摘 要：强酸和强碱响应的“开-关-开”可转换新型螺吡喃已被开发出来并且应用于强pH条件下菌细胞的荧光成像。强酸下的响应与吲哚N位置上的苯甲酸和吲哚6位置上的羧基有关，羧基和苯酚羟基的离子化引起了强碱条件下的响应。本文采用含时密度泛函理论（TD-DFT）B3LYP方法在6-31G*基组水平下探讨体系的前线分子轨道、结合能、电子吸收光谱和荧光计算。计算结果表明，强酸条件下螺吡喃开环形成酸性部花菁，电子吸收光谱表明酸性部花菁的特征峰在511 nm处，吸收光的颜色为绿色，根据互补色原理，溶液变成蓝绿色；强碱性条件下螺吡喃离子化，离子化的螺吡喃在440 nm有特征峰，吸收光的颜色偏紫色，溶液颜色应为蓝绿色。传感器的变色理论计算结论与实验数据结果一致，并且荧光体系与实验结果基本相同。72512

毕业论文关键词：传感器，螺吡喃，光致变色，前线分子轨道，电子吸收光谱，密度泛函理论 

Abstract：Spiropyran sensor with a “on-off-on”switch that responds to extreme acid and alkali has been developed and applied to bacterial cell fluorescence imaging under extreme pH conditions。 Benzoic acid at the indole N-position and carboxyl group at the indole 6-position lead to the extreme acid response, while ionizations of carboxyl and phenolic hydroxyl groups contributes to the extreme alkali response。 In this paper, we study the front molecular orbital, combime energy and electron absorption spectra based on 6-31G* by using the time-dependent density functional theory (TD-DFT) to demonstrate the validity of the experiment。 As expected, it is theoretically feasible for spiropyran to form merocyanine by ring-opening reactions under the extreme acid conditions。 The electronic absorption spectrum of merocyanine is characterized by its characteristic peak at 511 nm。 The color of the absorbed light is green, according to the complementary color principle, the solution will appear red。 Besides, ionization of spiropyran at the extreme alkaline conditions shows a characteristic peak at 440 nm。 The color of the absorbed light is partial purple, the color of the solution will appear blue green。 Therefore, the theory of color change calculated in the paper was in agreement with the experimental data, and fluorescence system was generally the same as the results。

Keywords: sensor, spiropyran, photochromic, frontier molecular orbitals, electronic absorption spectra, DFT

目  录

1  前言 4

2  计算方法 4

3  结果与讨论 5

3。1  几何结构 5

3。2  前线分子轨道 6

3。3  结合能 6

3。4  紫外可见光谱 7

3。5  荧光计算 9

结  论 11

参 考 文 献 12

致  谢 13

1  前言

传感器[1]是指能感受和记录规定的被测量的并且能按照一定规律转换成可输出信号的器件或装置，它早已渗透到极其广泛的领域，可以毫不夸张地说，从茫茫太空，浩瀚的海洋，到各种复杂的工程系统，几乎每一个现代化项目，都离不开各种各样的传感器。传感器包含很多类，主要有电感、光电、声波、水位、压力、电流、温度、pH等。pH值作为一种重要的参数在化学、生物及医药工程等领域起着关键性地作用。因此pH传感器[2]应运而生，并且在环境检测、生物检验、医药检验、食品监控以及文物鉴定等方面有着广泛地应用。