The conformations and 1H nuclear magnetic resonance parameters of dibenzylideneacetone
- 1 January 1978
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 3,p. 231-235
- https://doi.org/10.1039/p29780000231
Abstract
Dibenzylideneacetone, (C6H5CHCH)2CO, with two degrees of rotational freedom imparted by the two single bonds between the olefin and the carbonyl group was studied to determine its stable conformers by 1H n.m.r. spectroscopy and by an INDO molecular orbital method. A solvent effect induced by benzene on the trans-olefinic protons and a least squares analysis of the temperature dependence of the internal chemical shift (δAB) between the olefinic protons have revealed support of the theoretical calculations of δAB that the major conformation is s-cis,cis and the minor one is s-cis,trans. An INDO calculation of the conformers concerned confirmed this deduction together with the absence of the s-trans,trans form. δAB is a characteristic parameter of the conformation with the values 0.5 and 1.5 p.p.m. for the s-cis and s-trans forms, respectively, in the olefinic portions of dibenzylideneaċetone.Keywords
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