Hydrogen bonds not only provide a structural scaffold to assemble donor and acceptor moieties of zinc porphyrin-quinone dyads but also control the photoinduced electron transfer to afford the long-lived charge-separated states

A series of zinc porphyrin-quinone linked dyads [ZnP-CONH-Q, ZnP-NHCO-Q, and ZnP-n-Q (n = 3, 6, 10)] were designed and synthesized to investigate the effects of hydrogen bonds which can not only provide a structural scaffold to assemble donor and acceptor moieties but also control the photoinduced electron-transfer process. In the case of ZnP-CONH-Q and ZnP-NHCO-Q, the hydrogen bond between the N-H proton and the carbonyl oxygen of Q results in the change in the reduction potential of Q. The strong hydrogen bond between the N-H proton and the carbonyl oxygen of Q*- in ZnP-CONH-Q*-,ZnP-NHCO-Q*-, and ZnP-n-Q*- (n = 3, 6, 10) generated by the chemical reduction has been confirmed by the ESR spectra, which exhibit hyperfine coupling constants in agreement those predicted by the density functional calculations. In the case of ZnP-n-Q (n = 3, 6, 10), on the other hand, the hydrogen bond between two amide groups provides a structural scaffold to assemble the donor (ZnP) and the acceptor (Q) moiety together with the hydrogen bond between the N-H proton and the carbonyl oxygen of Q, leading to attainment of the charge-separated state with a long lifetime up to a microsecond.     

钇配合物荧光猝灭法测定姜黄素含量

本文利用荧光光度法,吸收光谱法和共振光散射光谱法研究了钇(Y3+)-姜黄素(CU)-色氨酸(Trp)-十二烷基苯磺酸钠(SDBS)体系的荧光猝灭作用,研究发现,姜黄素能猝灭Y3+-Trp-SDBS体系的荧光强度。在最佳实验条件下,体系的荧光猝灭程度与CU的浓度在73.68～442.1,0.074～5.3μg.mL-1范围内呈良好的线性关系,其检出限为0.0185μg.mL-1,据此建立了姜黄素的测定方法,并且将其成功应用于实际样品的测定中。机理研究表明,Y3+-Trp-SDBS体系中的Y3+与姜黄素结合形成缔合物,拉近了Trp与姜黄素之间的距离,Trp通过分子间能量转移将所吸收能量转移到CU上,使体系的荧光猝灭。     

Synthesis and fluorescence properties of rare earth (Eu3+ and Gd3+) complexes with alpha-naphthylacetic acid and 1,10-phenanthroline

Rare earth binary complex Eu(NNA)3 (NNA, alpha-naphthylacetic acid), ternary complex Eu(NNA)3.phen (phen, 1,10-phenanthroline) and a series of dinuclear complexes with different mole ratios of Eu3+ to Gd3+ were synthesized. Many advanced approaches, such as element analysis, FTIR spectra, TG and DTA analysis, were used to determine the composition and structure of binary and ternary complex. Moreover, their fluorescence properties were studied by fluorescent spectra and lifetimes. The fluorescence spectra and decay curves of dinuclear complexes indicated that the fluorescence emission intensity was enhanced and the fluorescence lifetime was prolonged by Gd3+. The dinuclear complexes show the best properties when the mole ratio of Eu3+ to Gd3+ is 6:4. A new parameter Y, which was used to evaluate the effect of Gd3+, was introduced. In addition, the relationship of Y value and mole fraction of Gd3+ was analyzed by mathematical software. The results showed that Y value decreased by single exponential mode when the content of Gd3+ decreased.     

Yb/Er掺杂Y2O3纳米核壳颗粒的荧光性能及体内标定研究

为改善无机Y2O3上转换纳米粒子(UCNPs)的荧光性能,且同步实现其在生物体内的成像标定,通过共沉淀法及梯度合成工艺,制备出各组不同壳层厚度的Y2O3:Yb³⁺,Er³⁺@Y2O3:Yb³⁺ UCNPs。利用透射电子显微镜(TEM)扫描、X射线衍射(XRD)、上转换荧光(UCL)光谱、UCL寿命等对样品的形貌、结构及荧光性能进行了表征。结果表明：利用共沉淀法制得小尺寸Y2O3:Yb³⁺,Er³⁺@Y2O3:Yb³⁺纳米核壳颗粒,平均粒径范围在25.57~26.24 nm之间。通过调整Yb³⁺浓度和水浴时间优化合成工艺,获得高发射强度、长荧光寿命方案(80% Yb掺杂,8 h水浴)。高红绿比的荧光发射特征,决定其在小动物体内荧光标定检测时更宜采用红色信道。     

