Proton-switchable vapochromic behaviour of a platinum(II)-carboxy-terpyridine complex
Proton-switchable vapochromic behaviour of a platinum(II)-carboxy-terpyridine complex
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DOI：
10.1039/c6dt03189g
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发表时间：
2016-01-01
影响因子：
4
通讯作者：
Kato, Masako
中科院分区：
文献类型：
--
作者：
Kobayashi, Atsushi;Oizumi, Shiori;Kato, Masako
我们合成了一种羧基取代的Pt（II）-三联吡啶配合物，即[PtCl（Hctpy）] Cl（[1H] Cl; Hctpy = 4 '-carboxy-2，2'：6 '，2''-terpyridine），它在羧基的质子化/去质子化过程中表现出有趣的可切换的气相变色行为。在暴露于各种极性有机溶剂蒸气（例如，乙腈、乙醇、1-丙醇和二氯甲烷），其促进水分子的去除。[1H] Cl中心点3 H（2）O与氨水反应，得到一个去质子化的亮黄色晶体配合物[PtCl（ctpy）]中心点H2O（1个中心点H2O），该配合物具有红色荧光，最大发射波长为622 nm。尽管1个中心点H2O的颜色不受暴露于各种极性有机溶剂蒸气的影响，在饱和水蒸气中形成橙子晶体1中心点3.5H（2）O时，观察到一个有趣的汽色发光，其最大发射波长从622 nm显著红移到652 nm。X射线结构分析表明，平面中性配合物分子1形成一个单-三维柱状结构，在橙子晶体1中心点3.5H（2）O中具有分子间Pt中心点中心点Pt距离为3.518（2）埃，而阳离子分子[1H]（+）以质子化形式存在，[1H] Cl中心点H2O，生成分子间Pt中心点中心点Pt距离为3.439（2）埃的二聚体结构。这种差异表明，质子化和去质子化形式的汽致变色行为可能是由水蒸气吸附/解吸引起的结构变化引起的，这会影响分子间的Pt。Pt距离，从而改变金属-金属-配体电荷转移（MMLCT）跃迁的能量。质子化和去质子化复合物的这些对比结果清楚地表明，复合物1的亲水性受到羧基的质子化/去质子化的显著影响。此外，[1H] Cl中心点3 H（2）O和1中心点H2O之间的准可逆转化是通过将质子化和去质子化形式分别暴露于三乙胺和潮湿的盐酸蒸气来实现的。
We synthesized a carboxy-substituted Pt(II)-terpyridine complex, i.e. [PtCl(Hctpy)] Cl ([1H] Cl; Hctpy = 4'-carboxy-2,2': 6',2''-terpyridine), that shows interesting switchable vapochromic behaviour upon protonation/deprotonation of the carboxy group. The as-synthesized dark-blue amorphous-like solid [1H] Cl center dot 3H(2)O was converted to a yellow crystalline solid, [1H] Cl center dot H2O, upon exposure to various polar organic solvent vapours (e.g., acetonitrile, ethanol, 1-propanol, and dichloromethane), which promote the removal of water molecules. The reaction of [1H] Cl center dot 3H(2)O with aqueous ammonia afforded a deprotonated bright-yellow crystalline complex, i.e. [PtCl(ctpy)]center dot H2O (1 center dot H2O), which exhibits red luminescence with an emission maximum at 622nm. Although the colour of 1 center dot H2O was not affected by exposure to various polar organic solvent vapours, interesting vapochromic luminescence with a remarkable red-shift of the emission maximum from 622 to 652 nm was observed upon exposure to saturated water vapour to form orange crystalline 1 center dot 3.5H(2)O X-ray structural analysis revealed that the planar and neutral complex molecule 1 forms a one-dimensional columnar structure with an intermolecular Pt center dot center dot center dot Pt distance of 3.518(2) angstrom in the orange crystall 1 center dot 3.5H(2)O, while the cationic molecule [1H](+) in the protonated form, [1H] Cl center dot H2O, generates a dimeric structure with an intermolecular Pt center dot center dot center dot Pt distance of 3.439(2) angstrom. This difference suggests that the vapochromic behaviours of the protonated and deprotonated forms could be caused by structural changes induced by water-vapour adsorption/desorption, which affect the intermolecular Pt. Pt distance, thereby changing the energy of the metal-metal-to-ligand charge-transfer (MMLCT) transition. These contrasting results for the protonated and deprotonated complexes clearly indicate that the hydrophilicity of complex 1 is significantly affected by protonation/deprotonation of the carboxy group. In addition, quasi-reversible conversion between [1H] Cl center dot 3H(2)O and 1 center dot H2O was achieved by exposure of the protonated and deprotonated forms to triethylamine and humid hydrochloric acid vapours, respectively.