两种砷钼杂化多酸盐的合成、结构及变色性质

分别以2种V形羧酸[1,3-苯二甲酸(H₂BDC)和5-羟基-1,3-苯二甲酸(H₂OIP)]与钼酸铵进行反应, 得到了 2种有机酸根与无机酸根缩合构成的杂化砷钼酸盐： (NH₄)₁₇H₄[(AsMo₆O₂₁)₂(AsMo₆O₂₃)(BDC)₄]·28H₂O(1)和 (NH₄)₅Cs₈H₆[(AsMo₆O₂₁)₃(OIP)₅]·40H₂O(2). 利用单晶X射线衍射对2种化合物进行了结构分析, 发现二者均为三聚结构. 对2种化合物的光致变色及热致变色性质进行了研究, 发现在氙灯照射下2种化合物均可在5 min内变色. 当将2种化合物的样品加热到373 K时, 均出现颜色变化, 并随着温度升高颜色逐渐加深. 光致变色与热致变色过程前后的EPR检测结果均提示化合物的颜色变化与Mo^VI转化为Mo^V有关.     

柠檬酸铁（Ⅲ）络合物的光致变色现象与柠檬酸的测定

报道了柠檬酸铁（Ⅲ）络合物的光致变色现象并将其应用于微量柠檬酸（或盐）的测定。在ＰＨ１．８－２．５的酸性介质中，柠檬酸与Ｆｅ＾３＋生成的黄色络合物在光照下发生光致变色生成紫色络合物，其最大吸收波长为４９０ｎｍ；表观摩匀吸光系数ε为８０５Ｌｍ．ｍｏｌ＾－１．ｃｍ＾－１，络合物的组成比为１：１。方法的线性范围为０－－２５０ｍｇ／Ｌ，用此法测定了几种饮料的中的柠檬含量，结果令人满意。     

有机膦、胂、(月弟)合钨、钼聚多酸盐的研究 Ⅳ.烷基膦合钼聚多酸盐的制备

本文是作者在合成了一系列有机胂、有机(月弟)的钨、钼聚多酸盐后,有关若干有机膦合钼聚多酸“柄状”化合物的合成报导以及一些光学性质的测定。有关有机基团是C₂H₅,n-C₃H₇,n-C₄H₉,n-C₅H₁₁及C₆H₅CH₂。发现pH为3～5时,在不同的投料比例下都只形成一种类型的化合物[(RP)₂Mo₅O₂₁]^4-,与相应的有机胂衍生物既可形成[(RAs)₂Mo₅O₂₁]^4-又可形成[(RAs)₂Mo₆O₂₄]^4-有较大的差异。     

Keggin结构钼磷酸/聚碳酸酯复合物的制备及光致变色性质研究

近年来，多酸－有机复合材料的研究，受到了人们的广泛关注犤１犦。杂多化合物是一类含有氧桥的多核配合物，作为高质子酸，可以提供质子与有机给体形成多酸－有机复合物，这类质子化状态的复合物具有良好的光敏性，这种特性在光化学、氧化还原催化等方面显示出重要用途。聚碳酸酯是一种综合性能优良的光学材料，研究以其为基材的杂多酸－有机复合材料的基本性能，对聚碳酸酯的改性、增进对这类复合材料的理论研究以及拓宽聚碳酸酯的应用都有重要的实际意义，迄今为止，尚未见这方面的报道。本文以Keggin结构钼磷酸（简写为PMo１２）和聚…     

有机膦、胂、(月弟)合钨、钼聚多酸盐的研究(Ⅲ)——邻、间、对硝基苯胂合钼聚多酸盐的合成和鉴定

选取在不同位置上具有一个取代硝基的苯基胂酸,制得了5种新的[(ArAs)_2Mo_6O_(25)H]~(5-)型钼聚多酸盐。报道了它们的光谱及其水溶液中的电化学还原性质。讨论了邻位硝基苯胂合钼聚多酸盐在红外光谱和电化学还原行为中的异常现象。     

