STUDY OF BODIPY DERIVATIVE COMPOUNDS AS PH INDICATORS AND THEIR APPLICATION IN CHEMISTRY EXPERIMENT MODULE

• Main Author: Hanifah Pratiwi, Ghalda
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/87533
• Institution: Institut Teknologi Bandung

Acidity or pH plays a crucial role in life, such as affecting the taste of fruits and the function of household products. Common pH indicators have limitations, including less accurate readings, susceptibility to contamination by other substances, and difficulty in measuring low-concentration samples. Fluorescence-based pH measurement techniques are advantageous because of their non-destructive nature, high sensitivity and specificity, ease of use, and require only a small amount of sample. BODIPY, also known as boron-dipyrromethene, is a fluorescent compound that is thermally and photochemically stable, exhibits high fluorescence quantum yields, and can be easily synthesized and modified. Therefore, this research aimed to synthesize phenolic BODIPY compounds (3-allyl-4-hydroxyphenyl BODIPY 3c) and phenyl BODIPY compounds with electron-donating substituents (4 fluorophenyl BODIPY 3a and 4-allyloxyphenyl BODIPY 3b), investigate the properties of these BODIPY compounds (3a–3c), along with vanillin BODIPY (3d) in relation to pH levels using UV-Vis and fluorescence spectroscopy techniques, and develop a chemistry experiment module for acid-base fluorescence concept. BODIPY 3a–3c were successfully synthesized with yields ranging from 21.7% to 91.4%. UV-Vis spectroscopy showed that BODIPY compounds 3a and 3b were stable at pH 1–11.9, whereas BODIPY compounds 3c and 3d formed hemi-quinone species at pH 10–11.9. Fluorescence spectroscopy revealed a slight decrease in the fluorescence intensity of BODIPY compounds 3a and 3b under both acidic and basic conditions. In contrast, BODIPY compounds 3c and 3d showed increased intensity under acidic conditions but decreased intensity under basic conditions. The fluorescence quantum yields of BODIPY compounds 3a–3d in CH2Cl2 were in the range of 0.06–0.15 and CH3CN 0.002–0.05 with rhodamine B as a reference. These results indicated that phenolic BODIPY compounds have potential as fluorescence-based pH indicators. Additionally, the chemical experiment module was successfully developed as a supplementary resource for teaching the fluorescence acid-base concept at the high school level.