Hashimoto Yamato, Takeda Toyoho, Ogasawara Shin, Tamiaki Hitoshi
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Photochem Photobiol Sci. 2024 Dec;23(12):2227-2236. doi: 10.1007/s43630-024-00662-y. Epub 2024 Nov 27.
Zinc methyl 13,13-disubstituted 3-hydroxymethyl-pyropheophorbides-a were prepared as models of bacteriochlorophyll-d, which self-aggregated in the main light-harvesting antenna (chlorosome) of photosynthetic green bacteria. The synthetic zinc 3-hydroxy-13-oxo-chlorins possessing methyl and methoxycarbonyl groups at the 13-position could not self-aggregate in an aqueous Triton X-100 solution. However, another model compound bearing an ethane-1,2-diyl group at the 13-position did self-aggregate under the same conditions to give red-shifted and broadened Qy and Soret absorption bands. The spiro-cyclopropane condensation slightly suppressed the chlorosome-like self-aggregation due to an increase in the steric hindrance around the 13-carbonyl group. The red-shifted and broadened values of these bands by the self-aggregation were dependent on the 13-substituents. The 13-substitution substantially controlled the aqueous J-aggregation.
制备了13,13 - 二取代的3 - 羟甲基焦脱镁叶绿酸 - a的锌甲基化物作为细菌叶绿素 - d的模型，其在光合绿色细菌的主要捕光天线（叶绿体）中会发生自聚集。在13位带有甲基和甲氧基羰基的合成锌3 - 羟基 - 13 - 氧代二氢卟吩在Triton X - 100水溶液中不会发生自聚集。然而，另一种在13位带有乙烷 - 1,2 - 二基的模型化合物在相同条件下确实发生了自聚集，从而产生了红移且变宽的Qy和Soret吸收带。螺环丙烷缩合由于13 - 羰基周围空间位阻的增加而略微抑制了类似叶绿体的自聚集。这些带因自聚集而产生的红移和变宽值取决于13 - 取代基。13 - 取代对水性J - 聚集有实质性的控制作用。