有机膦、胂、(月弟)合钨、钼聚多酸盐的研究 Ⅳ.烷基膦合钼聚多酸盐的制备

本文是作者在合成了一系列有机胂、有机(月弟)的钨、钼聚多酸盐后,有关若干有机膦合钼聚多酸“柄状”化合物的合成报导以及一些光学性质的测定。有关有机基团是C_2H_5,n-C_3H_7,n-C_4H_9,n-C_5H_(11)及C_6H_5CH_2。发现pH为3～5时,在不同的投料比例下都只形成一种类型的化合物[(RP)_2Mo_5O_(21)]~(4-),与相应的有机胂衍生物既可形成[(RAs)_2Mo_5O_(21)]~(4-)又可形成[(RAs)_2Mo_6O_(24)]~(4-)有较大的差异。     

多核多氧硫钼酸盐化合物的合成及质子传导性能

质子交换膜燃料电池(PEMFC)因能量转化率高、 污染小、 工作温度低、 启动速度快而被广泛应用. Nafion系列膜成本高、 结构特性模糊, 阻碍了质子传导性能的进一步提高和对传导机理的精确理解. 因此开发具有结构明确、 传导路径清晰的高质子传导率的晶态材料对于燃料电池领域具有重要意义. 本文利用有机配体5-羟基间苯二甲酸作为模板诱导[Mo₂S₂O₂]²⁺阳离子, 自组装成一种多核多氧硫钼酸盐簇[N(CH₃)₄]₂H₂· [(Mo₂S₂O₂)₈(OH)₁₆(C₈O₅H₄)₂]·22H₂O(Mo₁₆). 该化合物清晰明确的结构和结构中存在的密集氢键网络可用于进行质子传导性能的研究. 交流阻抗测试结果表明, Mo₁₆在宽温度范围内具有较高的质子传导性能. 在97%湿度(RH), 85 ℃条件下其质子传导率可达1.9×10^-2 S/cm, 表明该化合物具有作为高效质子导体的良好前景.     

乙二铵多钼酸盐NH3CH2CH2NH3Mo3O10·4.4H2O的 合成及其光致变色性质研究

利用乙二胺阳离子为模板,采用温和的反应条件制备出一种新的光致变色化合物NH3CH2CH2NH3Mo3O10·4.4H2O,经过元素分析、热重以及光谱测定,证明该化合物的无机骨架为(Mo3O10)∞^2-无穷长链。乙二胺阳离子通过氢键等超分子作用与无机骨架相连。实验发现该化合物具有良好的光致变色性能,与真空蒸镀MoO3不同的是,经紫外光照后,此化合物由白色变为红棕色,EXAFS(扩展X射线精细结构)研究结果表明紫外光照后,质子从乙二铵阳离子转移到Mo-O^-为其可能的机理。     

乙二铵多钼酸盐NH3CH2CH2NH3Mo3O10@4.4H2O的合成及其光致变色性质研究

利用乙二胺阳离子为模板,采用温和的反应条件制备出一种新的光致变色化合物NH3CH2CH2NH3Mo3O10·4.4H2O,经过元素分析、热重以及光谱测定,证明该化合物的无机骨架为(Mo3O10)∞^2-无穷长链。乙二胺阳离子通过氢键等超分子作用与无机骨架相连。实验发现该化合物具有良好的光致变色性能,与真空蒸镀MoO3不同的是,经紫外光照后,此化合物由白色变为红棕色,EXAFS(扩展X射线精细结构)研究结果表明紫外光照后,质子从乙二铵阳离子转移到Mo-O^-为其可能的机理。     

