Adduct degradants, case studies

Under the attack of one equivalent OH in H2O, MeO in MeOH, or pure NH3 a silicon vertex was removed from the c/oso-cluster l.[21 A plausible mechanistic sequence for the degradation involves as the first step formation of an adduct consisting of the nucleophile and the c/oso-cluster. Afterwards this adduct should react with a protic solvent to give the isolated reaction product. In order to get indications for the expected adduct we studied the attack of nucleophiles in an aprotic solvent. Three types of nucleophiles were studied in this reaction. In the case of the dialkylamide nucleophile best results were achieved from the reaction of the close-cluster with transition metal amides of zirconium and tantalum,17,81 The anionic adduct cluster features a dialkylamide bridging both silicon centres of the silaborane cluster. 

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