Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA.
Chemistry, University of California, Irvine, USA.
Angew Chem Int Ed Engl. 2017 May 8;56(20):5598-5602. doi: 10.1002/anie.201701929. Epub 2017 Apr 12.
Owing to the difficulty in comprehensively characterizing nanocrystal (NC) surfaces, clear guidance for ligand design is lacking. In this work, a series of bidentate bis(pyridine) anthracene isomers (2,3-PyAn, 3,3-PyAn, 2,2-PyAn) that differ in their binding geometries were designed to find the best complementary fit to the NC surface. The efficiency of triplet energy transfer (TET) from the CdSe NC donor to a diphenylanthracene (DPA) acceptor mediated by these isomers was used as a proxy for the efficacy of orbital overlap and therefore ligand binding. 2,3-PyAn, with an intramolecular N-N distance of 8.2 Å, provided the best match to the surface of CdSe NCs. When serving as a transmitter for photon upconversion, 2,3-PyAn yielded the highest upconversion quantum yield (QY) of 12.1±1.3 %, followed by 3,3-PyAn and 2,2-PyAn. The TET quantum efficiencies determined by ultrafast transient absorption measurements showed the same trend.
由于难以全面描述纳米晶体 (NC) 表面，因此缺乏明确的配体设计指导。在这项工作中，设计了一系列二齿双吡啶蒽异构体（2,3-PyAn、3,3-PyAn、2,2-PyAn），它们在结合几何形状上有所不同，旨在找到与 NC 表面最佳互补的配体。这些异构体介导的 CdSe NC 给体到二苯基蒽 (DPA) 受体的三重态能量转移 (TET) 效率被用作轨道重叠效率的指标，因此也是配体结合的指标。2,3-PyAn 的分子内 N-N 距离为 8.2 Å，与 CdSe NC 表面的匹配度最佳。当用作光子上转换的发射器时，2,3-PyAn 的上转换量子产率（QY）最高，为 12.1±1.3 %，其次是 3,3-PyAn 和 2,2-PyAn。超快瞬态吸收测量确定的 TET 量子效率也呈现出相同的趋势。
