Sharma Ritambhara, Gobeze Habtom B, D'Souza Francis, Ravikanth Mangalampalli
Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai, 400 076, India.
Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017, USA.
Chemphyschem. 2016 Aug 18;17(16):2516-24. doi: 10.1002/cphc.201600317. Epub 2016 May 31.
All-BODIPY-based (BODIPY=boron-dipyrromethene) donor-acceptor systems capable of wide-band absorbance leading to efficient energy transfer in the near-IR region are reported. A covalently linked 3-pyrrolyl BODIPY-BODIPY dimer building block bearing an ethynyl group at the meso-aryl position is synthesized and coupled with three different monomeric BODIPY/pyrrolyl BODIPY building blocks with a bromo/iodo group under Pd(0) coupling conditions to obtain three covalently linked 3-pyrrolyl-BODIPY-based donor-acceptor oligomers in 19-29 % yield. The oligomers are characterized in detail by 1D and 2D NMR spectroscopy, high-resolution mass spectrometry, and optical spectroscopy. Due to the presence of different functionalized BODIPY derivatives in the oligomers, panchromatic light capture (300-725 nm) is witnessed. Fluorescence studies reveal singlet-singlet energy transfer from BODIPY monomer to BODIPY dimer leading to emission in the 700-800 nm range. Theoretical modeling according to the Förster mechanism predicts ultrafast energy transfer due to good spectral overlap of the donor and acceptor entities. Femtosecond transient absorption studies confirm this to be the case and thus show the relevance of the currently developed all-BODIPY-based energy-funneling supramolecular sytems with near-IR emission to solar-energy harvesting applications.
据报道，所有基于BODIPY（BODIPY=硼二吡咯亚甲基）的供体-受体体系都能够实现宽带吸收，从而在近红外区域实现高效的能量转移。合成了一种在中芳基位置带有乙炔基的共价连接的3-吡咯基BODIPY-BODIPY二聚体结构单元，并在钯（0）偶联条件下与三种带有溴/碘基团的不同单体BODIPY/吡咯基BODIPY结构单元偶联，以19-29%的产率获得了三种共价连接的基于3-吡咯基-BODIPY的供体-受体低聚物。通过一维和二维核磁共振光谱、高分辨率质谱和光学光谱对这些低聚物进行了详细表征。由于低聚物中存在不同功能化的BODIPY衍生物，因此观察到了全色光捕获（300-725 nm）。荧光研究表明，从BODIPY单体到BODIPY二聚体的单重态-单重态能量转移导致在700-800 nm范围内发射。根据Förster机制进行的理论建模预测，由于供体和受体实体的良好光谱重叠，能量转移超快。飞秒瞬态吸收研究证实了这一点，从而表明了当前开发的具有近红外发射的全基于BODIPY的能量漏斗超分子体系在太阳能收集应用中的相关性。
