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）咪唑并[1，2- α]吡嗪-3（7 H）-酮（MCLA）通过酰胺键连接到环状麦芽糖寡糖（环糊精）上。在pH8.0的磷酸盐缓冲溶液中研究了环糊精结合的MCLA的氧诱导化学发光性质。结果表明，环糊精的种类、环糊精与MCLA之间的链长以及环糊精的结合位置对MCLA的发光效率有显著的影响。与环麦芽八糖（γ-环糊精）结合的化合物的发光效率高于与环麦芽六糖或环麦芽七糖结合的化合物。特别是其中MCLA通过短链连接到γ-环糊精的次级侧的化合物显示出比非环糊精化合物高达44倍的增强。在这种情况下，激发单重态形成的效率比非环糊精化合物的激发单重态形成的效率高23倍，并且显著地有助于更高的发光效率。诱导圆二色光谱表明，γ-环糊精的二次侧较宽的入口和较短的链段使得发光生色团与环糊精分子内具有较强的亲和力。

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.