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Free keywords:
Molecular sieves;
guest-host;
DMABN;
optical properties;
fluorescence
Abstract:
The fluorescence of p-N,N-dimethylaminobenzonitrile (DMABN) in molecular sieve pores of ZSM-5 shows two maxima. However, these maxima are located at shorter wavelengths compared with DMABN in solutions. In addition, the polarizations of both bands are different compared with the fluorescence polarizations in solutions. In molecular sieve pores, the high energy emission is positively, the low energy emission is only weakly polarized. Therefore, the mechanism explaining the two maxima of the fluorescence cannot be the usual twisted intramolecular charge transfer as in solutions. The proposed explanation assumes that the sorbed DMABN molecules are not able to be twisted in the narrow molecular sieve channels.