氧化钼-二氧化钛复合膜的可见光致变色性能研究

采用溶胶凝胶法制备了一系列氧化钼-二氧化钛纳米复合物, 用柠檬酸作分散剂, 将得到的纳米复合物粉末分散成溶胶, 涂膜制备了具有可见光变色性能的均匀透明的光致变色(λ≥420 nm)复合膜. 通过红外、XPS、ESR测定表明, 在氧化钼、二氧化钛复合界面上生成了Mo—O—Ti键, 此键的存在是该复合膜具有可见光致变色响应的内在原因. 在可见光的照射下, 电子从二氧化钛的价带经由Mo—O—Ti键, 被激发到氧化钼的导带上. 研究了光致变色过程的动力学, 发现光致变色反应的速率取决于膜中复合物的摩尔比([MoO₃]/[TiO₂])以及电荷转移能量(CTE).     

多酸含量对无机/高分子复合薄膜结构及光致变色性能的影响

制备了一系列不同浓度的钨磷酸/聚乙烯醇(PWA/PVA)复合薄膜, 通过红外光谱、原子力显微镜、紫外-可见吸收光谱对复合薄膜的结构和光致变色性能进行了研究. 红外光谱分析结果表明, Keggin结构钨磷酸和聚乙烯醇分子的基本结构在复合薄膜中仍然存在, 钨磷酸分子与高分子底物间存在氢键作用, 形成电荷转移桥. 原子力显微镜(AFM)结果表明复合前后PVA薄膜表面形貌发生了显著变化, 复合膜表面形貌随钨磷酸含量的不同而不同. 在紫外光照射下, 复合薄膜由无色变为蓝色. 复合膜的升色速度和褪色速度均随着钨磷酸含量的增加而加快. 这些结果表明钨磷酸含量对复合膜的微结构存在影响, 从而导致了复合膜具有不同的光致变色性能.     

Reversible Multicolor Photochromism of Dihydroazulene Crystals

The photochemical conversion of 1,8a-dihydroazulene-1,1-dicarbonitrile (DHA) to vinylheptafulvene (VHF) is a positive T-type photoswitch that is well understood in solution, but has not been explored in the solid state. Upon excitation with UV light, DHA is converted into VHF in the solid state, with a distinct color change from yellow to deep-red, and retention of crystallinity. The structure of the ring-opened product was assigned to syn-VHF using variable-temperature infrared spectroscopy, and determined by X-ray photodiffraction in a crystal enriched with the product by two-photon excitation. A radical pathway becomes an observable photoreaction channel at low temperatures, and includes a strongly colored, short-lived diradical intermediate.     

磷钨酸-PVA复合体系膜的制备和光色性研究

用旋转涂布法制得了PVA -H3PW1 2 O40 复合体系的光敏膜。研究了膜对光的响应情况 ,发现复合体系对光的响应情况与体系内各成份的浓度无关。光敏性的产生源于体系内PVA的 OH与钨磷酸阴离子中Oc的相互作用。     

Acid/Alkali Gated Photochromism of Diarylethenes with Quinoline Derivatives

Three new diarylethenes 1 – 3 combined with quinoline derivatives have been synthesized. Through controlled chemical condition of deprotonation/protonation, they presented some new irreversible photochromic phenomenons under UV/Vis light irradiation in chloroform solution. It was found that 1 – 3 had well photoisomerization upon UV/Vis light irradiation in neutral chloroform solution. Addition of acid to the solution of the ring‐opening isomers of 1 – 3 produced 1oa – 3oa , which performed reversible photochromic behavior under UV/Vis light irradiation and reversed back to 1 – 3 under neutralizing with adding lewis base. However, addtion of base to neutral soluton of the ring‐opening isomers of 1 – 3 produced 1ob – 3ob , which could not change to the deprotonated ring‐closing isomers under UV light irradiation.     

