Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, North-13 West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
Chemistry. 2016 Jul 11;22(29):9996-10001. doi: 10.1002/chem.201601882. Epub 2016 Jun 15.
The enhancement of the light absorption ability of synthetic chlorophyll derivatives is demonstrated. Chlorophyll derivatives directly conjugated with a difluoroboron 1,3-diketonate group at the C3 position were synthesized from methyl pyropheophorbide-d through Barbier acylmethylation of the C3-formyl moiety, oxidation of the C3-carbinol, and difluoroboron complexation of the diketonate. Electronic absorption spectra in a diluted solution showed that the synthetic conjugates gave an absorption band at λ=400-500 nm, with a Qy band shifted to a longer wavelength of λ≈700 nm. DFT calculations demonstrated that the absorption bands and redshifts were ascribable to the coupling of the LUMO of chlorin with that of the difluoroboron diketonate moiety. The introduction of a pyrenyl group at the C3(3) -position of the conjugate afforded an additional charge-transfer band over λ=500 nm, producing a pigment that bridged the green gap in standard chlorophylls.
展示了合成叶绿素衍生物光吸收能力的增强。通过 C3-甲酰基部分的 Barbier 酰基化、C3-仲醇的氧化和二酮的二氟化硼络合，从甲基吡咯并叶啉-d 直接合成了在 C3 位与二氟硼 1,3-二酮基团直接共轭的叶绿素衍生物。在稀溶液中的电子吸收光谱表明，合成的轭合物在 λ=400-500nm 处给出吸收带，Qy 带移至较长的 λ≈700nm。DFT 计算表明，吸收带和红移归因于叶绿素的 LUMO 与二氟硼二酮酯部分的耦合。在共轭物的 C3(3)-位引入一个并五苯基，在 λ=500nm 以上产生了额外的电荷转移带，产生了一种颜料，它桥接了标准叶绿素的绿色间隙。
