N3染料对F-的高选择性光学传感性质

采用紫外-可见吸收光谱和荧光光谱滴定方法研究了N3染料,cis-Ru(Hedcbpy)2(NCS)2(H2dcbpy=4,4'-二羧酸-2,2'-联吡啶),在二甲基亚砜(DMSO)溶液中对F-、Cl-和Br-的识别行为.结果表明,F-能引起N3的吸收光谱和荧光光谱的明显变化,能作为高选择性的荧光和比率色度F-专感器.N3与P相互作用产生一个大的荧光增强因子40,在已报道的基于Ru(Ⅱ)配合物的F-传感器中较为罕见.     

酰胺硫脲类衍生物对阴离子的识别作用研究

应用紫外-可见吸收光谱和荧光光谱考察了一种酰胺硫脲类衍生物在二甲基亚砜(DMSO)中与F-、C1-、Br-、CH3CO2-、H2PO4-和HSO4-的相互作用.结果表明,该类主体分子能与阴离子形成结合比为1:1的氢键配合物,荧光光谱显示它们对F-和H2PO4-有突出的响应灵敏度,可选择性识别F-和H2PO4-.     

一种含咔唑基团的混配型钌(Ⅱ)配合物的合成、表征和酸碱性质研究

合成了钌(Ⅱ)配合物cis-[Ru(HL)(Hdcbpy)(NCS)2]-·[N(C4H9)4] (HL=2-(9-乙基-9H-3-咔唑基)-1H-咪唑[4,5-f][1,10]邻菲哕啉,H2dcbpy=4,4'-二羧酸-2,2'-联吡啶).采用元素分析、核磁共振氢谱、红外光谱、紫外-可见吸收光谱、质谱(MS)对配合物进行了表征.通过紫外-可见吸收光谱和稳态荧光光谱,研究了该配合物的基态和激发态酸碱性质.结果表明该配合物在基态时能发生5步质子化/去质子化反应,表现出基于光致发光强度和激发态能量转移途径的质子化/去质子化诱导的分子开关性质.     

席夫碱类高选择性氟离子化学传感器的研究

以邻羟基萘甲醛和水合肼合成了席夫碱类化合物荧光黄101(DHNA),在F-存在的情况下,其紫外可见光谱和荧光光谱都发生明显的变化,同时溶液颜色和荧光的变化可以通过肉眼直接观测到.在Cl-、Br-、1-、HSO4-、H2PO4-;等干扰离子存在的情况下,DHNA对F-具有良好的选择性.因此,荧光黄101可用于制备检测F-的高灵敏度颜色.荧光传感器.     

酰腙类衍生物作为阴离子荧光探针的研究

本文设计合成了含偶氮酰腙类受体分子1,2-羟基-5-(4-硝基苯偶氮基)苯甲醛-p-硝基苯甲酰腙。用UV-Vis和荧光光谱考察了其与AcO-、H2PO4-、F-、Cl-、Br-和I-阴离子的作用。当加入AcO-、F-和H2PO4-时,受体分子的吸收光谱发生明显的红移,同时溶液颜色由无色变为紫红色。更为重要的是受体1对阴离子表现出荧光光谱的比率变化。最后通过在DMSO-d6中的核磁滴定实验研究受体1和F-相互作用的本质。     

3-苄基-2,4-戊二酮的合成及与铕(Ⅲ)配合物的光谱和荧光性能

利用β-二酮烃基化反应合成了一种配体3-苄基-2,4-戊二酮(BPD),用红外光谱与核磁共振谱对产物的结构进行确定.以BPD为第一配体和邻菲罗啉(Phen)为第二配体,与稀土铕离子制备了配合物,并对其C,H,N的组成百分比按实验分子式[Eu(BPD)3Phen或EuC48H50N2O6]作了测定和计算.并用红外光谱和紫外-可见吸收光谱法对配体进行表征,并用荧光光谱检测其荧光发光性能.     