Photochromism of Peroxotungstic Acid/PVP Nanocomposite Obtained by Sol-Gel Method

Peroxotungstic acid (PTA)/PVP composite film was prepared via sol-gel method. TEM revealed that the composite films consist of peroxotungstic acid nano-grains embedded in amorphous PVP matrix. The samples were observed to exhibit reversible photochromic effect when irradiated with solar light. The iodometric titration and FT-IR spectra indicated the presence of peroxo groups (W–O–O–W) incorporated into PTA structure. EPR measurement revealed the presence of unpaired paramagnetic electrons in PTA/PVP nanocomposite gel. The UV-Vis-Nir transmittance spectra and EPR spectroscopy of sample indicate that the photochromic behaviour is due to the photo-excitation of the unpaired electrons at W–O octahedral sites of peroxotungstic acid.     

磺酸功能化的离子液体型多金属氧酸盐的光色性能

发现磺酸功能化离子液体型多金属氧酸盐(IL-POM)具有可逆光色性质,并在紫外光激发下,详细考察了[PyPS]_nH_3-nPW₁₂(n=1,3)(PyPs:吡啶丙磺酸盐)、[PyPS]₄SiW₁₂、[TEAPS]₃PW₁₂(TEAPS:3-(三乙胺基)丙磺酸盐)等样品的光致变色行为。 结果表明,磺酸化的IL-POM是一类弱的电荷转移多金属氧酸盐,但在紫外光激发下有机阳离子和POM阴离子间可以发生电子相互作用,实现W⁶⁺→W⁵⁺的还原,并形成稳定的电荷转移复合物,导致样品显色。 钨磷酸盐的光色性大大强于钨硅酸盐,且空气中避光放置可以消色。 但样品容易疲劳,着色-褪色重复性不好。 对光色机理的研究显示,有机阳离子中的-SO₃H基团作为电子供体参与了变色过程。 揭示了磺酸基团的电子供体作用,为设计电荷转移多金属氧酸盐和POM基光色材料提供了新的思路。     

Preparation and Visible-light Photochromism of Phosphomolybdic Acid/Polyvinylpyrrolidone Hybrid Film

The visible-light photochromic hybrid film was constructed by entrapping phosphomolybdic acid（PMoA） into polyvinylpyrrolidone（PVPd） networks. The microstructure, photochromic properties and mechanism were inves- tigated with transmission electron microscopy（TEM）, atomic force microscopy（AFM）, Fourier transform infrared （FTIR） spectroscopy, ultraviolet-visible（UV-Vis） spectra and X-ray photoelectron spectroscopy（XPS）. The results in- dicate that the Keggin geometry of PMoA and the basic structure of PVPd are not destroyed during the composite process. Irradiated with visible light, the transparent PMoA/PVPd film changes color from colorless to blue and ex- hibits reversible photochromism in the presence of oxygen. According to the XPS analysis, the charge-transfer bridge of N-H-O has been built between PMoA and PVPd matrix via non-covalent bonding, and the appearance of Mo5＋ species indicates that the photo-reduction process is in accordance with the proton transfer mechanism.     

Visible-light Photochromism of Phosphomolybdic Acid/ZnO Composite

A novel photochromic hybrid ZnO was synthesized by doping with phosphomolybdic acid(PMoA). It could respond to visible light and fade in color when treated with hydrogen peroxide(H₂O₂). The microstructure and photochromic properties were investigated via X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), transmission electron microscopy(TEM), ultraviolet-visible spectroscopy(UV-Vis) and X-ray photoelectron spectroscopy(XPS). The XRD patterns show that the prepared ZnO is pure and has a hexagonal wurtzite structure. The FTIR results demonstrate the existence of a strong interaction between PMoA and ZnO. Due to PMoA doping, the rough surface morphology of ZnO became smooth, as verified by the SEM images. The TEM images illustrate that pure ZnO exhibits a polycrystalline structure with irregular morphology. PMoA was wrapped on the surface of ZnO. After visible-light irradiation, the composite changed from slight yellow to blue and returned to the original color in the presence of H₂O₂. The composite had good photosensitivity and photochromic reversibility. The photochromic process was in accord with photoinduced electrons transfer mechanism.