Bijvoet, Johannes

In 1951, Johannes Martin Bijvoet used such differences in intensity, resulting from anomalous scattering by an atom in a noncentrosymmetric crystal, to determine the chirality (absolute configuration) of the tartrate ion. Details of this method, which has been used extensively for finding the absolute configurations of natural products and for determining macromolecular structures, are given in Chapter 14. 

When crystals are noncentrosymmetric, the situation becomes more complicated because there are two possible phases angles that are derived for each reflection for data from one isomorphous pair. Therefore, in order to derive the phase angle, more than one isomorphous pair is required. This problem was first tackled by Johannes M. Bijvoet, Cornells Bokhoven and Jean C. Schoone, who solved the noncentrosymmetric isomorphous structures of strychnine sulfate and selenate. ... 

Other representations of 48 and 49 are also shown, including the normal line notation used with other molecules in this book. Fischer assigned (d) to the (+) enantiomer (which happens to be dextrorotatory), but this was an arbitrary choice (a guess that is properly called an assiunption). Remember from Chapter 9 (Section 9.2) that (+) and (-) refer to specific rotation, which is a physical property, whereas d and 1 are names. In 1851, Johannes Martin Bijvoet (the Netherlands 1892-1980) showed by x-ray analysis that Fischer s assignments were correct. 

Professor Johannes M. Bijvoet (1892-1980), University of Utrecht, The Netherlands. 

In 1951, the Dutch crystallographer Johannes Bijvoet established the absolute configurations of these compounds by the X-ray diffraction analysis of a salt of tartaric acid, which had been correlated by chemical means with Fischer s sugars and, in turn, glycCTaldehyde. As Bijvoet states in his papa- (abbreviated), The result is that Emil Fischo- s convention. . . appears to answer the reality. Lucky guess ... 

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