[Phenomena of supramolecular assembly fluid room temperature phosphorescence (II)--effects of alcohols on room temperature phosphorescence of cyclodextrin/4-iodo-4'-ethyl-biphenyl/bromocyclohexane system].

Beta-cyclodextrin( beta/-CD)can induce 4-iodo-4'-ethyl-biphenyl(IEBP)to emit room temperature phosphorescence(RTP) in the presence of bromocyclohexane (BCH). If butyl alcohol (BuOH) is presented as a fourth component at the same time, RTP intensity of the system is enhanced obviously. Effects of different alcohols, CDs and derivatives of beta-CD on RTP emission of the system are studied. The results show that a ternary host-guest inclusion complex is formed among beta-CD, IEBP and BCH, but the alcohol hydroxyl bonds to the rim of the CD cavities by hydrogen-bonding and the alkyl end of alcohol flips over the two tops of the CD due to hydrophobic interaction force. Accordingly, the alcohol acts as a lid for CD cup, thereby shielding IEBP from oxygen and decreasing the collision quenching of oxygen, and decreasing the micro polarity of the CD cavity and the formation constant of ternary inclusion complex increases. As a result, the RTP of the system is enhanced. As far as we can see that the system studied is a typical supramolecular assembly one and the BuOH acts as a molecular regulation for RTP emitting.