title: Synthesis and photophysical studies of oxazole rings containing compounds as electron accepting units.
abstract: A series of oxazole derivatives, 5-methyl-2-(p-methylphenyl)-4-acetyl oxazole (MMPAO), 5-methyl-2-(p-methoxyphenyl)-4-acetyl oxazole (MOPAO), 5-methyl-2-(p-N,N'-dimethylamino-phenyl)-4-acetyl oxazole (MDMAPAO) and 5-methyl-2-(p-N,N'-diphenylaminophenyl)-4-acetyl oxazole (MDPAPAO) have been synthesized and studied to compare their photophysical properties. The UV-visible absorption spectra of MDMAPAO and MDPAPAO are bathochromatically shifted as compared to that of MMPAO and MOPAO. The fluorescence emission of MDPAPAO is very sensitive to the polarity of solvents. The magnitude of change in the dipole moment was calculated using the Lippert-Mataga equation. MDPAPAO shows the highest change in the dipole moment (Δu=13.3D) than that of the other three oxazole derivatives. The spectral properties including fluorescence quantum yield and lifetime were determined in solvents with different polarities. MDPAPAO displays the highest fluorescence quantum yield and lifetime, following a bi-exponential fluorescent decay fashion. Our result demonstrates that the excited state of MDPAPAO possesses the property of intramolecular charge transfer.
authors.affiliation: School of Chemistry and Chemical Engineering, and Center of Environmental Science and Engineering Research, Shanxi University, Taiyuan 030006, PR China.
authors.forename: Caihong
authors.initials: C
authors.lastname: Zhang
authors.forename: Lifeng
authors.initials: L
authors.lastname: Li
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Wu
authors.forename: Zhixun
authors.initials: Z
authors.lastname: Liu
authors.forename: Junfen
authors.initials: J
authors.lastname: Li
authors.forename: Guomei
authors.initials: G
authors.lastname: Zhang
authors.forename: Guangming
authors.initials: G
authors.lastname: Wen
authors.forename: Shaomin
authors.initials: S
authors.lastname: Shuang
authors.forename: Chuan
authors.initials: C
authors.lastname: Dong
authors.forename: Martin M F
authors.initials: MM
authors.lastname: Choi
mesh_terms: D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry; D004583:Electrons; D010080:Oxazoles / Q000138:chemical synthesis / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001555:Benzene Derivatives; D010080:Oxazoles; D012997:Solvents