Nah Min-Kook, Rho Soo-Gyun, Kim Hwan Kyu, Kang Jun-Gill
Center for Smart Light-Harvesting Materials and Department of Advanced Materials, Hannam University, Deajeon 306-791, Korea.
J Phys Chem A. 2007 Nov 15;111(45):11437-43. doi: 10.1021/jp0753979. Epub 2007 Oct 18.
Lanthanide complexes with benzothiazole derivatives (Btz-R, R = OCH(3) and OH) and terpyridine (tpy) ligands were synthesized, and their photophysical properties were precisely investigated. The free Btz-OCH(3) ligand in toluene, excited with UV light, produced the normal emission bands around 410 nm, whereas Btz-OH produced a strong excited-state intramolecular proton transfer (ESIPT) band at 510 nm. The Ln(III) complexes (Ln = Nd, Er, and Yb) exhibited sensitized near-IR luminescence when the Btz-R ligands were excited. The sensitized luminescence quantum yields (Phi(Ln)) of the lanthanide complexes were markedly enhanced by ESIPT: for [Nd(Btz-R)(tpy)] in toluene solution, Phi(Ln) = 0.04% for Btz-OCH(3) and 0.39% for Btz-OH. The sensitized luminescence of the Er(III) complexes (Phi(Ln) = 0.002% for Btz-OCH(3) and 0.009% for Btz-OH) was less efficient than that of the Nd(III) complexes. This difference is due to the smaller energy gap between the emitting and ground levels of the Er(III) ion. The rate constants for the energy transfer from Btz-R to Ln(III) were about approximately 10(9) s(-1), as evaluated by the Förster resonance energy transfer mechanism.
合成了镧系元素与苯并噻唑衍生物（Btz-R，R = OCH(3) 和 OH）以及三联吡啶（tpy）配体的配合物，并对其光物理性质进行了精确研究。甲苯中的游离 Btz-OCH(3) 配体在紫外光激发下，在 410 nm 左右产生正常发射带，而 Btz-OH 在 510 nm 处产生强的激发态分子内质子转移（ESIPT）带。当 Btz-R 配体被激发时，Ln(III) 配合物（Ln = Nd、Er 和 Yb）表现出敏化近红外发光。镧系配合物的敏化发光量子产率（Phi(Ln)）通过 ESIPT 显著提高：对于甲苯溶液中的 [Nd(Btz-R)(tpy)]，Btz-OCH(3) 的 Phi(Ln) = 0.04%，Btz-OH 的 Phi(Ln) = 0.39%。Er(III) 配合物的敏化发光（Btz-OCH(3) 的 Phi(Ln) = 0.002%，Btz-OH 的 Phi(Ln) = 0.009%）比 Nd(III) 配合物的效率低。这种差异是由于 Er(III) 离子发射和基态能级之间的能隙较小。通过 Förster 共振能量转移机制评估，从 Btz-R 到 Ln(III) 的能量转移速率常数约为 10(9) s(-1)。
