Ding Ke-Wei, Li Tao-Qi, Ge Zhong-Xue, Bu Jian-Hua, Liu Ying
State Key Laboratory of Fluorine & Nitrogen Chemicals Xi'an 710065 China
Xi'an Modern Chemistry Research Institute Xi'an 710065 China.
RSC Adv. 2018 Oct 19;8(62):35759-35767. doi: 10.1039/c8ra06873a. eCollection 2018 Oct 15.
A novel cationic tripyridiniumylporphyrin monomer, 5-[4-[2-(acryloyloxy)ethoxy]phenyl]-l0,l5,20-tris(-methyl-4-pyridiniumyl)porphyrinate zinc(ii) (ZnTrMPyP), was synthesized, and its self-aggregation in water was studied by UV-vis absorption. The monomer was copolymerized with acrylamide in water and DMSO, respectively, to prepare the water-soluble polymers P-W and P-D. The aggregation behaviour of the copolymers in aqueous solution was investigated by UV-vis absorption and fluorescence emission spectra. The polymer P-D displayed very similar absorption and emission spectra to those of ZnTrMPyP in water, indicating that the polymer chains in P-D have no significant effect on the aggregate structure of ZnTrMPyP in aqueous media. In comparison, two new absorption bands appeared in the Q band range of polymer P-W and its fluorescence spectra red shifted and the fluorescence quantum yield decreased obviously. These characteristics remained unchanged even in a good solvent for the monomer, suggesting that a new aggregation structure for the porphyrin pendants fixed by the covalent bond was formed. According to the different dispersed states of the porphyrin monomer in water and DMSO, the porphyrin pendants should distribute randomly in the P-D polymer chains while having micro-blocky sequences in polymer P-W. The association behaviour between the copolymers and tetra(-sulfonatophenyl)porphyrin, TSPP, bearing opposite charged substituents were studied by absorption and emission Spectra and further analyzed by the Benesi-Hildebrand and the Stern-Volmer methods. The results showed that relatively discrete porphyrin pendants in P-D formed a 1 : 1 stoichiometric complex with TSPP and both static and dynamic mechanisms were active in this quenching process, while the tightly associated porphyrin pendants in P-W interacted with TSPP as an entirety and static quenching was dominant in this process. This observation was in accordance with their sequential structure. The polymer P-W has a wider absorption range and higher absorption intensity in the long wavelength region than the porphyrin monomer, which can more efficiently absorb light to accomplish light harvesting in water.
合成了一种新型阳离子三吡啶基卟啉单体，5-[4-[2-(丙烯酰氧基)乙氧基]苯基]-10,15,20-三(甲基-4-吡啶基)卟啉锌(ii)(ZnTrMPyP)，并通过紫外-可见吸收光谱研究了其在水中的自聚集行为。该单体分别在水和二甲基亚砜中与丙烯酰胺共聚，制备了水溶性聚合物P-W和P-D。通过紫外-可见吸收光谱和荧光发射光谱研究了共聚物在水溶液中的聚集行为。聚合物P-D在水中的吸收光谱和发射光谱与ZnTrMPyP非常相似，表明P-D中的聚合物链对ZnTrMPyP在水介质中的聚集体结构没有显著影响。相比之下，聚合物P-W的Q带范围内出现了两个新的吸收带，其荧光光谱发生红移，荧光量子产率明显降低。即使在单体的良溶剂中，这些特性也保持不变，这表明形成了一种由共价键固定的卟啉侧基的新聚集结构。根据卟啉单体在水和二甲基亚砜中的不同分散状态，卟啉侧基在P-D聚合物链中应随机分布，而在聚合物P-W中具有微嵌段序列。通过吸收光谱和发射光谱研究了共聚物与带有相反电荷取代基的四(磺化苯基)卟啉(TSPP)之间的缔合行为，并通过贝内西-希尔德布兰德法和斯特恩-沃尔默法进行了进一步分析。结果表明，P-D中相对离散的卟啉侧基与TSPP形成了1:1化学计量比的配合物，静态和动态机制在该猝灭过程中均起作用，而P-W中紧密缔合的卟啉侧基与TSPP整体相互作用，静态猝灭在此过程中占主导地位。这一观察结果与它们的序列结构一致。聚合物P-W在长波长区域比卟啉单体具有更宽的吸收范围和更高的吸收强度，能够更有效地吸收光以实现水中的光捕获。
