Suzuki, Haruka; Inoue, Ryo; Kawamorita, Soichiro; Komiya, Naruyoshi; Imada, Yasushi; Naota, Takeshi published the artcile< Highly Fluorescent Flavins: Rational Molecular Design for Quenching Protection Based on Repulsive and Attractive Control of Molecular Alignment>, Category: pyrimidines, the main research area is flavin fluorescence mol alignment quenching protection repulsive attractive control; flavins; fluorescence; hydrogen bonds; molecular design; steric hindrance.
Unprecedented intense fluorescent emission was observed for a variety of flavin compounds bearing a perpendicular cyclic imide moiety at the C7 position of an isoalloxazine platform. A series of alloxan-substituted flavins was prepared selectively by reduction of the corresponding N-aryl-2-nitro-5-alkoxyanilines with zinc dust and subsequent reaction with alloxan monohydrate in the presence of boric acid. Analogs bearing oxazolidine-2,4-dione functionality were obtained on methylation of the alloxan-substituted flavins with Me iodide and subsequent rearrangement in the presence of an inorganic base. The flavin compounds exhibit intense white-green fluorescent emission in the solution state under UV excitation at 298 K, with emission efficiencies Φ298 K greater than 0.55 in CH3CN, which are higher than the values for all reported flavin compounds under similar conditions. The highest Φ298 K value of 0.70 was obtained in CH3CN for isoalloxazine bearing C7-alloxan and N10-2,6-diisopropylphenyl groups. The temperature dependence of the emission intensities indicates that the pronounced emission properties at 298 K are attributable to the highly heat resistant properties towards emission decay with increasing temperature Mechanistic studies, including X-ray diffraction anal., revealed that the good emission properties and high heat resistance of the alloxan-substituted flavins are due to a synergetic effect of the associative nature of the C7-alloxan unit and the repulsive nature of the perpendicular bulky substituents at the C7 and N10 positions.
Chemistry – A European Journal published new progress about Crystal structure. 2244-11-3 belongs to class pyrimidines, and the molecular formula is C4H4N2O5, Category: pyrimidines.
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia