CIP descriptor

Thus, because of the reversal of the CIP descriptor for the arsine upon coordination to palladium, the arsine produced by the mould was predominantly of the R configuration. The identity of the diastereomeric complexes was established by carrying out a crystal and molecular structure determination on the complex S,Rj )- + )- 27, which was obtained pure after nine recrystallizations of the less soluble component of a synthetic mixture of the two diastereomers. 

R, S CIP descriptors for the specification and description of absolute configuration, as follows ... 

The registry software also computes wherever possible a CIP descriptor for each asymmetric atom, steric double bond and chirahty axis. These descriptors are stored in the BRCT and are available for display, but are not used for the purpose of registration. They are utilised however to assist in the interpretation of CIP descriptors used during structure input. A wide variety of stereochemical descriptors may be used at input, and the registry software attempts to interpret these in terms of a graphical representation from which parity codes can be computed for the purpose of registration. The simple example in Figure 8 illustrates this situation. 

There are a number of programs which compute CIP descriptors from local descriptions of configurations. " To be practically useful, however, an algorithm must, first, implement the CIP rules as completely as possible, second, notify the user when the structure is beyond the scope of the implementation, and, third, indicate whether the application of the CIP rules is not appropriate in the case at hand. We know of no system that would fulfill all these criteria. Even the first two are rarely met. 

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