N,N,N,N-tetradentate Macrocyclic Ligand Based Selective Fluorescent Sensor for Zinc (II)

N,N,N,N-tetradentate macrocyclic ligand (L) has been synthesized by the condensation of benzil and semicarbazide and characterized. On excitation by light of wavelength 350?nm, L exhibited a fluorescent peak at λ(max)?=?454?nm, which showed ca 6 times enhancement in intensity with a blue shift on interaction with Zn(2+). L has been found to act as a selective fluorescent sensor for zinc(2+) ion over a host of other metal ions such as- Cd(2+), Pb(2+), Hg(2+), Ca(2+), Fe(2+), Na(2+), Co(2+), Mn(2+), Cu(2+) and Ni(2+), in 1:1 CH(3)OH:H(2)O. A 1:1 complex formation between L and Zn(2+) was proved. The enhancement in the fluorescence could be explained on the basis of Photo induced electron transfer (PET) mechanism with log β?=?1.86.     

环糊精锌(Ⅱ)荧光试剂在水分析中的应用研究

合成高水溶性的锌()荧光试剂-修饰环糊精的N-(8-对氨基苯磺酰)胺基喹啉(HQAS-1-CD)。该试剂在水溶液中与Zn2+形成2:1配合物而使荧光增强,并且碱金属或碱土金属离子几乎不干扰Zn2+的荧光。利用此配位反应建立了一个荧光测定痕量锌的新方法,测定锌的线性范围为0—13μg/L,检出限0.57μg/L,方法成功的应用于矿泉水中痕量锌的测定。     

Highly Selective and Sensitive Chemosensor for Hg2+ Based on the Naphthalimide Fluorophore

A new OFF-ON fluorescent chemosensor (H1) composed of a naphthalimide fluorophore and a 6-[(quinolin-8-yloxy)methyl]pyridin-2-ylmethanamine receptor has been synthesized and characterized by infra-red, (1)H NMR, (13)C NMR and mass spectrometry. The developed chemosensor H1 exhibited good turn-on and reversible responses toward Hg(2+), with excellent selectivity and sensitivity, in a neutral buffered aqueous solution. Other common metal ions did not interfere with the fluorescence-enhancement response to Hg(2+). Furthermore, the chemosensor H1, at a concentration of 10?μM, showed a rapid and linear response toward Hg(2+) in the concentration range 0-10?μM. On addition of 10?μM Hg(2+), the fluorescence intensity of H1 was enhanced about 4-fold. The detection limit was calculated to be 63?nM. The association constant was 1.11?×?10(5)?M(-1). The fluorescence quantum yield and lifetime of H1/Hg(2+) were 0.42 and 3.83?ns, respectively.     

一个检测痕量汞离子的鱼精DNA修饰纳米金共振散射光谱法

在pH 7.0 Tris-HCl缓冲溶液及0.017 mol.L-1NaCl介质中,鲱鱼精DNA与10 nm的金纳米粒子形成较稳定的结合物使得金纳米粒子不聚集,体系的散射信号较弱。当有Hg2+存在时,DNA与Hg2+形成更稳定的DNA-Hg2+结合物,金纳米粒子聚集导致572 nm处的共振散射峰增强。在3.87μg.mL-1金纳米粒子-11.7μg.mL-1DNA-pH 7.0~17 mmol.L-1NaCl条件下,Hg2+浓度c在3.3~3 333.3 nmol.L-1范围内与572 nm处的共振散射强度增强值ΔI572 nm成良好线性关系,其回归方程、相关系数、检出限分别为ΔI572 nm=0.019c+5.0,0.999 1,2.5 nmol.L-1。该法用于水样分析,结果与冷原子吸收光谱法一致,相对标准偏差为5.1%。     

毛细管电泳电感耦合等离子体原子发射光谱法分析铁的形态

用毛细管电泳电感耦合等离子体原子发射光谱法研究了Fe2+-Fe3+在络合剂o-phen中,混合络合试剂o-phen和EDTA中的形态分离,以及游离态Fe2+-Fe3+的分离。考察了电压、缓冲液的pH值和络合剂浓度等对游离态铁形态分离的影响,获得了满意的分离条件。在分析过程中,阳离子、阴离子、以及络合试剂均不产生干扰,该方法优于毛细管电泳紫外-可见光谱法。     

硫氰酸铵-十二烷基二甲基苄基氯化铵-水体系浮选分离汞(Ⅱ)

研究了硫氰酸铵-十二烷基二甲基苄基氯化铵-水体系浮选分离汞(Ⅱ)的行为及其常见金属离子的分离条件。控制pH=5.0,当0.01mol/L硫氰酸铵溶液和0.01mol/L十二烷基二甲基苄基氯化铵(DDBAC)溶液的用量分别为0.30、0.50mL时,体系中形成的不溶于水的三元缔合物(DDBAC)2[Hg(SCN)4]可浮于水相上层形成界面清晰的液-固两相,分相过程中,Hg2+被定量浮选,而Zn2+,Cd2+,Mn2+,Ni2+,Co2+,Fe2+等离子在此条件下不被浮选,实现了Hg2+的定量分离。该方法对合成水样中微量Hg2+进行定量浮选分离测定,浮选率为96.0%—108.8%。     

