Aylin, U. and Coles, Simon J. and Davies, David B. and Eaton, R.J. and Hursthouse, Michael B. and Kiliç, A. and Shaw, Robert A. (2005) Stereoisomerism in pentaerythritol-bridged cyclotriphosphazene tri-spiranes: spiro and ansa 1,3-propanediyldioxy disubstituted derivatives. European Journal of Inorganic Chemistry 2005 (6), pp. 1042-1047. ISSN 1434-1948.
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Four isomeric products were isolated and purified from the reaction of 1,3-propanediol with the tetra-spirane cyclophosphazene-organophosphate compound (1): viz. the di-monospiro (2a), di-monoansa (2b) and two monospiro-monoansa derivatives (2c) and (2d). It is shown by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) that both the di-monospiro (2a) and di-monoansa (2b) derivatives are racemates, as expected, whereas no splitting of NMR signals occurred on addition of CSA to solutions of (2c) and (2d). It is found by X-ray crystallography that the two monospiro-monoansa spirane derivatives, (2c) and (2d), are meso diastereoisomers, which represent a new case of the stereochemistry of bis di-substituted cyclophosphazene derivatives of (1). It is also observed from the 31P NMR spectrum of the reaction mixture, supported by the yields of pure compounds, that formation of a spiro group is about 4.5 times more likely than that of an ansa moiety under the conditions of the reaction.
|Additional Information:||Available from http://www.interscience.wiley.com/|
|Keyword(s) / Subject(s):||cyclotriphosphazene derivatives, trispiranes, NMR spectroscopy, tetraspiranes, x-ray diffraction|
|School or Research Centre:||Birkbeck Schools and Research Centres > School of Science > Biological Sciences|
|Depositing User:||Sandra Plummer|
|Date Deposited:||07 Jun 2006|
|Last Modified:||17 Apr 2013 12:32|
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