Linear chain Au(I) dimer compounds as environmental sensors: A luminescent switch for the detection of volatile organic compounds
Linear chain Au(I) dimer compounds as environmental sensors: A luminescent switch for the detection of volatile organic compounds
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DOI：
10.1021/ja973216i
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发表时间：
1998-02-18
影响因子：
15
通讯作者：
Eisenberg, R
中科院分区：
文献类型：
--
作者：
Mansour, MA;Connick, WB;Eisenberg, R
由于暴露于挥发性有机化合物（VOCs）对健康造成的潜在危害，因此对这些物质的有效监测在环境和公共安全控制中变得突出。事实上，开发用于检测VOC的稳健且定义明确的传感器已成为深入研究的主题。1-4金属络合物作为O2、5-8 CO2、9、10 pH、11、12和金属离子13传感器的用途已被广泛研究，但它们作为VOC检测的光学传感器的用途直到最近才被开发。在1995年，Mann及其同事14报道了具有由堆叠的正方形平面络合物组成的结构的复盐[PtL 4][M（CN）4]（L）芳基异腈; M）Pt，Pd）对VOC蒸气的存在具有光谱敏感性，其中膜表现出特定有机溶剂的吸收和发射最大值（蒸发变色）特征的偏移。[15]最近，Balch及其同事[16]观察到，当无色三聚体Au（I）络合物用长波长紫外光照射时，随后与溶剂接触会产生强烈的黄色发光。在Pt复盐和三核Au（I）体系中，发射是由于分子间金属-金属相互作用产生的激发态。在这篇文章中，我们报道了二聚金（I）二硫代氨基甲酸盐配合物[Au（S2 CN（C5 H11）2）] 2（1）与VOC蒸汽的可逆相互作用，导致显着的颜色变化和发光的正“开关”。已知Au（I）的二硫代氨基甲酸盐络合物以及含有P和C供体桥连配体的其它Au（I）二聚体具有聚集和形成具有短分子间Au-Au接触的链的强烈倾向。17，18在理论和光谱研究的基础上，Fackler及其同事分析了这些相互作用的性质，18他们将Au（I）二聚体的固态发光归因于（dσ*）1（pσ）1或（dδ*）1（pσ）1激发态。在本研究中，观察发光只发生在1暴露于VOCs。在它们不存在的情况下，发射被完全熄灭。单晶结构的研究1在发光和nonemission形式强调的必要性，分子间的Au Au相互作用，以观察光致发光。配合物1是通过对文献方法的略微修改来制备的。19将2当量的KS 2CN（C5 H11）2的水溶液加入到通过将Na 2SO 3加入到NaCl饱和的K [AuCl 4]水溶液中原位产生的“AuCl 2-”溶液中，得到约1.5当量的1。从丙酮中重结晶后产率为50%。配合物经1H NMR、IR和质谱表征，元素分析表明其为分析纯。20明亮的橙子微晶化合物，1“溶剂化物，在暴露于UV光（366 nm）时显示出强烈的发光。然而，在空气中干燥数天或在真空中干燥数小时后，固体变为无色且不发光。如果将所得固体暴露于极性非质子溶剂（例如丙酮、CH 3 CN、CH 2 Cl 2和CHCl 3）的蒸气，则其再次变为橙子并恢复其发射性质;在质子溶剂（例如MeOH和EtOH）中未观察到这种效应。该过程是完全可逆的，如通过许多循环所证明的，而没有任何材料的分解，如通过1H NMR光谱所证明的。室温下的橙子固体的发射光谱由中心在631 nm的宽带组成。[21]在77 K时，该带变尖并向更高能量（604 nm）移动。无色和橙子形式的1.
The efficient monitoring of volatile organic compounds (VOCs) has gained prominence in environmental and public safety control due to the potential health hazards posed by exposure to these substances. Indeed, the development of robust and well-defined sensors for the detection of VOCs has become the subject of intensive study. 1-4 The use of metal complexes as O2, 5-8 CO2, 9, 10 pH, 11, 12 and metal ion13 sensors has been investigated extensively, but their use as optical sensors for VOC detection has not been exploited until fairly recently. In 1995, Mann and co-workers14 reported that the double salts [PtL4][M (CN) 4](L) arylisonitrile; M) Pt, Pd) having structures composed of stacked square planar complexes are spectroscopically sensitive to the presence of VOC vapors with films exhibiting shifts in absorption and emission maxima (vapochromism) characteristic for specific organic solvents. 15 More recently, Balch and co-workers16 have observed that, when a colorless trimeric Au (I) complex is irradiated with long-wavelength UV light, subsequent contact with solvent results in an intense yellow luminescence. In both the Pt double salts and the trinuclear Au (I) system, the emission is due to an excitedstate arising from intermolecular metal-metal interactions. In this communication, we report the reversible interaction of a dimeric gold (I) dithiocarbamate complex,[Au (S2CN (C5H11) 2)] 2 (1), with VOC vapors that results in both a dramatic color change and a positive “switching on” of luminescence. It is known that dithiocarbamate complexes of Au (I), as well as other Au (I) dimers containing P and C donor bridging ligands, possess a strong propensity to aggregate and form chains with short intermolecular Au ‚‚‚Au contacts. 17, 18 On the basis of theoretical and spectroscopic investigations, the nature of these interactions has been analyzed by Fackler and co-workers, 18 who assigned the solidstate luminescence of Au (I) dimers as due to either (dσ*) 1 (pσ) 1 or (dδ*) 1 (pσ) 1 excited states. In the present study, the observation of luminescence occurs only on exposure of 1 to VOCs. In their absence, the emission is completely quenched. Single-crystal structural studies of 1 in both luminescent and nonemissive forms underscore the necessity of intermolecular Au ‚‚‚Au interactions in order to observe photoluminescence. Complex 1 was prepared by a slight modification of the literature method. 19 Addition of 2 equiv of KS2CN (C5H11) 2 in water to a solution of “AuCl2-” generated in situ by the addition of Na2SO3 to a NaCl-saturated aqueous solution of K [AuCl4] affords 1 in ca. 50% yield after recrystallization from acetone. The complex was characterized by 1H NMR and IR spectroscopies and mass spectrometry and found to be analytically pure by elemental analysis. 20 The bright orange microcrystalline compound, 1 ‚solvate, exhibits intense luminescence when exposed to UV light (366 nm). However, upon drying in air for several days or in vacuo for several hours, the solid becomes colorless and nonemissive. If the resultant solid is exposed to vapors of polar aprotic solvents, eg, acetone, CH3CN, CH2Cl2, and CHCl3, it becomes orange again and regains its emissive property; this effect is not observed with protic solvents such as MeOH and EtOH. The process is fully reversible as demonstrated through numerous cycles without any decomposition of the material as evidenced by 1H NMR spectroscopy. The emission spectrum of the orange solid at room temperature is composed of a broad band centered at 631 nm. 21 At 77 K, this band sharpens and shifts to higher energy (604 nm).Single crystals of both the colorless and orange forms of 1 …