一个新型钌(Ⅱ)配合物对F~-的双重光谱识别

采用紫外-可见光谱和荧光光谱滴定方法研究了钌(Ⅱ)配合物[Ru(bpy)(H2iip)2](ClO4)2[bpy=2,2'-联吡啶,H2iip=2-吲哚基-咪唑并[4,5-f][1,10]-邻菲罗啉]在DMSO溶液中对卤素离子的识别性质.结果表明该配合物能比色和荧光双重光谱高选择性识别F-.     

含水溶液中香豆素类探针对碘离子的荧光增强识别

设计合成了新型含硫代半卡巴肼结构的香豆素类I-荧光分子探针CI,其结构用1H NMR,13C NMR,GC/MS和元素分析进行了表征,并考察了其光谱性能.结果表明CI在中性缓冲溶液中,在常见阴离子(F-,Cl-,Br-,I-,AcO-,HSO-4,H2PO-4)中能够专一性地识别I-.滴加I-后引起吸收光谱蓝移80 nm,荧光光谱蓝移6 nm,荧光增强5.9倍,溶液荧光由黄绿色变为亮蓝色.其它阴离子的存在并未干扰CI对I-的检测.     

N-对氯苯甲酰基-N'-芳酰氨基硫脲对一些阴离子的识别性能研究

应用紫外-可见吸收光谱和荧光光谱考察了N-对氯苯甲酰基-N'-芳酰氨基硫脲在二甲基亚砜(DMSO)中与F-、Cl-、Br-、I-、CH3CO2-和HSO4-的相互作用。结果表明,该类主体分子b和d能与阴离子形成结合比为1∶1的氢键配合物,荧光光谱显示它们对F-有突出的响应灵敏度,可选择性识别F-。     

Salen型化合物的合成、表征及性质

设计合成了两种新型Salen配体H2L1(N,N?-3-二甲氧基-邻羟苯亚甲基-4,5-二甲氧基-1,2-苯二胺)、H2L2(N,N?-3-二甲氧基-邻羟苯亚甲基-4,5-二硝基-1,2-苯二胺)及相应的镍、铜、锌金属配合物ML1、ML2(M=Ni,Cu,Zn),并分别采用核磁共振(1HNMR)波谱、紫外-可见(UV-Vis)吸收光谱、红外(IR)光谱、质谱(MS)和元素分析进行了表征.探究了配体及其配合物的荧光性质.研究发现,与H2L1相比,配体H2L2由于引入强的吸电子基团―NO2,其荧光强度减弱.相对于配体,锌离子的配位则导致其配合物的荧光强度增强,而镍和铜离子的嵌入则使得配合物ML1、ML2(M=Ni,Cu)荧光猝灭.对电化学性质的研究表明,CuL1的氧化还原过程为准可逆的单电子过程;与H2L2相比,配体H2L1由于引入强的给电子基团―OCH3,其溶液的导电性降低.     

Vapor-controlled linkage isomerization of a vapochromic bis(thiocyanato)platinum(II) complex: new external stimuli to control isomerization behavior

We synthesized a novel Pt(II)-diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)(2)(H(2)dcbpy)] (1; H(2)dcbpy =4,4'-dicarboxy-2,2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl(2)(H(2)dcbpy)] and KSCN in aqueous solution at 0 °C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)(2)(H(2)dcbpy)] (1SS·H(2)O), as a nonluminescent orange solid. Interestingly, 1SS·H(2)O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)(2)(H(2)dcbpy)] (1NN·3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H(2)dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS·H(2)O to acetone vapor at room temperature, and about 80% of 1SS·H(2)O was found to be converted to 1SN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (λ(irr.) = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H(2)dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN·4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding ability among the carboxyl groups of the H(2)dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular switching function driven by vapor molecules.     

