Ihalagedara Hasanuwan B, Xu QianFeng, Greer Alexander, Lyons Alan M
The Graduate Center of the City University of New York, New York, New York, USA.
Department of Chemistry, College of Staten Island, City University of New York, New York, New York, USA.
Photochem Photobiol. 2025 Jan-Feb;101(1):167-179. doi: 10.1111/php.13969. Epub 2024 Jun 2.
Photochemical generation of singlet oxygen (O) often relies on homogenous systems; however, a dissolved photosensitizer (PS) may be unsuitable for some applications because it is difficult to recover, expensive to replenish, and hazardous to the environment. Isolation of the PS onto a solid support can overcome these limitations, but implementation faces other challenges, including agglomeration of the solid PS, physical quenching of O by the support, photooxidation of the PS, and hypoxic environments. Here, we explore a superhydrophobic polydimethylsiloxane (SH-PDMS) support coated with the photosensitizer 5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H-porphyrin (TFPP). This approach seeks to address the challenges of a heterogeneous system by using a support that exhibits low O physical quenching rates, a fluorinated PS that is chemically resistant to photooxidation, and a superhydrophobic surface that entraps a layer of air, thus preventing hypoxia. Absorbance and fluorescence spectroscopy reveal the monomeric arrangement of TFPP on SH-PDMS surfaces, a surprising but favorable characteristic for a solid-phase PS on O yields. We also investigated the effect of incident wavelength on O yields for TFPP in aqueous solution and immobilized on SH-PDMS and found overall yields to be dependent on the absorption coefficient, while the yield per absorbed photon exhibited wavelength independence, in accordance with Kasha-Vavilov's rule.
单线态氧（O）的光化学产生通常依赖于均相体系；然而，溶解的光敏剂（PS）可能不适用于某些应用，因为它难以回收、补充成本高且对环境有害。将PS固定在固体载体上可以克服这些限制，但实施过程面临其他挑战，包括固体PS的团聚、载体对O的物理猝灭、PS的光氧化以及缺氧环境。在此，我们探索了一种涂有光敏剂5,10,15,20-四（五氟苯基）-21H,23H-卟啉（TFPP）的超疏水聚二甲基硅氧烷（SH-PDMS）载体。这种方法旨在通过使用一种具有低O物理猝灭速率的载体、一种对光氧化具有化学抗性的氟化PS以及一种截留一层空气从而防止缺氧的超疏水表面来解决非均相体系的挑战。吸光度和荧光光谱揭示了TFPP在SH-PDMS表面的单体排列，这对于固相PS的O产率来说是一个令人惊讶但有利的特性。我们还研究了入射波长对水溶液中以及固定在SH-PDMS上的TFPP的O产率的影响，发现总体产率取决于吸收系数，而每吸收一个光子的产率表现出与波长无关，这符合卡沙-瓦维洛夫规则。
