Correlation diagram technique

Predictions can be made about the suitability of different system trajectories on the basis of orbital symmetry conservation rules (207). The most suitable trajectory is an approximation to the reaction path of the reaction under study. The rules can also yield information about the possible structure of the activated complex. The correlation diagram technique has been improved in a series of books by Epiotis et al. (214-216). The method is based on self-consistent field-configuration interaction or valence bond (SCF-CI or VB) (including ionic structures) wave functions. Applications on reactions in the ground states as well as in the excited electronic states are impressive however, the price to be paid for the predictions seems to be rather high. 

The techniques which can be used for the construction of orbital correlation diagrams are well known 2,5,8,20) an(j neeq not be reviewed... 

The energy of the - dx -y transition is most sensitive to the presence of axial ligands which interact directly with the dz orbital on the cop-per(II) ion. Such a correlation diagram has been established using the technique of polarised single-crystal electronic spectroscopy 20) which not only resolves the component bands of the three possible transitions of Fig. 8 as in Fig. 9, but under favourable circumstances may allow the... 

Application of continuous wave techniques and line shape analysis to wide-line n.m.r. spectra Cf D-xylose, D-mannose, D-glucose, D-fructose, and D-sorbose suggests that the lattice is effectively rigid in all except possibly D-fructose. Previously published C n.m.r. data for arabinosides and ribosides have been tabulated with correlation diagrams constructed in such a way that the data on new compounds can be used to assign the anomerlc configurations and ring size. Measurements of self-diffusion coefficients of carbo-... 

This original intuitive formulation is not, however, completely satisfactory. This is due to the fact that the above simple approach is not completely general, since its applicability is restricted only to electrocyclic and sigmatropic reactions but not to cycloadditions. For that reason the studies speared early after the formulation of Woodward-Hoffinann rules, attempting to place these rules on a more sound theoretical basis. The most important of these alternative approaches is the technique of the so-called correlation diagrams [16,23-25]. 

The continuing progress of the theory of pericyclic reactions made it, however, still more apparent that irrespective of its nondisputable conceptual contribution, neither is the technique of the correlation diagrams able to explain all types of reactions [29,30]. The example of the situation where this technique encounters with certain difficulties are, e.g., the valence isomerizations. These difficulties are due to specific form of the correlation diagrams where both the HOMO and the LUMO are frequently of the same symmetry so that it is not possible to decide on the basis of symmetry only, which of the possible alternative correlations are in a given case correct. 

Similarly as with all theoretical models, ihcluding the technique of correlation diagrams, the first step of the analysis is the maximal simplification of the... 

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