Nonselective relaxation rate

AMX, this is possible, because there are three nonselective relaxation-rate values for three unknown py values (pam. Pax, Pmx)- For a system in which y > 3 proton spins, this analysis cannot be unambiguously applied, because there are j(j — )/2 values of py to be determined from j measured R (ns) values. However, under favorable circumstances (see Section IV), depending on the relative disposition of the proton spins in the molecular frame, some Py values may be disregarded. This affords a good estimate of the appropriate Py values, and, hence, information about molecular geometry and conformation. 

It also is possible to determine py values from a single, nonselective experiment for more than three spin systems, by combining nonselective relaxation-rates with n.O.e. experiments. According to Noggle and Shir-mer, Eq. 5 can be solved under conditions in which, at time f = 0, spin i is observed with simultaneous saturation of spin j, resulting in the expression... 

Another separation method in using nonselective relaxation-rates is based on deuterium substitution, and utilizes the fact that the efficiency with which a nucleus contributes to the relaxation of a neighboring nucleus is proportional to the square of the magnetogyric ratio of the donor nucleus, that is, Phd/PHH = /3(yo/yn) - Because yo/yn — l/, replacement of a proton by a deuterium nucleus would be expected to contribute to the... 

The first observations on the stereochemical dependence of spin-lattice relaxation-rates of carbohydrate molecules, beginning in " 1972, provided a general survey of the nonselective relaxation-rates of the anomeric protons of monosaccharide derivatives, oligosaccharides, and some polysaccharides. 

Stereospecific dependencies of the nonselective relaxation-rates for other protons in a sugar molecule may be seen in the data for a set of 3,4,6-tri-O-acetyl-l-0-benzoyl-2-deoxy-2-bromo-D-hexopyranose derivatives (40-42), as well as other 2-halogeno derivatives. A comparison of their... 

Although nonselective relaxation-rates have been interpreted in terms of configuration and conformation, they do not readily provide information... 

Some simplified assumptions for extracting interproton relaxation-contributions from a single set of nonselective relaxation-rates have been made for a tetrachlorotetra-0-mesyl-ga/ac(o-sucrose derivative (43). By con-... 

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