Johnson Katherine R, Vittardi Sebastian B, Gracia-Nava Manuel A, Rack Jeffrey J, de Bettencourt-Dias Ana
Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA.
Dalton Trans. 2020 May 28;49(20):6661-6667. doi: 10.1039/d0dt01034k. Epub 2020 May 6.
A new pyridine-bis(carboxamide)-based ligand with a bithiophene pendant, 2Tcbx, was synthesized. Its lanthanide ion (Ln) complexes, [Ln(2Tcbx)], were isolated and their photophysical properties were explored. Upon excitation at 360 nm, these complexes display emission in the near-infrared (NIR) with efficiencies of 0.69% for Ln = Yb, 0.20% for Ln = Nd, and 0.01% for Ln = Er, respectively. Concurrent O formation was seen for all complexes, with efficiencies of 19% for the Yb complex, 25% for the Nd complex, and 9% for the Er complex. When exciting at a longer wavelength, 435 nm, only Ln emission was observed and larger efficiencies of Ln-centered emission were obtained. The lack of O generation indicates that energy pathways involving different ligand conformations, which were investigated by transient absorption spectroscopy, are involved in the sensitization process, and enable the wavelength-dependent generation of O.
合成了一种带有联噻吩侧基的新型吡啶 - 双（甲酰胺）基配体2Tcbx。分离得到了其镧系离子（Ln）配合物[Ln(2Tcbx)]，并对其光物理性质进行了研究。在360 nm激发下，这些配合物在近红外（NIR）区域发光，对于Ln = Yb，发光效率为0.69%；对于Ln = Nd，发光效率为0.20%；对于Ln = Er，发光效率为0.01%。所有配合物均观察到同时产生单线态氧，Yb配合物产生单线态氧的效率为19%，Nd配合物为25%，Er配合物为9%。当在较长波长435 nm激发时，仅观察到Ln发光，并获得了更高的以Ln为中心的发光效率。单线态氧的缺乏表明，通过瞬态吸收光谱研究的涉及不同配体构象的能量途径参与了敏化过程，并使得单线态氧的产生具有波长依赖性。
