Effect of Molecular Symmetry on the Spectra and Dynamics of the Intramolecular Charge Transfer (ICT) state of peridinin.
Effect of Molecular Symmetry on the Spectra and Dynamics of the Intramolecular Charge Transfer (ICT) state of peridinin.
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DOI：
10.1021/jp305804q
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发表时间：
2012-09-06
影响因子：
3.3
通讯作者：
Frank, Harry A.
中科院分区：
文献类型：
--
作者：
Enriquez, Miriam M.;Hananoki, Shohei;Hasegawa, Shinji;Kajikawa, Takayuki;Katsumura, Shigeo;Wagner, Nicole L.;Birge, Robert R.;Frank, Harry A.
利用稳态吸收光谱、荧光光谱和超快时间分辨光谱研究了两种不同合成的多甲苷类似物的激发态的光谱性质和动力学随溶剂极性的变化。类似物被表示为S-1-和S-2-多甲素，并且在内酯环及其相关羰基的位置上不同于天然存在的多甲素，已知对于类胡萝卜素的S1状态的寿命的溶剂依赖性的观察是必需的。相对于多甲藻素，S-1-和S-2-多甲藻素的内酯环分别向共轭碳-碳双键的π电子系统的中心多两个和四个碳。实验结果表明，随着溶剂极性的增加，分子的稳态光谱变宽，S-1-peridinin的最低激发态寿命从~155 ps变化到~17 ps，这与报道的对peridinin的影响程度相似。溶剂诱导的S-2-多甲苷素的最低激发态寿命的变化要小得多，并且随着溶剂极性的增加仅从~90 ps变化到~67 ps。这些结果被解释在分子内电荷转移（ICT）的状态，很容易形成的多甲苷和S-1-多甲苷，但不是在S-2-多甲苷。量子力学计算揭示了ICT状态形成所需的关键因素，以及这些分子和其他含羰基类胡萝卜素和多烯的光谱和动力学上的相关溶剂调制效应。这些因素是基态和激发态偶极矩的大小和方向，它们必须适合于产生最低的两个激发单重态的充分混合。
The spectroscopic properties and dynamics of the excited states of two different synthetic analogues of peridinin were investigated as a function of solvent polarity using steady-state absorption, fluorescence, and ultrafast time-resolved optical spectroscopy. The analogues are denoted S-1- and S-2-peridinin and differ from naturally-occurring peridinin in the location of the lactone ring and its associated carbonyl group, known to be obligatory for the observation of a solvent dependence of the lifetime of the S1 state of carotenoids. Relative to peridinin, S-1- and S-2-peridinin have their lactone rings two and four carbons more toward the center of the π-electron system of conjugated carbon-carbon double bonds, respectively. The present experimental results show that as the polarity of the solvent increases, the steady-state spectra of the molecules broaden, and the lowest excited state lifetime of S-1-peridinin changes from ~155 ps to ~17 ps which is similar to the magnitude of the effect reported for peridinin. The solvent-induced change in the lowest excited state lifetime of S-2-peridinin is much smaller and changes only from ~90 ps to ~67 ps as the solvent polarity is increased. These results are interpreted in terms of an intramolecular charge transfer (ICT) state that is formed readily in peridinin and S-1-peridinin, but not in S-2-peridinin. Quantum mechanical computations reveal the critical factors required for the formation of the ICT state and the associated solvent-modulated effects on the spectra and dynamics of these molecules and other carbonyl-containing carotenoids and polyenes. The factors are the magnitude and orientation of the ground and excited state dipole moments which must be suitable to generate sufficient mixing of the lowest two excited singlet states.
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线性多烯的低裂隙激发态的能量。
DOI：
10.1021/jp8060202
发表时间：
2008-12-11
期刊：
The journal of physical chemistry. A
影响因子：
--
作者：
Christensen RL;Galinato MG;Chu EF;Howard JN;Broene RD;Frank HA
通讯作者：
Frank HA
影响因子：
3.3
作者：
Bautista, JA;Connors, RE;Frank, HA
通讯作者：
Frank, HA
影响因子：
3.3
作者：
Herek, JL;Wendling, M;Pullerits, T
通讯作者：
Pullerits, T
影响因子：
4.4
作者：
Ishida, M;Toyota, K;Nakatsuji, H
通讯作者：
Nakatsuji, H
影响因子：
4.4
作者：
KOCH, H;KOBAYASHI, R;JORGENSEN, P
通讯作者：
JORGENSEN, P