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Gas‐phase nucleophilic reactions in tetraalkoxysilanes
Author(s) -
da Silva Maria Lucia Pereira,
Riveros José M.
Publication year - 1995
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1190300512
Subject(s) - chemistry , nucleophile , gas phase , phase (matter) , organic chemistry , computational chemistry , catalysis
The gas‐phase reactions of F − , OH −· , OH − , EtO − , NH 2 −and EtNH − with Si(OEt) 4 were investigated by Fourier transform ion cyclotron resonance in order to probe the intrinsic reactivity of substrates used in plasma chemical vapour deposition. Isotopic data and the nature of the product ions suggest that reactions proceed primarily by attack of the nucleophile on the silicon centre. The ensuing chemistry can be explained by the fragmentation pathways available to the [XSi(OR) 4 ] − intermediate, which includes alkoxide displacement, internal nucleophilic displacement and cyclic elimination of ethylene in the ethoxy case. Pentacoordinated adducts are observed in the reactions with F − and in the symmetric alkoxide/tetraalkoxysilane reactions. The reaction of F − with Si(OMe) 4 is also shown to produce a perplexing ion of unknown structure and identified as [FSi(OMe) 2 (OCH 2 )] − .