Abstract：
Singlet oxygen is a powerful oxidant used in various applications, such as organic synthesis, medicine, and environmental remediation. Organic and inorganic photosensitizers are commonly used to generate this reactive species through energy transfer with the triplet ground state of oxygen. We describe here a series of novel benzophenazine derivatives as a promising class of photosensitizers for singlet oxygen photosensitization. In this study, we investigated the structure-activity relationship of these benzophenazine derivatives. Akin to a molecular compass, the southern fragment was first functionalized with either aromatic tertiary amines, alkyl tertiary amines, aromatic sulfur groups, alkyl sulfur groups, or cyclic ethers. Enhanced photophysical properties (in terms of triplet excited-state lifetime, absorption wavelength, triplet state energy, and O2 quenching capabilities) were obtained with cyclic ether and sulfur groups. Conversely, the presence of an amine moiety was detrimental to the photocatalysts. The western and northern fragments were also investigated and slightly undesirable to negligible changes in photophysical properties were observed. The most promising candidate was then immobilized on silica nanoparticles and its photoactivity was evaluated in the citronellol photooxidation reaction. A high NMR yield of 97 % in desired product was obtained, with only a slight decrease over several recycling runs (85 % in the fourth run). These results provide insights into the design of efficient photosensitizers for singlet oxygen generation and the development of heterogeneous systems.
摘要：
单线态氧是用于各种应用的强大氧化剂，如有机合成，医学,和环境修复。有机和无机光敏剂通常用于通过与氧的三重态基态的能量转移来产生这种反应性物质。我们在这里描述了一系列新型的二苯并嗪衍生物，作为一类有前途的单线态氧光敏剂。在这项研究中,我们研究了这些二苯并嗪衍生物的构效关系。类似于分子罗盘，南部片段首先用芳香叔胺官能化，烷基叔胺，芳香硫基团，烷基硫基团，或环醚。增强的光物理性质（就三重激发态寿命而言，吸收波长，三重态能量，和O2猝灭能力）是用环醚和硫基团获得的。相反，胺部分的存在对光催化剂是有害的。还研究了西部和北部的碎片，并观察到了光物理性质的轻微不良至可忽略的变化。然后将最有希望的候选物固定在二氧化硅纳米颗粒上，并在香茅醇光氧化反应中评估其光活性。这些结果为设计用于单线态氧产生的高效光敏剂和开发异质系统提供了见解。
