Proton nuclear magnetic resonance spectra nonequivalence

Some interest is attached to the conformation of the metallocycle in solution, as either conformation VII or VIII are possible. In the former (VII), there is no symmetry plane plane containing the MCSiN-four membered ring, the methylene and Me2Si protons are chemically nonequivalent. In the latter case, (VIII), there is such a symmetry plane and the methylene and Me2Si protons are chemically equivalent. The room temperature and -80°C nuclear magnetic resonance spectrum is consistent... 

Nuclear magnetic resonance spectra could have been useful in the structural elucidation and identification of the K vitamins. This is demonstrated in Fig. 4 by the nuclear magnetic resonance spectrum of vitamin Kgcst). The different resonances in Fig. 4 can be attributed to all the nonequivalent protons in the molecule. The resonance at —12 cycles per second (c.p.s.) is... 

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