title: The 1:1 host-guest complexation between cucurbit[7]uril and styryl dye.
abstract: The photophysical properties of aqueous solution of styryl dye, 4-[(E)-2-(3,4-dimethoxyphenyl)ethenyl]-1-ethylpyridinium perchlorate (dye 1), in the presence of cucurbit[7]uril (CB[7]) was studied by means of fluorescence spectroscopy methods. The production of 1:1 host-guest complexes in the range of CB[7] concentrations up to 16 μM with K = 1.0 × 10(6) M(-1) has been observed, which corresponds to appearance of the isosbestic point at 396 nm in the absorption spectra and a 5-fold increase in fluorescence intensity. The decay of fluorescence was found to fit to double-exponential functions in all cases; the calculated average fluorescence lifetime increases from 145 to 352 ps upon the addition of CB[7]. Rotational relaxation times of dye 1 solutions 119 ± 14 ps without CB[7] and 277 ± 35 ps in the presence of CB[7] have been determined by anisotropy fluorescence method. The comparison of the results of quantum-chemical calculations and experimental data confirms that in the host cavity dye 1 rotates as a whole with CB[7].
authors.affiliation: Photochemistry Center of the Russian Academy of Sciences, Moscow, Russia.
authors.forename: Denis A
authors.initials: DA
authors.lastname: Ivanov
authors.forename: Nikolai Kh
authors.initials: NKh
authors.lastname: Petrov
authors.forename: Ekaterina A
authors.initials: EA
authors.lastname: Nikitina
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Basilevsky
authors.forename: Artem I
authors.initials: AI
authors.lastname: Vedernikov
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Gromov
authors.forename: Michael V
authors.initials: MV
authors.lastname: Alfimov
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011726:Pyridinium Compounds / Q000737:chemistry*; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001952:Bridged-Ring Compounds; D005456:Fluorescent Dyes; D007093:Imidazoles; D011726:Pyridinium Compounds; C560145:4-((E)-2-(3,4-dimethoxyphenyl)ethenyl)-1-ethylpyridinium perchlorate; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils