Crystallographic analysis of structural effects associated with symmetrical-1,3-bridging of five-membered rings by carbonyl spacers

Article abstract of DOI:10.1016/S0040-4020(01)86829-0

The crystal and molecular structures of tricyclo[7.2.1.0^3,6]decane-2, 8-dione (4), its 4,5-benzo fused homologue (5), and tetracyclo[7.2.1.0^4,11-.0^6,10]-dodeca-2, 7-diene-5,12-dione (6) have been determined. The conformations adopted by the saturated and unsaturated five-membered rings In these molecules have been determined. The significantly different angles adopted by the carbonyl groups of the central ring in each of these diketones were also accurately measured. In order to evaluate these relationships, a companion MM2-based computational study was undertaken simultaneously and relevant comparisons are made. The range covered by this triad of molecules provides Insight into structural factors that contribute to the preferred ground-state conformations of bridged diquinane systems.