Sensitized luminescence of Eu and Tb macrocyclic complexes bearing benzophenone antennae
Sensitized luminescence of Eu and Tb macrocyclic complexes bearing benzophenone antennae
复制标题
DOI：
10.1016/j.jlumin.2006.05.007
复制
发表时间：
2007-09-01
影响因子：
3.6
通讯作者：
Hirai, Takayuki
中科院分区：
文献类型：
--
作者：
Shiraishi, Yasuhiro;Furubayashi, Yugo;Hirai, Takayuki
本文研究了以一个或四个二苯甲酮（BP）为天线的镧系（Ln = Eu ~（3+），Tb ~（3+））大环大环环戊二烯（1，4，7，10-四氮杂环十二烷）配合物（LnL_1和LnL_4）在水中的敏化发光行为。尽管由于四个天线，EuL 4的摩尔消光系数更高，但它仅显示EuL 1的发光强度的三十分之一。BP天线的三重激发态（ET）能级仅比Eu ~（3+）的D-5（2）激发态高几kJ mol ~（-1），从而促进了Eu ~（3+）的D-5（2）到基态BP天线的反向能量转移（BET）。在EuL 4轴承四天线，BET发生更迅速比EuL 1，从而表现出更弱的发光。对于Tb配合物，BP天线的ET与Tb 3+的D-5（4）激发态之间的能隙足够大（> 13 kJ mol（-1）），使得实际上不发生BET。然而，TbL 4的发光强度比TbL 1的发光强度低（三分之二）。时间分辨发光测量表明，TbL 4中Tb 3+的水化数是TbL 1中的两倍。这是因为TbL 4上的配体的结构畸变，由BP天线之间的分子内偶极-偶极相互作用引起，允许更多数量的H2O分子与Tb配位，从而导致通过O-H振荡器的强Tb发光猝灭。(C)2006 Elsevier B. V.保留所有权利。
Sensitized luminescence behavior of lanthanide (Ln = Eu3+, Tb3+) macrocyclic cyclen (1,4,7,10-tetraazacyclododecane) complexes bearing one or four benzophenone (BP) moieties as antenna (LnL1 and LnL4) has been studied in water. Despite higher molar extinction coefficient of EuL4 owing to four antennae, it shows only one-thirtieth the luminescence intensity of EuL1.. Energy level of triplet excited-state of BP antenna (ET) is only a few kJ mol(-1) higher than that of D-5(2) excited-state of EU3+, thus promoting a back energy transfer (BET) from D-5(2) of Eu3+ to ground-state BP antennae. On EuL4 bearing four antennae, BET occurs more rapidly than that on EuL1, thus exhibiting much weaker luminescence. For Tb complexes, the energy gap between ET of BP antenna and D-5(4) excited state of Tb3+ is large enough ( > 13 kJ mol(-1)), such that practically no BET occurs. The luminescence intensity of TbL4 is, however, lower (two-third) than that of TbL1. Time-resolved luminescence measurement reveals that hydration number of Tb3+ within TbL4 is twice that within TbL1. This is because the structural distortion of ligands on TbL4, caused by an intramolecular dipole-dipole interaction among the BP antennae, allows coordination of higher number of H2O molecules to Tb, thus leading to a strong Tb luminescence quenching via O-H oscillators. (C) 2006 Elsevier B.V. All rights reserved.