs readily to give alkali metal borate salts. The synthetic utility and reactivity of this novel class of FLP's will be discussed.

Zwitterionic carb- and silyl anions: Synthesis, structure, reactivity and FLP chemistry

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.