Synthesis and cofluorescence of Eu(Y) complexes with salicylic acid and o-phenanthroline

A series of dinuclear complexes of salicylic acid (HSal) and o-phenanthroline (Phen) with different molar ratios of Eu3+ to Y3+ have been synthesized. Their compositions are Eu(x)Y(1-x) (Sal)3(Phen) (x = 0 to approximately 1). Their UV spectra, IR spectra, and fluorescence spectra were studied. The UV spectra of the complexes reflect essentially absorption of the ligands for the fact that no obvious change of wavelength and band shape is found between the spectra of the complexes and that of the ligands except slight red shift. The IR absorption spectra indicate that salicylic acid is coordinated to the rare earth ions and chemical bonds are formed between rare earth ions and nitrogen atoms of o-phenanthroline. The fluorescence spectra of the complexes indicate that the fluorescence emission intensity of europium ion was enhanced by the addition of Y3+, which is referred to as cofluorescence. These facts show that not only the ligands but also the yttrium complex can transfer the absorbed energy to Eu3+ ion in the complexes. Formation of polynuclear complexes appears to be responsible for cofluorescence.     

Dy3+,Eu3+双掺单基质Ca9Y(PO4)7白色荧光粉的合成与发光性能

以具有多种格位的Ca9Y(PO4)7作为基质, 以Dy3+和Eu3+作为共激活剂, 利用高温固相法合成了一种单基质白光荧光粉. X射线衍射证实样品属于三方晶系菱面体结构, Dy3+和Eu3+在Ca9Y(PO4)7晶体中占据了Y3+ 的格位. 样品在365 nm紫外线激发下, 荧光光谱同时出现了Dy3+和Eu3+的特征发射, 且发光强度以及色度坐标随着Dy3+和Eu3+掺杂比率的变化而有规律变化, 所有样品的发射均处于白光区域. 利用近紫外芯片作为激发源, 单一基质白色荧光粉Ca9Y1-x-y(PO4)7: xDy3+, yEu3+可应用于白光发光二极管等领域.     

激光诱导荧光测定β-萘甲酰三氟丙酮合铕配合物的荧光寿命

本文采用激光诱导荧光的方法测定了九种L₄EuQH型β-二酮铕配合物的荧光寿命(其中Q表示胺的衍生物)。结果表明,对相同Q的配合物的6130Å,5910Å和5797Å三个荧光峰所测得的寿命均相同。不同的Q可能通过氢键作用对配合物的荧光寿命有一定影响。     

Visible luminescence spectroscopy of free-base and zinc phthalocyanines isolated in cryogenic matrices

The absorption, emission and excitation spectra of ZnPc and H(2)Pc trapped in Ne, N(2), Ar, Kr and Xe matrices have been recorded in the region of the Q states. A comparison of the matrix fluorescence spectra with Raman spectra recorded in KBr pellets reveals very strong similarities. This is entirely consistent with the selection rules and points to the occurrence of only fundamental vibrational transitions in the emission spectra. Based on this behaviour, the vibronic modes in emission have been assigned using results obtained recently on the ground state with large basis-set DFT calculations [Murray et al. PCCP, 12, 10406 (2010)]. Furthermore, the very strong mirror symmetry between excitation and emission has allowed these assignments to be extended to the excitation (absorption) bands. While this approach works well for ZnPc, coupling between the band origin of the S(2)(Q(Y)) state and vibrationally excited levels of S(1)(Q(X)), limits the range of its application in H(2)Pc. The Q(X)/Q(Y) state coupling is analysed from data obtained from site-selective excitation spectra, revealing pronounced matrix and site effects. From this analysis, the splitting of the Q(X) and Q(Y) states has been determined more accurately than in any previous attempts.     

1,2-邻苯二氧基二乙酸铕及掺杂L(L=La,Y,Yb,Nd)配合物的合成及荧光性质研究

在乙醇体系中,以氯化铕与1,2邻苯二氧基二乙酸和二苯甲酰甲烷反应合成了三元配合物Eu-BDDA-DBM以及弱荧光离子La3+,Y3-,Yb3-和Nd3+掺杂的铕配合物.通过红外、紫外-可见、热重、荧光光谱对配合物进行了表征.红外光谱表明,单一配合物和掺杂配合物具有相似的配位结构.荧光光谱表明,La3+和Nd3+离子掺杂可以大幅度提高的铕配合物的荧光强度,其中La3+掺杂荧光强度增强最明显.     

Fluorescence spectra of Tb3+-doped dual lanthanide oxyhalide powder phosphors

This short note presents the chemical preparation and recording of the fluorescence spectra of a new series of Tb³⁺-doped (La, Gd)OF, (La, Gd)OCl, (La, Y)OF and (La, Y)OCl powder phosphors. These phosphors have displayed green colour emission when irradiated with UV light. The measured fluorescence levels have been characterized by determining their stimulated emission cross-sections.     

