Study on the control of excitation and alleviation in chemiluminescence reaction on the basis bioluminescence

化学发光化合物2-甲基-6-(4-甲氧基苯基)咪唑[1，2-α]吡嗪-3(7H)-酮(MCLA)以酰胺键的形式连接到低聚环糖(环糊精)上。在pH 8.0的磷酸盐缓冲溶液中，研究了合成的环糊精结合的MCLA的氧致化学发光特性。发光效率显著依赖于结合环糊精的基团数、环糊精与MCLA之间的链长以及环糊精中的结合部位。与环麦芽糖(γ-环糊精)结合的化合物的发光效率高于环麦芽糖或环麦芽糖七糖结合的化合物。尤其是MCLA通过短链连接到γ-环糊精二级的化合物比非环糊精化合物提高了44倍。在这种情况下，激发单重态的形成效率是非环糊精化合物的23倍，并且对更大的发光效率有显著的贡献。诱导圆二色谱表明，γ-环糊精的第二侧入口较宽，短链使发光发色团与环糊精具有较强的分子内亲和力。

Chemiluminescence compound 2-methyl-6-(4-methoxyphenyl)imidazo[1,2 - α]pyrazin-3(7H)-one (MCLA) was attached to cyclomaltooligosaccharides (cyclodextrins) by the formation of an amide bond. The properties of oxygen-induced chemiluminescence of the synthesized cyclodextrin-bound MCLA were investigated in pH 8.0 aqueous phosphate buffer. The light-emitting efficiency was remarkably dependent n the kibnd of bounhd cyclodextrin, chain length between the MCLA and cyclodextrin, and the binding site in cyclodextrin. The light-emitting efficiencies of cyclomaltooctaose (γ-cyclodextrin)-bound compounds were higher than that of cyclomaltohexaose or cyclomaltoheptaose-bound compounds. Especially a compound in which MCLA attached to the secondary side of γ-cyclodextrin through short chain showed an up to 44 -fold enhancement over that of a non-cyclodextrin compound. In the present case, the efficiency of excited singlet state formation was 23-fold grater than that of the non-cyclodextrin compound and significantly contributed to the grater light-emitting efficiency. Induced circular dichroism spectra indicated the wide entrance of the secondary side of γ-cyclodextrin and short chain allow strong intramolecular affinity of the light-emitting chromophore and the cycrodextrin.