Four iridium(III)-containing coordination polymers 1–4 using Ir(ppy)2(H2dcbpy)PF6 (L-H2, ppy = 2-phenylpyridine, H2dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) as the bridging ligand, [ZnL2]·3DMF·5H2O (1), [CdL2(H2O)2]·3DMF·6H2O (2), [CoL2(H2O)2]·2DMF·8H2O (3) and [NiL2(H2O)2]·3DMF·6H2O (4), have been synthesized and structurally characterized. The emissions from 1–4 are ascribed to a metal-to-ligand charge transfer transition (MLCT). The absolute emission quantum yields for 1–4 in single crystals were measured in air to be 0.274, 0.193, 0.001 and 0.002, respectively. The noteworthy oxygen-sensing properties of 1–4 as well as L-H2 in a single crystal were also evaluated. The Stern–Volmer quenching constant, KSV values, of 1–4 and L-H2 can be deduced to be 0.834, 2.820, 1.328, 1.111 and 2.476, respectively. The results show promising KSV values (e.g.2) that are competitive or even larger than those of many known Ir-complexes. Moreover, the short response time (e.g. compound 2) and recovery times toward oxygen of 1–4 have been measured in their single crystal forms. The reversibility experiments for 1–4 were carried out for seven repeated cycles. As a result, >75% recovery of intensity for 1 and 2 on each cycle demonstrates a high degree of reproducibility during the sensing process. It should be noted that iridium(III)-containing coordination polymers with high emission intensity and notable oxygen sensing properties are obscure, especially in the single crystal form. This, in combination with its fine reversibility, leads to success in single crystal oxygen recognition based on photoluminescence imaging. The detection limit could be 0.50% for gaseous oxygen. Moreover, the temperature effect of compound 2 in a single crystal upon application as an oxygen sensor was expected.
以 Ir(PY)2(H2dcbpy)PF6(L-H2,PY =
2-苯基吡啶,H2dcbpy = 4,4′-二羧基-2,2′-联
吡啶)为桥接
配体的四种含
铱(III)配位聚合物 1-4、合成了[Zn
L2]-3
DMF-5 (1)、[Cd
L2(
H2O)2]-3
DMF-6 (2)、[Co
L2( )2]-2
DMF-8 (3)和[Ni
L2( )2]-3
DMF-6 (4),并对它们进行了结构表征。1-4 的发射归因于
金属到
配体的电荷转移转变(MLCT)。在空气中测得的 1-4 单晶绝对发射量子产率分别为 0.274、0.193、0.001 和 0.002。此外,还评估了单晶中 1-4 和 L-H2 值得注意的氧传感特性。1-4 和 L-H2 的斯特恩-沃尔默淬火常数 KSV 值分别为 0.834、2.820、1.328、1.111 和 2.476。这些结果表明,KSV 值(例如 2)很有希望与许多已知的
铱络合物相媲美,甚至更大。此外,还测量了 1-4 的单晶形式对
氧气的短响应时间(如化合物 2)和恢复时间。1-4 的可逆性实验重复进行了七个周期。结果表明,1 和 2 在每个循环中的强度恢复率大于 75%,这表明传感过程具有很高的可重复性。值得注意的是,含
铱(III)配位聚合物具有高发射强度和显著的氧传感特性,尤其是在单晶形式下,这种特性并不明显。这一点再加上其良好的可逆性,使得基于光致发光成像的单晶
氧气识别取得了成功。对气态氧的检测限可达 0.50%。此外,化合物 2 在单晶中用作
氧气传感器时的温度效应也在意料之中。