Is it possible to specify stereochemical configuration when constructing a query using the sketcher?
The 2D representations of structures in the database only contain information concerning connectivity of atoms, no stereochemical information is given in these diagrams. As a result, it is not possible to sketch a query in terms of 'up and down' or 'dark filled/dashed line' bond representation. Absolute stereochemistry is included in the CSD but only when the information is provided by the author in the original publication. When included in the database absolute configuration must have been determined using one of the following methods:
- Anomalous dispersion (Bijvoet pairs, Friedel pairs, Hamilton test, R-factor ratio, eta refinement or Rogers' eta parameter; the parameter is not recorded)
- Internal comparison
- Refinement of the Flack parameter (no value of the parameter or reference to use of the Flack parameter is recorded)
When present, information relating to stereochemistry is given within the compound name under the Chemical tab. In addition, if the absolute configuration of the structure has been determined, then the entry will also include the phrase absolute configuration under the chemical tab.