We describe here an application of the practical, simple, and reliable approach for the determination of the absolute configuration of sterically demanding tert/tert vic-diols. According to this method, it is only necessary to mix dimolybdenum tetraacteate and a chiral diol in DMSO and record the CD spectra in the 250-650 nm spectral range. From the sign of the CD bands occurring at around 310, 350, and 400 nm, it is possible to establish the chirality of the diol unit expressed by the sign of the O-C-C-O torsion angle. Because the preferred conformation of the diol in the formed complex is known, we are able to determine the absolute configuration of the carbon atoms in the diol subunit even in flexible tert/tert vic-diols.

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We propose a standard operating procedure for the estimation of the amount of 2212 and 2201 phases in a 2223 PBSCCO HTSC powder, based on one to two observed x-ray powder diffraction intensities for each phase. The quantitative phase analysis takes into account the effects of preferred orientation, structure factor magnitude and particle absorption contrast. The procedure is derived from Rietveld analysis of the full diffractogram.