Eu2+激活的硅酸锶材料的发光特性

采用高温固相法制备了Sr₃SiO₅ : Eu²⁺黄色发光材料,研究了Eu²⁺浓度及共激活剂等对材料发光性能的影响。结果显示,随Eu²⁺浓度的增大,Sr₃SiO₅ : Eu²⁺材料发射强度先增强后减弱,即存在浓度猝灭效应,根据Dexter理论,其浓度猝灭机理为电偶极-偶极相互作用。掺入共激活剂Yb、Tm均能提高材料的发射强度。利用InGaN管芯分别激发Sr_2.98Eu_0.01Tm_0.01SiO₅和Sr_2.98Eu_0.01Yb_0.01SiO₅材料,获得了很好的白光发射。     

Y3Al5O12:Ce3+,Cr3+和Y3Al5O12:Ce3+,pr3+,Cr3+荧光粉体系中的能量传递

通过在YAG:Ce3+和YAG:Ce3+,pr3+荧光粉体系中分别掺入Cr3+离子来提高蓝光管芯白光LED的显色指数.Cr3+离子的加入,增加了红光发射,这归因于Cr3+的2E-4 A2跃迁的零声子线和声子边带发光.Ce3+→Cr3+的能量传递是增强红光发射的重要方式,在YAG:Ce3+,Cr3+体系中,由发射光谱得到...     

自蔓延高温合成掺杂SrAl2O4稀土长余辉发光粉的研究

在600℃下用自蔓延高温法制备了SrAl2O4∶Eu2+0.012 5,RE3+0.012 5(RE3+=Ce3+,Pr3+,Nd3+,Tb3+,Dy3+),SrAl2O4∶Eu2+0.012 5,M0.012 5(M=Li+,Be2+,Cd2+,Mn2+,Cu2+,Ag+,Zn2+,pb2+),SrAl2O4∶Eu2...     

Structure of iron phosphate glasses modified by alkali and alkaline earth additions: neutron and x-ray diffraction studies

The structure of iron phosphate glasses modified by additions of K(2)O and BaO, with nominal molar compositions [(1 - x)(0.6P(2)O(5)-0.4Fe(2)O(3))]xMe(y)O, where x = 0-0.4 in increments of 0.1; Me=K or Ba; and y = 1 or 2, has been investigated using neutron diffraction and x-ray diffraction techniques. Fitted coordination numbers for P-O and Fe-O showed a notable change in the P-O(NBO) and P-O(BO) contributions at greater than 20 mol% modifier addition, with barium producing a markedly larger increase in P-O(NBO) contribution than potassium. Fitting of T(N)(r) and T(X)(r) provided average n(BaO) = 9 and n(KO) = 6. Iron occurs in a range of coordination sites in these glasses: ([6])Fe(2+), ([4])Fe(3+), ([5])Fe(3+) and ([6])Fe(3+). The partitioning between these sites gives average n(FeO) = 5.2-5.8, with barium-doped glasses exhibiting higher average n(FeO) than potassium-doped glasses. The stronger depolymerizing effect of Ba(2+) than K(+) on the phosphate network, coupled with its greater ionic charge and higher Me-O, Fe-O and O···O coordination numbers, explain previously observed divergences in physical properties between the barium-doped and the potassium-doped glasses.     

d^10组态金属离子与邻菲罗啉衍生物配位反应的^1H NMR研究

通过研究ｄ＾１０组态金属离子Ｚｎ＾２＋，Ｃｄ＾２＋，Ｈｇ＾２＋与邻菲罗啉及其衍生物发生配位时配体的＾１Ｈ ＮＭＲ谱的变化，对配离子的种类进行了讨论，给出了配离子中配键稳定性的比较，提出了一种通过实验直接研究溶液中的ｄ＾１０组态离子为中心离子的配合物的方法。     

Laser spectroscopy of jet－cooled CuF in visible region

The laser-induced fluorescence excitation spectra of jet-cooled CuF have been recorded in the range of 19000－21470cm^{-1}, in which the CuF radicals were produced by the reaction of SF_6 with copper atoms from a dc discharge-sputtering source under supersonic jet conditions. Eight observed vibronic transition bands have been assigned as the transition from the ground state X(^1Σ^+) to B(^1Σ^+), C(^1Π) and an unreported upper state. The rotational structure of all observed bands has been analysed at the estimated rotational temperature 80K. We determined the newly observed band to be the (^1Π, v=1)－X(^1Σ^+v=0) transition according to the character of the rotational structure and the isotopic shift analysis. In addition, the lifetimes of the states involved in these bands were measured.     