Charge-transfer emission involving three-coordinate organoboron: V-shape versus U-shape and impact of the spacer on dual emission and fluorescent sensing

New V-shaped bifunctional organosilicon compounds that contain an electron acceptor, B(Mes)2, and an electron donor, N(1-naph)Ph, with the formulae Ph2Si{p-C6H4B(Mes)2}{p-C6H4N(1-naph)ph)} (1), Ph2Si{p-C6H4(Mes)2}{p-biphenyl-N(1-naph)ph} (2), and Si{p-C6H4B(Mes)2}2{p-C6H4N(1-naph)ph)}2 (3) have been synthesized as model compounds for the investigation of through-space charge-transfer emission involving triarylboron and triarylamino centers. The photophysical properties of the new bifunctional organosilicon compounds are compared to two U-shaped compounds sBN and BN in which the boron acceptor and the amino donor groups are linked together by a rigid 1,10-naphthyl group. The results of our investigation establish that dual emission pathways, namely through-space donor-acceptor charge transfer and pi-pi* transitions coexist in the V-shaped molecules 1-3, while charge transfer emission is dominant in the U-shaped molecules. It is found that depending on the geometry of the linker and the BN separation distance, the compound either displays dual emission bands simultaneously or single emission band. In addition, the dual emission pathways in these molecules can be selectively switched on or off by using fluoride ions. The sensitivity of response to fluoride ions by these molecules is also found to be highly dependent on the geometry of the linker and the BN separation distance. The V-shaped molecules are found to be "turn-on" sensors to fluorides with a much higher sensitivity than the U-shaped molecules.     

Induction-driven stabilization of the anion-π interaction in electron-rich aromatics as the key to fluoride inclusion in imidazolium-cage receptors

Intermolecular interactions that involve aromatic rings are key processes in both chemical and biological recognition. It is common knowledge that the existence of anion-π interactions between anions and electron-deficient (π-acidic) aromatics indicates that electron-rich (π-basic) aromatics are expected to be repulsive to anions due to their electron-donating character. Here we report the first concrete theoretical and experimental evidence of the anion-π interaction between electron-rich alkylbenzene rings and a fluoride ion in CH(3)CN. The cyclophane cavity bridged with three naphthoimidazolium groups selectively complexes a fluoride ion by means of a combination of anion-π interactions and (C-H)(+)···F(-)-type ionic hydrogen bonds. (1)H NMR, (19)F NMR, and fluorescence spectra of 1 and 2 with fluoride ions are examined to show that only 2 can host a fluoride ion in the cavity between two alkylbenzene rings to form a sandwich complex. In addition, the cage compounds can serve as highly selective and ratiometric fluorescent sensors for a fluoride ion. With the addition of 1 equiv of F(-), a strongly increased fluorescence emission centered at 385 nm appears at the expense of the fluorescence emission of 2 centered at 474 nm. Finally, isothermal titration calorimetry (ITC) experiments were performed to obtain the binding constants of the compounds 1 and 2 with F(-) as well as Gibbs free energy. The 2-F(-) complex is more stable than the 1-F(-) complex by 1.87 kcal mol(-1), which is attributable to the stronger anion-π interaction between F(-) and triethylbenzene.     

Luminescent cyclometalated Rh(III), Ir(III), and (DIP)2Ru(II) complexes with carboxylated bipyridyl ligands: synthesis, X-ray molecular structure, and photophysical properties

