Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, USA.
J Am Chem Soc. 2012 Jan 11;134(1):654-64. doi: 10.1021/ja209718g. Epub 2011 Dec 9.
A 'molecular clip' featuring a near-IR emitting fluorophore, BF(2)-chelated tetraarylazadipyrromethane (aza-BODIPY) covalently linked to two porphyrins (MP, M = 2H or Zn) has been newly synthesized to host a three-dimensional electron acceptor fullerene via a 'two-point' metal-ligand axial coordination. Efficient singlet-singlet excitation transfer from (1)ZnP* to aza-BODIPY was witnessed in the dyad and triad in nonpolar and less polar solvents, such as toluene and o-dichlorobenzene, however, in polar solvents, additional electron transfer occurred along with energy transfer. A supramolecular tetrad was formed by assembling bis-pyridine functionalized fullerene via a 'two-point' metal-ligand axial coordination, and the resulted complex was characterized by optical absorption and emission, computational, and electrochemical methods. Electron transfer from photoexcited zinc porphyrin to C(60) is witnessed in the supramolecular tetrad from the femtosecond transient absorption spectral studies. Further, the supramolecular polyads (triad or tetrad) were utilized to build photoelectrochemical cells to check their ability to convert light into electricity by fabricating FTO/SnO(2)/polyad electrodes. The presence of azaBODIPY and fullerene entities of the tetrad improved the overall light energy conversion efficiency. An incident photon-to-current conversion efficiency of up to 17% has been achieved for the tetrad modified electrode.
一种“分子夹”，其特征在于近红外发射荧光团 BF(2)螯合四芳基偶氮二吡咯甲烷（aza-BODIPY）与两个卟啉（MP，M=2H 或 Zn）共价连接，通过“两点”金属-配体轴向配位来容纳三维电子受体富勒烯。在非极性和极性较小的溶剂（如甲苯和邻二氯苯）中，在偶联物和三联体中见证了从（1）ZnP*到 aza-BODIPY 的有效单重态-单重态激发转移，然而，在极性溶剂中，除了能量转移外，还发生了额外的电子转移。通过“两点”金属-配体轴向配位组装双吡啶功能化富勒烯形成超分子四联体，并用光学吸收和发射、计算和电化学方法对所得配合物进行了表征。从飞秒瞬态吸收光谱研究中见证了从光激发锌卟啉到 C(60)的电子转移在超分子四联体中发生。此外，超分子聚体（三联体或四联体）被用于构建光电化学电池，以通过制造 FTO/SnO(2)/聚体电极来检查它们将光转化为电的能力。四联体中存在 azaBODIPY 和富勒烯基团提高了整体的光能转换效率。四联体修饰电极的光电流转换效率高达 17%。
