THEORETICAL-STUDY OF THE 2 TAUTOMERS OF 2-(DIPHENYLACETYL)-1,3-INDANDIONE 1-(P-(DIMETHYLAMINO)BENZALDAZINE)

Two tautomers, the keto and enol forms, of 2-(diphenylacetyl)-1,3-inda ndione 1-(p-(dimethylamino) benzaldazine) (DIPAIN) are studied. Earlie r chemometric studies of fluorescence enhancement DIPAIN has shown tha t the enhancement is associated with the ability of a compound that ha s a minimum length of 7.2 angstrom and lipophilic groups to form a mol ecular complex with DIPAIN. This paper examines molecular structure of DIPAIN and possible cavities within the molecule itself. Both forms o f DIPAIN are optimized at the Hartree-Fock level using a 3-21G basis s et. Cavity sizes of the two forms are examined. The aminobenzaldehyde ring moiety is shown to be co-planar with the C-N-N central pi system in both forms, and a cavity of approximately 7.2 angstrom is found adj acent to the central C-N-N pi system.