Structure and reaction dynamics in gas phase solute-solvent heteroclusters

气相溶质-溶剂异质团簇的结构和反应动力学

基本信息

批准号：
10206209
负责人：
HONMA Kenji
金额：
$ 13.89万
依托单位：
Himeji Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10206209/
关键词：
Condenced Phase Charge transfer reaction Clusters Protein folding Electrospray 電荷移動

项目摘要

We have carried out the following two projects and obtained some interesting results.(1)Dynamics of the electronically excited state of 9,9'-bianthryl(BA) was studied in gas-phase clusters with acetonitrile (ACN), BA-(ACN)_n(n=1-5). The mass-selected two-color resonance-enhanced multiphoton ionization (REMPI) spectra were measured to determine the absorption band for the cluster of BA with the specific number of the acetonitrile molecules. The dispersed fluorescence (DF) spectra and lifetimes were measured for these absorption bands to study the dynamics of the excited state of BA in the clusters, BA-(ACN)_n. For all clusters studied, the DF spectra were broad and largely red shifted compared with that of unclustered BA. The fluorescence lifetimes of BA in the clusters were considerably longer than that of unclustered BA. These results suggested that the photoexcited state of BA in the clusters change to the polar excited state which is analogous to the twisted intramolecular charge tr … More ansfer (TICT) state of BA in the acetonitrile solution. Stokes shift and lifetime of the BA-(ACN)_1 suggested that the charge-transfer reaction becomes possible by adding one acetonitrile. However, these two properties of the larger clusters did not show monotonic change toward those of BA in acetonitrile solution. These results implied that the structure and dynamics of the clusters play some important roles in the charge-transfer reaction.(2)The laser-induced fluorescence technique is applied to electrosprayed cytochrome c (cyt-c). While no fluorescence was observed for the electrospray of the solution of neutral pH, the fluorescence ascribed to the tryptophane residue was observed for the spray of the acidified solution by acetic acid. The relative intensity of the fluorescence from the acidified cyt-c is observed to increase with the distance from the end of the spray needle. This result indicates that the tryptophane residue becomes more fluorescent by the loss of solvent molecules in the electrospray. It is suggested that the highly charged cyt-c ions which preserve the nonfluorescent compact forms in solution make a conformational change by the loss of solvent in the electrospray and become fluorescent. Less

我们已经进行了以下两个项目，并获得了一些有趣的结果。（1）用乙腈（ACN），ba-（acn）_n（n = 1-5）在气相簇中进行了9,9'-二甲苯（BA）的电子激发态的动力学。测量质量选择的两色谐振增强多光子离子化（REMPI）光谱，以确定Ba簇的抽象带，并具有特定的乙腈分子数。测量了这些抽象带的分散荧光（DF）光谱和寿命，以研究簇中BA-（ACN）_N中BA激发态的动力学。对于所有研究组，与未簇的BA相比，DF光谱宽阔，并且在很大程度上变化了。认为簇中BA的荧光寿命比未簇的BA长。这些结果表明，簇中的光激发ba状态变为极性激发态，该状态类似于乙腈溶液中扭曲的分子内电荷TR…更多答案（TICT）Ba的状态。 BA-（ACN）_1的Stokes偏移和寿命表明，通过添加一个乙腈来实现电荷转移反应。但是，较大簇的这两种特性并未显示出对乙腈溶液中BA的单调变化。这些结果表明，簇的结构和动力学在电荷转移反应中起了一些重要作用。（2）激光诱导的荧光技术应用于电剥落的细胞色素C（CYTT-C）。尽管未观察到中性pH溶液的电喷雾的荧光，但观察到分配给色氨酸残基的荧光通过乙酸喷雾酸化溶液。观察到来自酸化的Cyt-C的荧光的相对强度随着从喷头末端的距离而增加。结果表明，由于电喷雾中溶剂分子的损失，色氨酸残基变得更加荧光。有人建议，在溶液中保留非荧光的紧凑形式的高电荷Cyt-C离子会通过电喷雾中的溶液损失并变成荧光，从而使构象变化。较少的