Study on the co-luminescence system of Dy-Gd-1,6-bis(1'-phenyl-3'-methyl-5'-pyrazol-4'-one)hexanedionecetyltrimethylammonium bromide and its analytical application

Dy-1,6-bis(1'-phenyl-3'-methyl-5'-pyrazol-4'-one)hexanedione-cetyltrimethylammonium bromide (Dy-BPMPHD-CTMAB) ion association system has strong fluorescence intensity. In this system, some rare earth ions such as Gd3+, Y3+ and La3+ can exert a fluorescence enhancement effect, leading to a newly found co-luminescence system. From this, a rapid, simple and sensitive method was developed for the determination of trace amounts of Dy3+. The results indicate that the fluorescence intensity of the system is linearly related to the concentration of Dy3+ in the range 1.0 x 10(-7)-1.2 x 10(-5) mol L(-1) and the detection limit (S/N = 3) is 3.0 x 10(-8) mol L(-1). The luminescence mechanism of the system is discussed.     

稀土三元配合物粉末和凝胶共发光效应的光声光谱研究

合成了Eu(TTA)3·Phen和Eu0.8Y0.2(TTA)3·Phen固体配合物微晶粉末及其掺杂的SiO2凝胶样品.在300～800nm测定并解释了其光声光谱.在配体吸收处,Eu0.8Y0.2(TTA)3@Phen的光声强度低于Eu(TTA)3@Phen的光声强度;而对于配合物掺杂的凝胶样品,则情况相反.Y3+的引入改变了配合物的弛豫过程,且配合物在粉末和凝胶状态下,弛豫历程不尽相同.结合荧光光谱研究了标题化合物的发光特性,并建立了能量传递模型.     

A study on the photophysical properties of anthracene in zeolite

The photophysical behaviours of anthracene in zeolite Y were investigated using various steady state spectroscopic methods and a picosecond time-resolved fluorescence spectroscopic technique. A ¹²⁹Xe nuclear magnetic resonance (NMR) study shows that anthracene molecules can be optimally intercalated into the supercages of Na⁺- and Cu²⁺-exchanged zeolite Y at 570 and 520 K respectively. Anthracene introduced into the supercage of Na⁺-exchanged zeolite Y shows excimeric fluorescence with a lifetime of several nanoseconds, as well as monomeric fluorescence with a lifetime of 300 ps. The excimer forms immediately on absorption of a photon. Cu²⁺-exchanged zeolite Y with anthracene intercalation shows electron spin resonance (ESR) signals and absorption bands attributable to the stable, ground state anthracene cation radical, the Cu⁺ ion and the trapped electron in the copper ion cluster, indicating charge transfer from anthracene to the Cu²⁺ ion or copper ion cluster. The excitation energy of anthracene is quenched rapidly by the presence of copper ion.     

全反式维甲酸合钇(Ⅲ)配合物对DNA的切割和键合作用(英)

以紫外光谱、荧光光谱、粘度法和凝胶电泳方法研究了全反式维甲酸合钇(Ⅲ)配合物与DNA的作用。结果表明，该配合物能在生理条件下比配体和金属离子更有效地切割质粒DNA，体系离子强度和pH值的变化对配合物的切割活性有较大影响，自由基捕捉剂的加入不影响配合物的切割活性。该配合物对DNA的切割可能通过水解机理进行。该配合物可使DNA的粘度增加，使EB-DNA体系的荧光强度和DNA溶液的紫外吸收强度降低。据此推断，该配合物主要以嵌入方式与DNA作用。     

A direct imaging of amphiphilic catalysts assembled at the interface of emulsion droplets using fluorescence microscopy

An amphiphilic fluorescent catalyst Q9[EuW10O36] (Q = [(C18H37)2N+ (CH3)2]), assembled in the interface of emulsion systems, was directly imaged by fluorescence microscopy; the catalyst shows high selectivity and activity in the oxidation of alcohols using H2O2 as oxidant and the catalyst can be easily separated and recycled by demulsifying.     

具有生物活性的金属配合物的研究 II: 3,6-二(二甲氨基)-二苯并碘六环稀土乙二胺四乙酸配合物的合成, 性质及抗肿瘤活性

合成了十四种新的3,6-二(二甲氨基)-二苯并碘六环稀土乙二胺四乙酸(EDTA)配合物, 其化学式为[C17H20N2I][RE(EDTA)].xH2O(RE=Ce, x=2; Pr, x=3; Nd-Lu, Y,x=4). 利用热重-差热分析, X射线粉末衍射, 摩尔电导,红外及紫外光谱等对这些配合物进行了表征. 试验表明, 配合物对体外癌(L7712)细胞DNA合成的抑制率较其前体为高.     

