Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
Molecules. 2021 Feb 19;26(4):1102. doi: 10.3390/molecules26041102.
Functional molecule-based solids built of metal complexes can reveal a great impact of external stimuli upon their optical, magnetic, electric, and mechanical properties. We report a novel molecular material, {[Eu(HO)(pyrone)][Co(CN)]}·HO (, = 2; , = 1), which was obtained by the self-assembly of Eu and [Co(CN)] ions in the presence of a small 2-pyrrolidinone (pyrone) ligand in an aqueous medium. The as-synthesized material, , consists of dinuclear cyanido-bridged {EuCo} molecules accompanied by two H-bonded water molecules. By lowering the relative humidity (RH) below 30% at room temperature, undergoes a single-crystal-to-single-crystal transformation related to the partial removal of crystallization water molecules which results in the new crystalline phase, . Both and solvates exhibit pronounced Eu-centered visible photoluminescence. However, they differ in the energy splitting of the main emission band of a D → F origin, and the emission lifetime, which is longer in the partially dehydrated . As the ↔ structural transformation can be repeatedly reversed by changing the RH value, the reported material shows a room-temperature switching of detailed luminescent features including the ratio between emission components and the emission lifetime values.
基于功能分子的固体由金属配合物构成，可以揭示外部刺激对其光学、磁性、电学和机械性能的巨大影响。我们报告了一种新型的分子材料{[Eu(HO)(pyrone)][Co(CN)]}·HO（，= 2；，= 1），它是通过在水溶液中存在少量 2-吡咯烷酮（吡酮）配体的情况下，Eu 和 [Co(CN)]离子自组装而成的。所合成的材料，由双核氰基桥联{EuCo}分子组成，同时伴有两个氢键合的水分子。通过将室温下的相对湿度（RH）降低到 30%以下，发生了一个涉及部分去除结晶水分子的单晶到单晶的转变，生成了新的晶相。和 都以溶剂化形式存在，表现出明显的 Eu 中心可见光致发光。然而，它们在 D→F 起源的主要发射带的能量分裂和发射寿命方面存在差异，部分脱水的 具有更长的发射寿命。由于 ↔ 结构转变可以通过改变 RH 值反复逆转，所报道的材料表现出室温下发光特征的详细切换，包括发射成分的比例和发射寿命值。
