s13.m36.o3 Mogul: Rapid Retrieval of Molecular Geometry Information From a Crystallographic Database

The Cambridge Structural Database (CSD) currently contains over 310,000 structure determinations for small molecule organic and organometallic compounds, and thus is a good source of information on molecular geometries and conformational preferences. The program Mogul (Molecular Geometry Library) has been developed by the CCDC to provide rapid access to this information with full statistics. To retrieve information on a bond length, valence angle or acyclic torsion, the user inputs a molecule of interest intoMogul and selects the geometric feature to be investigated. The molecular environment of the selected fragment is used to generate atomand bond-based "keys", which are then used to retrieve all relevant CSD hits. The use of a search tree optimises search speeds without the need for graph-based atom-by-atom matching typically used by other retrieval programs such as ConQuest [1]. Key statistics and histograms are derived and displayed along with an indication of how well the geometry of the feature in the input molecule matches observed geometries in the CSD. Mogul searches can be run automatically via an instructions file with results written to an output file, allowing easy integration with other programs. Mogul has already been integrated with CRYSTALS [2] in this way to allow validation of molecular geometries of newly refined crystal structures; a similar use is envisaged with DASH [3], which aids the solving of structures from powder diffraction data. Other potential applications will be discussed.