Kamada Kenji, Namikawa Tomotaka, Senatore Sébastien, Matthews Cédric, Lenne Pierre-François, Maury Olivier, Andraud Chantal, Ponce-Vargas Miguel, Le Guennic Boris, Jacquemin Denis, Agbo Peter, An Dahlia D, Gauny Stacey S, Liu Xin, Abergel Rebecca J, Fages Frédéric, D'Aléo Anthony
IFMRI, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, 563-8577, Japan.
Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan.
Chemistry. 2016 Apr 4;22(15):5219-32. doi: 10.1002/chem.201504903. Epub 2016 Feb 25.
The synthesis of boron difluoride complexes of a series of curcuminoid derivatives containing various donor end groups is described. Time-dependent (TD)-DFT calculations confirm the charge-transfer character of the second lowest-energy transition band and ascribe the lowest energy band to a "cyanine-like" transition. Photophysical studies reveal that tuning the donor strength of the end groups allows covering a broad spectral range, from the visible to the NIR region, of the UV-visible absorption and fluorescence spectra. Two-photon-excited fluorescence and Z-scan techniques prove that an increase in the donor strength or in the rigidity of the backbone results in a considerable increase in the two-photon cross section, reaching 5000 GM, with predominant two-photon absorption from the S0-S2 charge-transfer transition. Direct comparisons with the hemicurcuminoid derivatives show that the two-photon active band for the curcuminoid derivatives has the same intramolecular charge-transfer character and therefore arises from a dipolar structure. Overall, this structure-relationship study allows the optimization of the two-photon brightness (i.e., 400-900 GM) with one dye that emits in the NIR region of the spectrum. In addition, these dyes demonstrate high intracellular uptake efficiency in Cos7 cells with emission in the visible region, which is further improved by using porous silica nanoparticles as dye vehicles for the imaging of two mammalian carcinoma cells type based on NIR fluorescence emission.
本文描述了一系列含有不同供体端基的姜黄素类衍生物的二氟化硼配合物的合成。含时密度泛函理论（TD-DFT）计算证实了第二低能量跃迁带的电荷转移特性，并将最低能量带归因于“类花青”跃迁。光物理研究表明，调节端基的供体强度可使紫外-可见吸收光谱和荧光光谱覆盖从可见光到近红外区域的宽广光谱范围。双光子激发荧光和Z扫描技术证明，供体强度或主链刚性的增加会导致双光子截面显著增加，达到5000 GM，主要的双光子吸收来自S0-S2电荷转移跃迁。与半姜黄素类衍生物的直接比较表明，姜黄素类衍生物的双光子活性带具有相同的分子内电荷转移特性，因此源于偶极结构。总体而言，这项结构-关系研究能够利用一种在光谱近红外区域发射的染料优化双光子亮度（即400-900 GM）。此外，这些染料在Cos7细胞中表现出高细胞内摄取效率，在可见光区域发射，通过使用多孔二氧化硅纳米颗粒作为染料载体，基于近红外荧光发射对两种哺乳动物癌细胞类型进行成像，其效率进一步提高。
