The CpSi+ cation as a stoichiometric source of siliconThis article is part of the ChemComm 'Frontiers in Molecular Main Group Chemistry' web themed issue.Electronic supplementary information (ESI) available: Details of DFT studies of 3Ph, 3Ph, 8Ph, 3Dip, 3Dip and 8Dip. The primary computational data on 3Dip, 3Dip and 8Dip have also been deposited with the SPECTRa database and can be retrieved with the following identifiers (3Dip: 10042/to-13974 and 10042/to-13982; 3Dip: 10042/to-13969 and 10042/

The Cp*Si + cation acts as a stoichiometric source of silicon in the reaction with the disilenide Tip 2 Si=Si(Tip)Li (Tip = 2,4,6- i Pr 3 C 6 H 2 ) affording known neutral unsaturated silicon clusters. It thereby provides a conceptually different approach to this novel class of compounds. The proposed mechanism involves a Cp*-substituted cyclotrisilene in which Cp* acts as a leaving group upon single electron reduction or in a nucleophilic substitution step. Cp*Si + acts as a stoichiometric source of silicon in the reaction with a disilenide.