Mostafa Gamal A E, Mahajumi Abu Syed, AlRabiah Haitham, Kadi Adnan A, Lu Yang, Rahman A F M Motiur
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia.
Micro-Analytical Laboratory, Department of Applied Organic Chemistry, National Research Center, Dokki, 12622, Cairo, Egypt.
J Fluoresc. 2021 Sep;31(5):1489-1502. doi: 10.1007/s10895-021-02789-y. Epub 2021 Jul 21.
Fluorescein (1), a known fluorescent tracer in microscopy with high photophysical properties, was esterified to have fluorescein ethyl ester (2) and O-ethyl-fluorescein ethyl ester (3) in excellent yields. All of them were investigated for the photophysical and electrochemical properties as potential organic semiconductor materials. Absorptions and emission spectra were taken in various solvents, compound 2 showed emission maxima at λ = 545 and compound 3 showed λ = 550 nm. Optical band gap energy (E) was calculated for 1-3 and the values were found in between 2.34 - 2.39 eV. Possibility of shifting emission maxima was studied in various pH (5-9) buffers, and finally the thermal stability was examined using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Increasing of conjugation system of 2 and 3 were studied by HOMO and LUMO distributions of 1-3. Experimental results showed that compounds 2 and 3 have excellent photophysical and electrochemical properties hence can be used as excellent organic semiconductor materials.
荧光素（1）是显微镜学中一种已知的具有高光物理性质的荧光示踪剂，它被酯化以高产率得到荧光素乙酯（2）和O - 乙基 - 荧光素乙酯（3）。对所有这些化合物作为潜在有机半导体材料的光物理和电化学性质进行了研究。在各种溶剂中获取吸收光谱和发射光谱，化合物2在λ = 545处显示发射最大值，化合物3在λ = 550 nm处显示发射最大值。计算了1 - 3的光学带隙能量（E），其值在2.34 - 2.39 eV之间。研究了在各种pH（5 - 9）缓冲液中发射最大值发生偏移的可能性，最后使用差示扫描量热法（DSC）和热重分析（TGA）检测了热稳定性。通过1 - 3的最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）分布研究了2和3共轭体系的增加情况。实验结果表明，化合物2和3具有优异的光物理和电化学性质，因此可作为优异的有机半导体材料。
