P.COSY

Expansion coefficients of the anisotropic dispersion interaction in the series of Legendre polynomials P/(cosy) were evaluated using the method of Reduced Spectra of Oscillator Forces (RSOF) by Meyer et al [6] and the relevant calculations of the dynamic fragment polarizabilities [7]... 

COSY for other Nuclides. The basic COSY experiment can be carried out for any spin-5 nucleus that is 100% abundant. In addition to H- H, the procedure thus is applicable to (F,F-C0SY) and (P,P-COSY), respectively, in organofluorine and... 

This calculation is performed here for the relaxation times T ( ) and T ( ) (the time constants of the time-dependent functions corresponding to (P,(cosi )) and (FJ(cos i )e )). The differential-difference equations for these are... 

Figure 5.14. The 3 p-3 p COSY spectrum of the PrMes cluster 5.3 with the P ID spectrum below (reproduced with permission from [5]).

In addition to the J-resolved experiments several other enhanced chemical shift correlated experiments are available for determining coupling constants. A short overview and classification is given in Table 5.8. Some experiments like the P.COSY or E.COSY experiment are explained in more detail in section 5.4.1.1. 

The E.COSY group of experiments E.COSY [5.33, 5.127, 5.128], P.E.COSY [5.34] and P.COSY [5.35] have been developed to achieve the same quality of cross peak as a DQF spectra, but with the restriction that the cross peaks relate only to those transitions involving the nucleus directly. Whilst in a DQF COSY experiment the structure of the cross peaks is related to the active and passive coupling, in a E.COSY experiments the passive couplings are suppressed. 

The E.COSY experiment uses extensive phase cycling and in an effort to reduce the long acquisition times the P.E.COSY and P.COSY techniques have been developed. However these techniques require excessive post-processing of the data and consequently only the E.COSY experiment will be illustrated in Check it 5.4.1.6. For a comprehensive review of the other techniques the reader is referred to the literature [5.34,5.35]. 

The stereochemically most favorable structure for [Rh6(CO)i4L2] is shown in Eig. 5b and, when L = P(OPh)3, is the structure adopted in the solid state and in solution. There are, however, four other isomers which are theoretically possible and there is chromatographic and spectroscopic evidence for two of these isomers when L = P(OPh)3. P COSY measurements and simulations suggest that these are the next two least sterically hindered isomers. Both of these isomers, on heating, are transformed into the thermodynamically more stable isomer shown in Pig. 5b. When L = py or NCMe, separation into individual isomers was impossible because of their rapid interconversion. ... 

In LCEs the domains are never ideally aligned, and moreover, they may exhibit a different orientational order S. Thus, a distribution function w(S,cos8,(p cosi ) is introduced. 0 and are the spherical coordinates of the domain director n in the laboratory frame XYZ with ZIIBq while i9/(,Bo), where is the LCE uniaxiality axis. Assuming that the distributions of 5 and n are uncorrelated, the cumulative H-NMR spectrum is given by ... 

P )cosy we get the additional term for the rotational energy of the diatomic molecule, i.e., we have... 

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