Molecular Packing and Solid-State Fluorescence of Alkoxy-Cyano Substituted Diphenylbutadienes: Structure of the Luminescent Aggregates

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• 作者：Riju Davis ; N. S. Saleesh Kumar ; Shibu Abraham ; C. H. Suresh ; Nigam P. Rath ; Nobuyuki Tamaoki ; Suresh Das
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：February 14, 2008
• 年：2008
• 卷：112
• 期：6
• 页码：2137 - 2146
• 全文大小：503K
• 年卷期：v.112,no.6(February 14, 2008)
• ISSN：1932-7455

文摘

A detailed study on the photophysical properties of a series of alkoxy substituted diphenylbutadienes in solutionand in the solid state providing a molecular level understanding of the factors controlling their solid-stateluminescence behavior is reported. Our studies provide clear evidence for exciton splitting in the solid stateresulting in red-shifted emission for this class of materials. The role of the number of alkoxy substituents andthe alkyl chain length in controlling the nature of the molecular packing and consequently their fluorescenceproperties has been elucidated. Whereas in the di- and tri-alkoxy substituted derivatives, the solid-statefluorescence was independent of the length of the alkyl chains, in the monoalkoxy substituted derivatives,increasing the length of the alkyl chain resulted in a visual change in fluorescence from green to blue. On thebasis of the analysis of the molecular packing in the single crystals, this difference could be attributed tofluorescence arising from aggregates with an edge-to-face alignment in the molecules possessing short alkylchains (methyl and butyl) to monomer fluorescence in the long alkyl chain containing derivatives.