Institute of Chemical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, United Kingdom.
J Phys Chem B. 2012 Oct 4;116(39):11818-28. doi: 10.1021/jp305063e. Epub 2012 Sep 21.
Porphycenes have been shown to exhibit many advantageous properties when it comes to the application of two-photon absorption (TPA), a technique with potential use in the area of photodynamic therapy (PDT). A computational study of structure-reactivity relationships in the one- and two-photon absorption spectra of a series of 2,7,12,17-substituted porphycenes has been carried out using linear and quadratic density functional response theory. The focus has been on determining the effect on the spectra of electron donating and withdrawing substituents, the outcome of extending the conjugation lengths to these substituents, and the consequence of formation of metallo-porphycene complexes. In particular, we have looked at the use of TPA in order to improve the penetration depth of the therapeutic light dose, in terms of the position of the absorption maximum with respect to the optical window of tissue penetration, as well as the effect on the TPA cross section. The extent of conjugation was shown to be particularly crucial for increasing the TPA cross section, for both the electron withdrawing and donating substituents, while the inclusion of a metal in the center of the macrocycle was shown to benefit the absorption wavelength in terms of tissue penetration considerations.
卟吩在双光子吸收（TPA）的应用中表现出许多有利的特性，TPA 是一种在光动力疗法（PDT）领域有潜在用途的技术。使用线性和二次密度泛函响应理论对一系列 2,7,12,17-取代卟吩的单光子和双光子吸收光谱的结构-反应性关系进行了计算研究。重点是确定供电子和吸电子取代基对光谱的影响，将共轭长度扩展到这些取代基的结果，以及形成金属卟啉配合物的后果。特别是，我们研究了使用 TPA 来提高治疗光剂量的穿透深度，这涉及到吸收最大值相对于组织穿透光学窗口的位置，以及对 TPA 截面的影响。共轭程度被证明对增加 TPA 截面非常关键，无论是吸电子还是供电子取代基，而在大环的中心包含一个金属被证明有利于吸收波长，从组织穿透的角度考虑。
