Effect of natural and modified cyclodextrins on the absorption and 2D, 3D fluorescence spectra of 7‑hydroxy‑4‑methyl coumarin (HMC) have been investigated in different buffer solutions (pHs – 1.0, 6.5 and 10.0). Both neutral and monoanion species were formed in the ground state, whereas three species such as zwitterion, neutral and monoanion in the excited state in the above mentioned pH ranges. The excited state property of HMC obviously varied with the results from the absorption data. The excited state proton transfer was observed at low pH from the hydroxyl group to carbonyl group of HMC. FT-IR, PXRD, SEM results showed the apparent variation in the natural and modified CDs with the HMC molecule. The results demonstrated that in three pH solutions, HMC forms 1:1 inclusion complex with the three CDs. Finally the proposed structures of the inclusion complexes were predicted using Semi-empirical calculations.

在不同的缓冲溶液（pH – 1.0、6.5和10.0）中，研究了天然和修饰的环糊精对7-羟基-4-甲基香豆素（HMC）的吸收以及2D，3D荧光光谱的影响。在上述pH范围内，中性和单阴离子物种均以基态形成，而在激发态的三性离子如两性离子，中性和单阴离子。HMC的激发态性质随吸收数据的结果而明显变化。在低pH下观察到HMC从羟基到羰基的激发态质子转移。FT-IR，PXRD，SEM结果表明，天然和修饰的CD随HMC分子发生明显变化。结果表明，在三种pH溶液中，HMC与三种CD形成1：1的包合物。