Luminescent cyclometalated rhodium(III) and iridium(III) complexes of the general formula [M(ppy) 2(N (wedge)N)][PF 6], with N (wedge)N = Hcmbpy = 4-carboxy-4'-methyl-2,2'-bipyridine and M = Rh ( 1), Ir ( 2) and N (wedge)N = H 2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine and M = Rh ( 3), Ir ( 4), were prepared in high yields and fully characterized. The X-ray molecular structure of the monocarboxylic iridium complex [Ir(ppy) 2(Hcmbpy)][PF 6] ( 2) was also determined. The photophysical properties of these compounds were studied and showed that the photoluminescence of rhodium complexes 1 and 3 and iridium complexes 2 and 4 originates from intraligand charge-transfer (ILCT) and metal-to-ligand charge-transfer/ligand-centered MLCT/LC excited states, respectively. For comparison purposes, the mono- and dicarboxylic acid ruthenium complexes [Ru(DIP) 2(Hcmbpy)][Cl] 2 ( 5) and [Ru(DIP) 2(H 2dcbpy)][Cl] 2 ( 6), where DIP = 4,7-diphenyl-1,10-phenanthroline, were also prepared, whose emission is MLCT in nature. Comparison of the photophysical behavior of these rhodium(III), iridium(III), and ruthenium(II) complexes reveals the influence of the carboxylic groups that affect in different ways the ILCT, MLCT, and LC states.     

Vapour-adsorption and chromic behaviours of luminescent coordination polymers composed of a Pt(II)-diimine metalloligand and alkaline-earth metal ions

Four new bimetallic coordination polymers (CPs), {M[Pt(CN)(2)(5,5'-dcbpy)]·4H(2)O}(n) (M = Mg(2+), Ca(2+), Sr(2+), Ba(2+); 5,5'-H(2)dcbpy = 5,5'-dicarboxy-2,2'-bipyridine) were synthesized using four alkaline-earth metal ions and a Pt(II)-diimine metalloligand [Pt(CN)(2)(5,5'-H(2)dcbpy)]. All four CPs are isomorphous with the Zn complex, {Zn[Pt(CN)(2)(5,5'-dcbpy)]·4H(2)O}(n), which exhibits effective metallophilic interactions between Pt(II) ions. These CPs exhibited colourful thermochromic behaviour and solid-state solvatochromic-like behaviours when suspended in various solvents. Thermogravimetric analysis and vapour-adsorption measurements revealed that the CPs can reversibly adsorb water and MeOH vapours. The emission energy of the triplet metal-metal-to-ligand charge-transfer ((3)MMLCT) state varied markedly upon guest adsorption/desorption. The chromic and vapour-adsorption properties of these CPs depend strongly on the cross-linking M(2+) ions.     

Photophysical and density functional studies of the interaction of a flavone derivative with the halides

The synthesis, photophysical behavior, and anion-sensing ability of a fluorescent molecular system, N-(3-methoxy-4-oxo-2-phenyl-4H-chromen-7-yl)-benzamide (1H), designed and developed with a view to sensing fluoride ions, are reported. NMR and density functional studies on the system have been carried out to determine the nature of the interaction between 1H and X- (X = halogen atom) responsible for fluoride-induced dramatic changes in the absorption and emission properties of 1H. The color change of 1H, which can be observed by the naked eye, is found specific to fluoride ion; it is unaffected by the presence of a large excess of Cl-, Br-, and I-, thus rendering 1H as a selective fluoride ion sensor in micromolar concentration in the visible region. The changes in the fluorescence behavior of 1H, specifically, the formation of an additional long-wavelength emission band in the presence of fluoride ion, allow ratiometric fluorescence signaling of the fluoride ion as well. The results suggest that abstraction of the acidic proton of 1H by the F- leading to the formation of 1- is responsible for the spectral changes that allow signaling of the F-. Density functional calculations of the optimized geometrical parameters and charge densities of the 1H...halide complexes confirm the proton abstraction mechanism of the signaling of F-. Calculations of the transition energies of the 1H, 1-, and 1H...F- (hydrogen-bonded complex) show that only 1- is responsible for the long-wavelength absorption and emission band observed in the presence of F-.     

