| Popis: |
3,3′-Diacetylstilbene was produced in modest yield (26%) from a palladium(II) acetate-catalyzed coupling reaction between triethoxyvinylsilane and the triazene 1-{3-[(E)-morpholin-4-yldiazenyl]phenyl}ethanone. X-ray analysis of crystals of 3,3′-diacetylstilbene revealed a nearly planar molecule (average deviation 0.037 A) on a crystallographic inversion center. Its crystal packing was found to be composed of sheets of individual molecules of the stilbene interacting through C H···O hydrogen bonds with the sheets in turn participating in two types of weak C H···π aromatic interactions. The room-temperature absorption spectra of 3,3′-diacetylstilbene in propanenitrile and chloroform featured two π → π* transitions with maxima at approximately 250 and 300 nm. 3,3′-Diacetylstilbene was observed to be luminescent in room-temperature solution, in propanenitrile glass at 77 K, and in the solid state with maxima in the range 385–470 nm. The broadness of the emission spectra qualitatively indicated the degree that 3,3′-diacetylstilbene aggregated in solution. Quantum yields of 2 in propanenitrile and chloroform solution indicated that it had a higher fluorescence efficiency than 4,4′-diacetylstilbene. |
Full Text from ScienceDirect