title: Enhanced chemiluminescence of 6-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-3(7H)-one by attachment of a cyclomaltooligosaccharide (cyclodextrin). Attachment of cyclomaltononaose (delta-cyclodextrin).
abstract: 2-Methyl-6-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-3(7H)-one (MCLA) is an oxygen-induced chemiluminescent compound. It has been shown that the chemiluminescence can be enhanced by forming a cyclomaltooligosaccharide (cyclodextrin)-bound MCLA, and therefore, in continuation of the survey of the types of cyclodextrins, in this study, MCLA was attached to the secondary hydroxyl face of delta-cyclodextrin, which consists of nine D-glucose units. Although the oxygen-induced chemiluminescence efficiency of delta-cyclodextrin-bound MCLA in a pH 8.0 aqueous phosphate buffer was 12 times greater than that of MCLA, the efficiency was markedly lower than that of gamma-cyclodextrin-bound MCLA, which exhibited the highest chemiluminescence efficiency in the previous investigation. Although fluorescence efficiency and light-emitter formation efficiency for delta-cyclodextrin-bound MCLA were similar to those for gamma-cyclodextrin-bound MCLA, singlet-excited state formation efficiency for delta-cyclodextrin-bound MCLA was lower than that for gamma-cyclodextrin-bound MCLA. This study distinctly indicated the optimum cyclodextrin for construction of greatly luminescent cyclodextrin-bound MCLA is gamma-cyclodextrin.
authors.affiliation: Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, Mie 514-8507, Japan. teranisi@bio.mie-u.ac.jp
authors.forename: Katsunori
authors.initials: K
authors.lastname: Teranishi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nishiguchi
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Ueda
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D008163:Luminescent Measurements; D015394:Molecular Structure; D011719:Pyrazines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D003505:Cyclodextrins; D007093:Imidazoles; D011719:Pyrazines; C121706:delta-cyclodextrin; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one