Characterization of tetra-aryl benzene isomers by using preparative gas chromatography with mass spectrometry, nuclear magnetic resonance spectroscopy, and x-ray crystallographic methods

Christian Ruhle, Julie Niere, Paul Morrison, Roderick Jones, Tom Caradoc-Davies, Allan Canty, Michael Gardiner, Vicki-Anne Tolhurst, Philip Marriott

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Abstract

The present study describes a preparative gas chromatographic (GC) approach employed to study a series of products arising from reaction of phenylacetylene with para-substituted aryl-iodides under Sonogashira catalysis conditions. GC analysis resolves the isomers from each reaction; however, it cannot provide structural details (their MS data are virtually identical). Since classical liquid chromatography cannot resolve the isomers, preparative-scale GC is the only practical approach to provide further spectroscopic characterization of the isomers. The products are well separated by GC so a single thick-film capillary column is adequate for this case, with operation up to similar to+300 degrees C. By collection of 50+ repeat injections, sufficient material could be isolated for H-1 NMR spectral analysis of the isomers, and for one isomer (isomer I) of a number of analogous related catalytic reaction mixtures, X-ray crystal structure determination enabled complete structural elucidation (absolute configuration) of the substitution pattern of the structure of this isomer. This confirmed isomer I to be the 2-para-aryl-substituted 1,3,5-triphenylbenzene product in all cases. 1H NMR spectra of isomer I products generally had similar patterns but differed markedly from the second major isomer product (isomer II).
Original languageEnglish
Pages (from-to)4501 - 4509
Number of pages9
JournalAnalytical Chemistry
Volume82
Issue number11
DOIs
Publication statusPublished - 2010
Externally publishedYes

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