Amphiphilic chlorins and bacteriochlorins in micellar environments. Molecular design, de novo synthesis, and photophysical properties
Amphiphilic chlorins and bacteriochlorins in micellar environments. Molecular design, de novo synthesis, and photophysical properties
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DOI：
10.1039/c3sc51335a
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Lindsey, Jonathan S.
中科院分区：
文献类型：
--
作者：
Aravindu, Kunche;Mass, Olga;Lindsey, Jonathan S.
两亲性四吡咯大环化合物在有机介质中的掺入对于各种基础光化学研究具有重要价值，但迄今为止的工作主要采用卟啉而不是二氢卟酚或细菌绿素。后者分别在红色或近红外光谱区吸收强烈。在这里，八个两亲性大环（六个二氢卟酚和两个菌绿素）已被设计，合成和表征;不同的化合物在长波长吸收（610-745 nm）和外围取代基（助色，疏水/亲水基团的类型）。在15-位的甲基吡啶鎓或苯甲酸取代基提供极性“尾”，而其远端的疏水基团（在二氢卟酚中）提供亲脂性“头”，用于自发掺入有机介质中。八（细菌）二氢卟酚的特征在于静态和时间分辨吸收和荧光光谱在N，N-二甲基甲酰胺（DMF）和三个胶束环境（TX-100，CTAB，SDS），以及超快瞬态吸收研究在DMF中。在大多数情况下，观察到长寿命的激发单重态[游离碱二氢卟酚（Phi（f）= 0.14-0.20; tau（s）= 7.9- 12.1ns; Phi（isc）= 0.5），锌二氢卟酚（Phi（f）= 0.08-0.19; tau（S）= 2.0- 3.4ns; Phi（isc）= 0.6-0.8）和游离碱菌绿素（Phi（f）= 0.06-0.16; tau（s）= 1.8-4.6 ns; Phi（isc）= 0.4）]。在菌绿素的情况下，观察到最小的介质依赖性，而改变从甲基吡啶到苯甲酸的亲水基团的荧光产率和激发态寿命增加了50%。在二氢卟酚的情况下，由于溶剂与甲基吡啶鎓基团和中心锌金属的相互作用，具有甲基吡啶鎓取代的锌螯合物表现出显著的环境依赖性。总的来说，这些研究为设计红色或近红外吸收生色团提供了有价值的信息，用于掺入两亲性环境，如胶束，膜或蛋白质。
The incorporation of amphiphilic tetrapyrrole macrocycles in organized media is of great value for a variety of fundamental photochemical studies, yet work to date has chiefly employed porphyrins rather than chlorins or bacteriochlorins. The latter absorb strongly in the red or near-infrared spectral region, respectively. Here, eight amphiphilic macrocycles (six chlorins and two bacteriochlorins) have been designed, synthesized and characterized; the compounds differ in long wavelength absorption (610-745 nm) and peripheral substituents (type of auxochrome, hydrophobic/hydrophilic groups). A methyl pyridinium or benzoic acid substituent at the 15-position provides a polar "tail" whereas a hydrophobic group distal thereto (in the chlorins) provides a lipophilic "head" for the spontaneous incorporation in organized media. The eight (bacterio) chlorins are characterized by static and time-resolved absorption and fluorescence spectroscopy in N, N-dimethylformamide (DMF) and three micellar environments (TX-100, CTAB, and SDS) as well as ultrafast transient absorption studies in DMF. In most cases, a long-lived excited singlet state was observed [free base chlorins (Phi(f) = 0.14-0.20; tau(s) = 7.9-12.1 ns; Phi(isc) = 0.5), zinc chlorins (Phi(f) = 0.08-0.19; tau(S) = 2.0-3.4 ns; Phi(isc) = 0.6-0.8) and free base bacteriochlorins (Phi(f) = 0.06-0.16; tau(s) = 1.8-4.6 ns; Phi(isc) = 0.4)]. In the case of bacteriochlorins, minimal medium dependence was observed whereas changing the hydrophilic group from methyl pyridinium to benzoic acid increases the fluorescence yield and excited-state lifetime by 50%. In the case of chlorins, the zinc chelate with methyl pyridinium substitution exhibits substantial environmental dependence due to interaction of the solvent with the methyl pyridinium group and the central zinc metal. Collectively, the studies provide valuable information for the design of red or near-infrared absorbing chromophores for incorporation into amphiphilic environments such as micelles, membranes, or proteins.