NGLC 2004-2010.National Geological Library of China All Rights Reserved. Add:29 Xueyuan Rd,Haidian District,Beijing,PRC. Mail Add: 8324 mailbox 100083 For exchange or info please contact us via email. |
NGLC 2004-2010.National Geological Library of China All Rights Reserved. Add:29 Xueyuan Rd,Haidian District,Beijing,PRC. Mail Add: 8324 mailbox 100083 For exchange or info please contact us via email. |
-cyclodextrin (CD-NA) bearing seven naphthoylchromophores forms very stable 1:1complexes with a merocyanine laser dye DCM-OH(4-(dicyanomethylene)-2-methyl-6-(p-(bis(hydroxyethyl)amino)styryl)-4H-pyran). The antenna effect, i.e. energytransfer from the naphthoyl antenna chromomophores to theencaseddye, is shown to occur with 100% efficiency. The stability of thecomplexes is very high (Ks 
105)owing to thecontribution of the naphthoate residues. The structural featuresof the complexes have been examined in detail:circular dichroism experiments confirm the expected axial orientationof DCM-OH in the cavity of CD-NA, andfluorescence anisotropy measurements together with 13C-NMRlongitudinal relaxation time measurements show thatthe complex formed between CD-NA and DCM-OH is tight. Themechanisms of homotransfer (i.e., betweennaphthoate chromophores) and heterotransfer (i.e., from naphthoatechromophores to DCM-OH included in the cavity)are discussed in light of existing theories. In both cases, themajor contribution arises more likely from Coulombicinteraction than from short-range interactions. Suchmultichromophoric cyclodextrins are good models formimicryof the antenna function in photosynthesis and show great promise asphotochemical microreactors.