Synthesis and characterization of highly photoresponsive fullerenyl dyads with a close chromophore antenna–C60 contact and effective photodynamic potential
作者:Long Y. Chiang、Prashant A. Padmawar、Joy E. Rogers-Haley、Grace So、Taizoon Canteenwala、Sammaiah Thota、Loon-Seng Tan、Kenneth Pritzker、Ying-Ying Huang、Sulbha K. Sharma、Divya Balachandran Kurup、Michael R. Hamblin、Brian Wilson、Augustine Urbas
DOI:10.1039/c0jm00037j
日期:——
We report the synthesis of a new class of photoresponsive C60âDCEâdiphenylaminofluorene nanostructures and their intramolecular photoinduced energy and electron transfer phenomena. Structural modification was made by chemical conversion of the keto group in C60(>DPAF-Cn) to a stronger electron-withdrawing 1,1-dicyanoethylenyl (DCE) unit leading to C60(>CPAF-Cn) with an increased electronic polarization of the molecule. The modification also led to a large bathochromic shift of the major band in visible spectrum giving measureable absorption up to 600 nm and extended the photoresponsive capability of C60âDCEâDPAF nanostructures to longer red wavelengths than C60(>DPAF-Cn). Accordingly, C60(>CPAF-Cn) may allow 2γ-PDT using a light wavelength of 1000â1200 nm for enhanced tissue penetration depth. Production efficiency of singlet oxygen by closely related C60(>DPAF-C2M) was found to be comparable with that of tetraphenylporphyrin photosensitizer. Remarkably, the 1O2 quantum yield of C60(>CPAF-C2M) was found to be nearly 6-fold higher than that of C60(>DPAF-C2M), demonstrating the large light-harvesting enhancement of the CPAF-C2M moiety and leading to more efficient triplet state generation of the C60> cage moiety. This led to highly effective killing of HeLa cells by C60(>CPAF-C2M) via photodynamic therapy (200 J cmâ2 white light). We interpret the phenomena in terms of the contributions by the extended Ï-conjugation and stronger electron-withdrawing capability associated with the 1,1-dicyanoethylenyl group compared to that of the keto group.
我们报告了一类新型光致伸缩性 C60âDCEâ 二苯胺芴纳米结构的合成及其分子内光诱导的能量和电子转移现象。通过化学方法将 C60(>DPAF-Cn) 中的酮基转化为电子吸附性更强的 1,1-二氰基乙烯(DCE)单元,对其进行了结构改造,从而得到了电子极化程度更高的 C60(>CPAF-Cn)。这种改性还导致可见光谱中的主要波段发生了很大的浴色偏移,使吸收波长达到 600 纳米,并将 C60âDCEâDPAF 纳米结构的光致发光能力扩展到比 C60(>DPAF-Cn) 更长的红色波长。因此,C60(>DPAF-Cn) 可以使用 1000â1200 nm 的光波长进行 2γ-PDT 以增强组织穿透深度。研究发现,密切相关的 C60(>DPAF-C2M) 产生单线态氧的效率与四苯基卟啉光敏剂相当。值得注意的是,C60(>CPAF-C2M) 的单线态氧量子产率比 C60(>DPAF-C2M) 高出近 6 倍,这表明 CPAF-C2M 分子的光收集能力大大增强,并导致 C60> 笼分子产生更高效的三重态。这导致 C60(>CPAF-C2M) 通过光动力疗法(200 J cmâ2 白光)高效杀死 HeLa 细胞。我们认为,与酮基相比,1,1-二氰基乙烯基具有扩展的Ï-共轭作用和更强的电子吸收能力。