E. Kavlakoğlu, A. Yaman, F. Bayrakçeken
Oct 1, 1999
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Journal
Analytical Sciences
Abstract
cal properties of the molecule 5H-dibenzo[a,d]cyclohepten-5-one, which corresponds, at least in its structure, to 5H-dibenzo[a,d ]cyclohepten-5-ol, 5Hdibenzo[a,d]cycloheptenes, and the cis-isomer of stilbene. Only a few previous studies of 5Hdibenzo[a,d]cycloheptene have been carried out.1–4 Also, the crystal structure of its derivative, 5Hdibenzo[a,d]cyclohepten-5-ol, has been studied.5,6 A study of the crystal structure of the title compound showed that the benzyl groups accepts hydrogen bonds from a hydroxy and an ethynyl group, one to each face of the ring. The bond donated by the hydroxy group has an unusual geometry, and is directed almost linearly at a “C” atom with “H–C”=2.36 Å. All operations were performed in an atmosphere of dry argon using vacuum techniques. NMR and IR spectra were recorded and crystallographic data were characterized.7,10 All of the analytical data support the adsorption mechanism and corroborate the theoretical predictions that (4n+2)πelectron aromaticity can be induced in 5Hdibenzo[a,d]cyclohepten-5-one. A comparison of the sorption of Dibenzotropone and 5H-dibenzo[a,d]cyclohepten-5-one by montmorillonite clearly demonstrates the importance of π interactions in the interlamellar space. π interactions between adsorbed cationic dyes and the oxygen planes of montmorillonite have been reported.7,11 A photoreaction, the photoketonization of 5H-dibenzo[a,d]cyclohepten-5-one in aqueous solution, was reported, the mechanism of which was believed to involve an initial ionization of the C–H proton at the 5-position in S1, to generate a dibenzosuberenyl carbanion intermediate.12 The work reported here was undertaken with the aim of determining the values of a number of photophysical parameters which are of significance to the photochemistry of the excited singlet and triplet states. Experimental