Spectroscopic Behaviour Of 1-Methyl-4-[4-Aminostyryl] Pyridinium Iodide In CyclodexterinsAuthor(s): Samy A.El-Daly, Raafat M.Issa, Mahmoud H.Abdel Kader, El-Sayed A.El-Sherbini
The electronic absorption and emission spectra of 1-methyl-4-[4-aminostyryl] pyridinium iodide(M-NH2) were measured in cyclodexterins(CDs) of different cavity sizes. The binding constant kb of inclusion complex was found to be 67.03 M-1 for (dye-α-CD), 419.7 M-1 for(dye-β-CD) and 1134.8 M-1 for(dye-γ-CD). The fluorescence quantum yield is sensitive to diameters of cyclodextrin and was found to be 0.183, 0.129 and 0.114 in α- CD, β-CD and γ-CD, respectively. The quantum yield of the cis-trans photoisomerization was also determined in CD at pH=1.1 and was found to be Φt-c=0.62 and Φc-t=0.37 The ground state and excited state protonation constants were calculated in sodium dodecyl sulphate(SDS) and amounted to 3.95 and -10.24, respectively.