席夫碱型环磷腈类化合物的合成及光谱性质

通过亲核取代反应, 在2,2'-联苯二酚氧基环氯磷腈母体N₃P₃(O₂C₁₂H₈)₂Cl₂ (1)和N₃P₃(O₂C₁₂H₈)Cl₄ (2)上引入2-醛基吡啶与对胺基苯酚形成的席夫碱侧基, 合成了两种新型环磷腈化合物N₃P₃(O₂C₁₂H₈)₂(p-O-Ph-N＝C-Py)₂ (3)和N₃P₃(O₂C₁₂H₈)(p-O-Ph-N＝C-Py)₄ (4), 这些化合物是一类能形成配合物的多齿配体. 通过元素分析, IR, ¹H NMR, ³¹P NMR和TOFMS确定其结构, 研究了它们的吸收光谱和荧光光谱. H^＋和Cu^＋离子对其光谱性质的影响研究表明两种化合物的吸收和荧光光谱对H^＋和Cu^＋离子异常敏感, 因而在作为这些阳离子的荧光探针方面具有应用前景.     

Diazaborolyl-boryl push-pull systems with ethynylene-arylene bridges as 'turn-on' fluoride sensors

Two linear π-conjugated systems with 1,3-diethyl-1,3,2-benzodiazaborolyl [C(6)H(4)(NEt)(2)B-] as a donor group and dimesitylboryl (-BMes(2)) as acceptor were synthesised with -ethynylene-phenylene- (-C[triple bond, length as m-dash]C-1,4-C(6)H(4)-, 3) and -ethynylene-thiophene- (-C[triple bond, length as m-dash]C-2,5-C(4)H(2)S-12) bridges between the boron atoms. An assembly (20) consisting of two diazaborolyl-ethynylene-phenylene-boryl units, [C(6)H(4)(NCy)(N')B-C[triple bond, length as m-dash]C-1,4-C(6)H(4)-BMes(2)] joined via a 1,4-phenylene unit at the nitrogen atoms (N') of the diazaborolyl units was also synthesised. The three push-pull systems, 3, 12 and 20, form salts on fluoride addition with the BMes(2) groups converted into (BMes(2)F)(-) anions. The molecular structures of 3, 12 and (NBu(4))(12·F) were elucidated by X-ray diffraction analyses. The borylated systems 3, 12 and 20 show intense blue luminescence in cyclohexane with quantum yields (Φ(fl)) of 0.99, 0.44 and 0.94, respectively, but weak blue-green luminescence in tetrahydrofuran (Φ(fl) = 0.02-0.05). The charge transfer nature of these transitions is supported by TD-DFT computations with the CAM-B3LYP functional. Addition of tetrabutylammonium fluoride to tetrahydrofuran solutions of 3 and 20 resulted in strong violet-blue luminescence with emission intensities up to 46 times more than the emission intensities observed prior to fluoride addition. Compounds 3 and 20 are demonstrated here as remarkable 'turn-on' fluoride sensors in tetrahydrofuran solutions.     

1,5-二芳基-3-(2-羟基-4,6-二甲氧基苯基)-2-吡唑啉的合成及氟离子荧光探针行为

设计合成了8个1,5-二芳基-3-(2-羟基-4,6-二甲氧基苯基)-2-吡唑啉化合物4a~4h. 它们的结构经由IR、1H NMR、MS和元素分析确认. 测定了它们的紫外光谱和荧光光谱, 研究了它们对氟离子的选择性识别作用, 发现化合物4a,4c和4d均可选择性地识别氟离子, 其中4a和4c作为识别氟离子的荧光探针, 受常见离子干扰较小, 选择性较高.     

共存牺牲剂对染料敏化TiO_2纳米晶体系电子传输的影响

采用卟啉染料敏化TiO2纳米晶在可见光条件下(λ390 nm)进行水分解制氢.考察了不同牺牲剂———甲醇(MeOH)、三乙醇胺(TEOA)及其混合物对体系析氢效率的影响.通过荧光猝灭及光电化学性能分析发现,激发态染料与TiO2之间的电子转移极大地受到添加的牺牲剂的影响,而体系的pH值对其影响不大.