H-1 NMR study on the products of the catalytic reduction of ethyne by nitrogenase in D2O

The products of the catalytic reduction ethyne by nitrogenase in D2O were s tudied by H-1 NMR. In order to assign the H-1 NMR spectrum, the theoretical spectra of C2H2D2 were calculated using group symmetry. The final eigenfun ctions, eigenvalues, allowed transitions and intensities of C2H2D2 and C2H3 D were obtained. It can be concluded that the products comprised mainly of cis-C2H2D2. There was also some C2H3D. 1H chemical shift in C2H3D moved by ca. 4.0Hz to the upfield compared with that in C2H4 The upfield shift in C2 H2D2 was about twice as large as that in C2H3D The theoretical results are in good agreement with experimental ones.