Karcz Dariusz, Boroń Bożena, Matwijczuk Arkadiusz, Furso Justyna, Staroń Jakub, Ratuszna Alicja, Fiedor Leszek
Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland.
Molecules. 2014 Oct 3;19(10):15938-54. doi: 10.3390/molecules191015938.
Practical applications of photosynthesis-inspired processes depend on a thorough understanding of the structures and physiochemical features of pigment molecules such as chlorophylls and bacteriochlorophylls. Consequently, the major structural features of these pigments have been systematically examined as to how they influence the S1 state energy, lifetimes, quantum yields, and pigment photostability. In particular, the effects of the macrocyclic π-electron system, central metal ion (CMI), peripheral substituents, and pigment aggregation, on these critical parameters are discussed. The results obtained confirm that the π-electron system of the chromophore has the greatest influence on the light energy conversion capacity of porphyrinoids. Its modifications lead to changes in molecular symmetry, which determine the energy levels of frontier orbitals and hence affect the S1 state properties. In the case of bacteriochlorophylls aggregation can also strongly decrease the S1 energy. The CMI may be considered as another influential structural feature which only moderately influences the ground-state properties of bacteriochlorophylls but strongly affects the singlet excited-state. An introduction of CMIs heavier than Mg2+ significantly improves pigments' photostabilities, however, at the expense of S1 state lifetime. Modifications of the peripheral substituents may also influence the S1 energy, and pigments' redox potentials, which in turn influence their photostability.
受光合作用启发的过程的实际应用取决于对叶绿素和细菌叶绿素等色素分子的结构和物理化学特征的透彻理解。因此，人们系统地研究了这些色素的主要结构特征，以了解它们如何影响S1态能量、寿命、量子产率和色素光稳定性。特别讨论了大环π电子体系、中心金属离子（CMI）、外围取代基和色素聚集对这些关键参数的影响。所得结果证实，发色团的π电子体系对卟啉类化合物的光能转换能力影响最大。其修饰导致分子对称性变化，这决定了前沿轨道的能级，从而影响S1态性质。就细菌叶绿素而言，聚集也会强烈降低S1能量。CMI可被视为另一个有影响的结构特征，它仅适度影响细菌叶绿素的基态性质，但强烈影响单重激发态。引入比Mg2+重的CMI可显著提高色素的光稳定性，然而，这是以牺牲S1态寿命为代价的。外围取代基的修饰也可能影响S1能量和色素的氧化还原电位，进而影响它们的光稳定性。
