Rajapakse R M Gamini, Horrocks Benjamin R, Malikaramage A U, Gunarathna H M N P, Egodawele M G S A M E W D D K, Jayasinghe J M Susanthi, Ranatunga Udayana, Herath W H M R N K, Sandakelum Lahiru, Wylie Shane, Abewardana P G P R, Seneviratne V N, Perera L L K, Velauthapillai D
Department of Chemistry, Faculty of Science, University of Peradeniya Peradeniya 20400 Sri Lanka
School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 4LB UK
RSC Adv. 2023 Jun 7;13(25):17062-17073. doi: 10.1039/d3ra01769a. eCollection 2023 Jun 5.
Berberine was extracted from (tree turmeric) and purified by column chromatography. The UV-Vis absorption spectroscopy of berberine was studied in acetonitrile and aqueous media. TD-DFT calculations employing the B3LYP functional were found to reproduce the general features of the absorption and emission spectra correctly. The electronic transitions to the first and second excited singlet states involve a transfer of electron density from the electron donating methylenedioxy phenyl ring to the electron accepting isoquinolium moiety. An estimate of the electrochemical gap (2.64 V) was obtained from microelectrode voltammetry and good agreement was found with quantum chemical calculations using the cc-pVTZ basis set and the B3LYP, CAM-B3LYP and wB97XD functionals. The calculations indicate spin density of the radical dication is delocalised over the molecule. These basic data are useful for assessment of the synthesis of donor-acceptor polymeric materials employing oxidative polymerization or co-polymerisation of berberine.
小檗碱从（树姜黄）中提取，并通过柱色谱法纯化。研究了小檗碱在乙腈和水性介质中的紫外可见吸收光谱。发现采用B3LYP泛函的TD-DFT计算能够正确重现吸收光谱和发射光谱的一般特征。向第一和第二激发单重态的电子跃迁涉及电子密度从供电子的亚甲二氧基苯环转移到受电子的异喹啉鎓部分。通过微电极伏安法获得了电化学能隙的估计值（2.64 V），并且发现与使用cc-pVTZ基组以及B3LYP、CAM-B3LYP和wB97XD泛函的量子化学计算结果吻合良好。计算表明自由基二价阳离子的自旋密度在分子上是离域的。这些基础数据对于评估采用小檗碱的氧化聚合或共聚反应合成供体-受体聚合物材料很有用。
