Cleavage of silicon-carbon bonds and relative rates of hydrolysis of ormosil precursors for optical materials

Authors

  • Angela B. Seddon,

    1. Glass Research Group and Centre for Molecular Materials, Department of Engineering Materials, PO Box 600, Sir Robert Headfield Building, The University, Mappin Street, Sheffield S1 4DU, U.K.
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  • Suzane Hunt,

    1. Glass Research Group and Centre for Molecular Materials, Department of Engineering Materials, PO Box 600, Sir Robert Headfield Building, The University, Mappin Street, Sheffield S1 4DU, U.K.
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  • Jonathan P. Rourke,

    1. Centre for Molecular Materials and Department of Chemistry, The University, Sheffield S3 7HF, U.K.
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  • Duncan W. Bruce

    1. Centre for Molecular Materials and Department of Chemistry, The University, Sheffield S3 7HF, U.K.
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    • Dr. Duncan W. Bruce is the Sir Edward Frankland Fellow of the Royal Society of Chemistry 1994-95


Abstract

1H NMR spectroscopy of methyltrimethoxysilane (MTMS) has revealed that cleavage of the Si—C bond occur during hydrolysis in the presence of HCI. A mechanism is suggested involving nuleophillic attack by CI with electrophilic promotion. Optical materials based on tetramethoxysilane (TMOS) and MTMS are vsually transparent and 1H NMR reveals the similarity of the hydrolysis rates of these precursors under acid catalysis. 1H NMR indicates that residual unhydrolysed methoxide groups in the finished optical materials are a possibility.

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