Department of Chemistry, Acadia University, Wolfville, NS, Canada.
Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY.
Photochem Photobiol. 2019 Jan;95(1):293-305. doi: 10.1111/php.13000. Epub 2018 Sep 27.
There is a major need for light-activated materials for the release of sensitizers and drugs. Considering the success of chiral columns for the separation of enantiomer drugs, we synthesized an S,S-chiral linker system covalently attached to silica with a sensitizer ethene near the silica surface. First, the silica surface was modified to be aromatic rich, by replacing 70% of the surface groups with (3-phenoxypropyl)silane. We then synthesized a 3-component conjugate [chlorin sensitizer, S,S-chiral cyclohexane and ethene building blocks] in 5 steps with a 13% yield, and covalently bound the conjugate to the (3-phenoxypropyl)silane-coated silica surface. We hypothesized that the chiral linker would increase exposure of the ethene site for enhanced O -based sensitizer release. However, the chiral linker caused the sensitizer conjugate to adopt a U shape due to favored 1,2-diaxial substituent orientation; resulting in a reduced efficiency of surface loading. Further accentuating the U shape was π-π stacking between the (3-phenoxypropyl)silane and sensitizer. Semiempirical calculations and singlet oxygen luminescence data provided deeper insight into the sensitizer's orientation and release. This study has lead to insight on modifications of surfaces for drug photorelease and can help lead to the development of miniaturized photodynamic devices.
对于光激活材料在敏化剂和药物释放方面的应用有很大的需求。鉴于手性柱在对映体药物分离方面的成功，我们合成了一种 S，S-手性连接体系统，通过共价键将其连接到靠近二氧化硅表面的乙烯敏化剂上。首先，通过用（3-苯氧基丙基）硅烷取代 70%的表面基团，将二氧化硅表面修饰为富含芳基。然后，我们以 13%的收率通过 5 步反应合成了一种 3 组分的共轭物[敏化剂叶绿素、S，S-手性环己烷和乙烯砌块]，并将其共价键合到（3-苯氧基丙基）硅烷涂层的二氧化硅表面。我们假设手性连接体将增加乙烯基的暴露，从而增强基于 O 的敏化剂释放。然而，由于手性连接体有利于 1,2-二轴向取代基取向，导致敏化剂共轭物呈 U 形，从而降低了表面负载的效率。（3-苯氧基丙基）硅烷和敏化剂之间的π-π堆积进一步强调了 U 形。半经验计算和单线态氧发光数据提供了对敏化剂取向和释放的更深入了解。这项研究使我们深入了解了用于药物光释放的表面修饰，并有助于开发小型化光动力装置。
