- Enhance the fluorescence and singlet oxygen generation ability of BODIPY: Modification on the meso-phenyl unit with electron withdrawing groups
-
Herein, meso-R-carboxyphenyl substituted BODIPY compounds were synthesized and characterized (R = CH3, COOH, NO2, H and Br4). The fluorescence, excited triplet state and singlet oxygen formation properties for these compounds were measured in nonpolar and polar solvents by UV–vis absorption, steady-state and time-resolved fluorescence methods, as well as laser flash photolysis technique. These BODIPYs exhibit very different fluorescence quantum yield and lifetime value, as well as singlet oxygen formation capability in polar solvents. In contrast, these compounds show very similar spectral shape and position, emit bright green fluorescence in non polar solvents. The introduction of an ortho-COOH on the benzene unit leads to a 20-fold increase in the fluorescence quantum yield. The further introduction of an electron withdrawing NO2 or COOH on the phenyl makes the BODIPY dye show much higher capability to generate singlet oxygen (up to 5-fold increase) and causes a sharp decrease in both fluorescence quantum yield and lifetime value. The increase in solvent polarity enhances singlet oxygen generation and intramolecular fluorescence quenching. The results are explained by the presence of intramolecular photoinduced electron/charge transfer from BODIPY core to the carboxyphenyl moiety.
- Zhang, Xian-Fu,Zhang, Yakui,Xu, Baomin
-
-
Read Online
- Method for synthesizing 4-fluorophthalic acid
-
The invention discloses a method for synthesizing 4-fluorophthalic acid. The method comprises the following steps: dissolving a raw material 4-nitrophthalic acid in thionyl chloride, performing chloroformylation, performing fluorodenitration by using a dr
- -
-
Paragraph 0025-0028; 0036-0039
(2018/09/28)
-
- Water-induced fluorescence quenching of mono- and dicyanoanilines
-
Photophysical properties of monocyano- (2-, 3-, and 4-cyano) and dicyano- (3,4-, 3,5-, 2,3-, 2,4-, 2,5-, and 2,6-dicyano) anilines are investigated by fluorescence measurements. All the monocyanoanilines are virtually nonfluorescent in water (quantum yield 0.01); however, in nonaqueous solvents (cyclohexane, acetonitrile and ethanol), the fluorescence quantum yield is enhanced substantially. In contrast, dicyanoanilines investigated are highly fluorescent both in aqueous and nonaqueous environments. The photophysical data and MO calculations suggest that conformational changes in the amino group and variation of hydrogen-bonding interactions between the solute and solvent water upon electronic excitation are responsible for the water quenching in the monocyanoanilines.
- Oshima, Juro,Yoshihara, Toshitada,Tobita, Seiji
-
p. 306 - 311
(2008/02/13)
-
- Aspects of Tautomerism: Part X - Neighbouring Group Effects on the Structure and Reactivity Patterns of Acid Chlorides
-
The influence of neighbouring groups on the structure and reactivity patterns of over one hundred acid chlorides derived from γ- and δ-keto acids, 1,2- and 1,3-dicarboxylic acid half-esters and diacid chlorides have been examined.Contrary to reports in the literature, text books and monographs, evidence has been obtained for the non-existence of tautomerism between the isomeric pairs of either acid chlorides or half-ester acid chlorides.ce.
- Bhatt, M. Vivekananda,El Ashry, Shaker H.,Somayaji, Vishwanatha
-
p. 473 - 486
(2007/10/02)
-