Dirac vector model and variational treatments of proton spin-spin coupling across three bonds |
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| Authors: | P Chandra PT Narasimhan |
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| Institution: | 1. Department of Chemistry , Indian Institute of Technology , Kanpur, U.P.;2. Department of Chemistry , Banaras University , Varanasi 5, India |
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| Abstract: | The Dirac vector model and variational treatments have been used to study the angular dependence of proton spin couplings across three bonds in fragments of the type H-X-Y-H (X, Y = C, N, O). These couplings can be expressed by means of the relation J(φ) = A + B cos φ + C cos2 φ, where φ is the dihedral angle and A, B and C are constants. It is seen that the behaviour of various fragments towards substituents can be qualitatively predicted by looking at the sign of the constant B. |
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