2,7-萘二磺酸阴离子导向五元瓜环基超分子自组装体的制备及其荧光检测性能

通过引入2,7-萘二磺酸(2,7-NDA^2-)阴离子作为结构导向剂,与五元瓜环(Q[5])和过渡金属离子(Co²⁺、Ni²⁺、Zn²⁺、Cd²⁺)在水热条件下制备了4种新颖的Q[5]基超分子自组装体(Q[5]-SA),即{[M (H₂O)₄(Q[5])]·(NDA)}·xH₂O (M=Co (1)、Ni (2)、Zn (3))和{[Cd₂Cl₂(H₂O)₄(Q[5])]·(NDA)}·13H₂O (4)。单晶X射线衍射测试结果表明,自组装体1~3同构,其中Q[5]仅一端的部分端口羰基氧原子与金属离子配位形成简单配合物;而4中Q[5]的2个端口均与金属离子Cd²⁺配位形成了一维配位链。在自组装体1~4中,配体2,7-H₂NDA均全脱质子,形成2,7-NDA^2-阴离子平衡体系电荷,但均未能与金属离子配位,而在2,7-NDA^2-阴离子与Q[5]外壁之间的瓜环外壁作用下进一步形成三维超分子结构。此外,还研究了自组装体1和4的荧光传感性能,结果表明它们都能够作为抗生素诺氟沙星(NFX)的比率型荧光探针。     

Ab initio thermochemistry of the hydrogenation of hydrocarbon radicals using silicon-, germanium-, tin-, and lead-substituted methane and isobutane

A series of reactions of the type Y. + XH(4) --> YH + .XH(3) and Y'. + HX(CH(3))(3) --> Y'H + .X(CH(3))(3), where Y = H, CH(3); Y' = CH(3), C(CH(3))(3); and X = Si, Ge, Sn, Pb are studied using state-of-the-art ab initio electronic structure methods. Second-order M?ller-Plesset perturbation theory; the coupled-cluster singles, doubles, and perturbative triples method; and density functional theory are used with correlation-consistent basis sets (cc-pVNZ, where N = D, T, Q) and their pseudopotential analogs (cc-pVNZ-PP) to determine the transition-state geometries, activation barriers, and thermodynamic properties of these reactions. Trends in the barrier heights as a function of the group IVA atom (Si, Ge, Sn, and Pb) are examined. With respect to kinetics and thermodynamics, the use of a hydrogen attached to a group IVA element as a possible hydrogen donation tool in the mechanosynthesis of diamondoids appears feasible.     

1,4-二羟基蒽醌及其Y~(3+)配位聚合物与DNA相互作用研究

利用紫外-可见吸收光谱(UV-Vis)、核磁共振(1HNMR)、红外光谱(FTIR)研究了1,4-二羟基蒽醌(DHA)与Y3+的配位作用,结果表明Y3+与DHA能形成物质的量之比为1:1的一维链状配位聚合物Y-DHA.与DHA相比,Y-DHA在可见光区的吸收大幅增强,同时具有良好的水溶性.紫外-可见吸收光谱、荧光光谱及DNA熔链温度实验研究结果表明,Y-DHA与CTDNA可通过静电作用和沟槽结合的方式结合,而DHA与CTDNA的作用方式主要为沟槽结合.循环伏安法表明,Y-DHA的还原电位(-0.324VvsSCE)要高于DHA的还原电位(-0.387VvsSCE).无氧条件下,Y-DHA光损伤DNA的能力要明显高于DHA.     

Tetrahaloindate(III)-based ionic liquids in the coupling reaction of carbon dioxide and epoxides to generate cyclic carbonates: H-bonding and mechanistic studies

The microwave reactions of InX3 with [Q]Y produce a series of tetrahaloindate(III)-based ionic liquids (ILs) with a general formula of [Q][InX3Y] (Q = imidazolium, phosphonium, ammonium, and pyridinium; X = Cl, Br, I; Y = Cl, Br). The reaction of CO2 with a variety of epoxides has been examined in the presence of these ILs wherein tetrahaloindate(III)-based ILs are found to exhibit high catalytic activities and evidence is presented that supports the significant role of H-bonding interactions in the [Q][InX3Y]-catalyzed coupling reactions. The effects of various parameters such as temperature, pressure, and molar ratio of propylene oxide to catalyst have been investigated, and the plausible reaction mechanism based on the 1H and 13C NMR studies is presented for the formation of propylene carbonate.