Center for Oxygen Microscopy and Imaging, Department of Chemistry, Aarhus University, Arhus DK-8000, Denmark.
J Org Chem. 2009 Dec 4;74(23):9094-104. doi: 10.1021/jo9020216.
Substituent-dependent features and properties of the sensitizer play an important role in the photosensitized production of singlet oxygen, O(2)(a(1)Delta(g)). In this work, we systematically examine the effect of molecular changes in the sensitizer on the efficiency of singlet oxygen production using, as the sensitizer, oligophenylene-vinylene derivatives designed to optimally absorb light in a nonlinear two-photon process. We demonstrate that one cannot always rely on rule-of-thumb guidelines when attempting to construct efficient two-photon singlet oxygen sensitizers. Rather, as a consequence of behavior that can deviate from the norm, a full investigation of the photophysical properties of the system is generally required. For example, it is acknowledged that the introduction of a ketone moiety to the sensitizer chromophore often results in more efficient production of singlet oxygen. However, we show here that the introduction of a carbonyl into a given phenylene-vinylene can, rather, have adverse effects on the yield of singlet oxygen produced. Using these molecules, we show that care must also be exercised when using qualitative symmetry-derived arguments to predict the relationship between one-and two-photon absorption spectra.
取代基对敏化剂的特征和性质在单线态氧（O(2)(a(1)Delta(g)))的敏化产生中起着重要作用。在这项工作中，我们使用设计成在非线性双光子过程中最佳吸收光的寡聚苯乙炔衍生物作为敏化剂，系统地研究了敏化剂分子变化对单线态氧产生效率的影响。我们证明，在试图构建高效双光子单线态氧敏化剂时，不能总是依赖经验法则。相反，由于行为可能偏离常态，通常需要对系统的光物理性质进行全面调查。例如，人们承认，向敏化剂发色团中引入酮部分通常会导致单线态氧的产生更有效。然而，我们在这里表明，在给定的苯乙炔中引入羰基反而会对产生的单线态氧的产率产生不利影响。使用这些分子，我们表明，在使用定性的对称性推导的论点来预测单光子和双光子吸收光谱之间的关系时，也必须小心谨慎。
