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Steric trends and kinetic parameters for radical reductions involving alkyldiphenyltin hydrides

Dakternieks, D., Henry, D.J.ORCID: 0000-0002-9629-4423 and Schiesser, C.H. (1999) Steric trends and kinetic parameters for radical reductions involving alkyldiphenyltin hydrides. Journal of Physical Organic Chemistry, 12 (3). pp. 233-239.

Link to Published Version: http://dx.doi.org/10.1002/(SICI)1099-1395(199903)1...
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Abstract

Absolute rate constants and Arrhenius parameters for hydrogen atom abstraction by primary alkyl radicals from methyldiphenyl-, ethyldiphenyl-, butyldiphenyl-, isopropyldiphenyl-, cyclohexyldiphenyl- and (trimethylsilyl)methyldiphenyltin hydride were determined in tert-butylbenzene through utilization of the ‘5-hexenyl radical clock’ reaction. At 80 °C, rate constants (kH) for all hydrides were found to lie in the range (8.2–11.5) × 106 lmol−1 s−1, with similar Arrhenius expressions for all reactions studied [viz. log kH = (8.92–8.97)−(3.03–3.24)/2.3RT]. The nature of the alkyl substituent appears to have a subtle effect on the function of the hydride such that the order or reactivity of stannanes (RPh2SnH) is Me > Et > Bu > i-Pr > c-Hex ≥ Me3SiCH2; this trend can be directly traced to steric effects operating in the transition states for hydrogen transfer from tin to carbon. The implications of these observations are discussed.

Item Type: Journal Article
Publisher: John Wiley & Sons, Ltd
Copyright: © 1999 John Wiley & Sons, Ltd
URI: http://researchrepository.murdoch.edu.au/id/eprint/4966
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