Energieniveaus und Gammaübergänge in Dy 164

The neutron capture Gamma ray spectrum of Dy 164 was measured with the curved crystal spectrometer at the DR-3 reactor at Risø. A level scheme was constructed from the energies (30 keV?1 MeV) and the intensities of the detected lines. The states obtained are: the groundstate rotational band with the levels at 73.392 (0.2+), 242.230 (0.4+), and 501.32 keV (0.6+), the Gamma vibrational levels 761.80 (2.2+), 828.19 (2.3 +), 915.98 (2.4+) and 1024.63 keV (2.5+) and a band withK=2?having the energies 976.88 (2.2?), 1039.30 (2.3-), 1122.76 (2.4?) and 1225.15 keV (2.5?). The precisely determined energies are compared with the collective model. The intensities of the transitions agree with the branching ratios expected from this model.     

Spectroscopic characteristics of Yb^3＋：LiLa（WO4）2 crystal

The spectroscopic characterization and fluorescence dynamics of Yb^3＋：LiLa（WO4）2 crystal are investigated. The Yb^3＋：LiLa（W04）2 crystal exhibits a broad absorption and emission spectral bands, large absorption and emission cross sections, and moderate fluorescence lifetime. Blue light emission around 480 nm is observed at 10 K and is demonstrated through cooperative upconversion from the deexcitation of excited Yb^3＋-Yb^3＋ pairs.     

CaMoO_4:Tb~(3+)发光材料的制备和发光性质的研究

用共沉淀法制备了样品CaMoO_4:Tb~(3+)的前驱物,经TG-DTA测试表明:样品在850℃时有能量吸收峰,即达到样品反应的活化点。XRD谱图分析显示,焙烧后样品CaMoO_4:Tb~(3+)为CaMoO_4的白钨矿结构,但峰位发生了右移,说明晶体内部产生了微小的晶体缺陷,推测该缺陷可能是由晶胞内2个Tb~(3+)取代了3个Ca~(2+)形成空穴而引发的。通过对激发谱图的测试发现,此种缺陷结构有利于使MoO_4~(2-)发射特征峰(488 nm)的能量有效地传递给Tb~(3+),使Tb~(3+)的4f电子发生跃迁,特别使Tb~(3+)的~7F_6→~5D_4(488 nm)电子跃迁大大加强,因而在样品CaMoO_4:Tb~(3+)的发射谱图(λ_(ex)=488 nm)中,自激活荧光体MoO_4~(2-)的发射强度被大大减弱,而Tb~(3+)的~5D_4→~7F_5(544 nm)跃迁的绿光发光强度被大大增强,使该材料成为有潜在应用价值的发光材料。     

稀土钕-丙烯酸-草酸配合物的合成、表征及荧光性能

合成了钕-草酸-丙烯酸三元固体配合物。利用元素分析、红外光谱(FT-IR)、紫外-可见光谱(UV-Vis)、热重分析(TGA)和荧光光谱等手段研究了配合物的结构和性质。结果表明配合物的组成为[Nd(OOC—COO)(CH2CH—COO)].3H2O,热分析结果表明该配合物具有较好的热稳定性。荧光光谱表明配合物都具有较好的荧光特性,且发射谱线很窄,主发射峰为钕离子的4G5/2 2G7/2-4I9/2跃迁,表明合成的新型稀土配合物可用作光致发光材料。     

Tm~(3+)/Yb~(3+)∶LaF_3纳米体系中掺杂Yb~(3+)离子对Tm~(3+)离子荧光发射的影响

为研究Yb~(3+)离子浓度变化对Tm~(3+)离子在蓝色波段荧光强度的影响,以NaF和La(NO_3)_3为原料,采用水热法制备了Tm~(3+)和Yb~(3+)共掺的Tm~(3+)/ Yb~(3+)∶LaF_3纳米颗粒.用X射线衍射对LaF_3纳米颗粒进行表征的结果显示,纳米晶体结构呈六方相.透射电镜的观测结果显示,纳米颗粒样品大小均匀、分散性良好.在波长为800 nm的激光激发下,观测到了上转换蓝光发射,其中包括波长为474 nm和479 nm的较强的荧光辐射(相应的跃迁为~1G_4→~3H_6)和波长位于450 nm的强度较弱的荧光发射(相应的跃迁为~1D_2→~3F_4).通过观测不同Yb~(3+)离子浓度条件下共掺Tm~(3+)/Yb~(3+)∶LaF_3样品的荧光光谱,研究了Yb~(3+)离子掺杂浓度对于Tm~(3+)离子的荧光发射的影响,并探讨了产生这种现象的原因.研究结果显示,对于~1G_4→~3H_6跃迁产生的荧光发射(474 nm),当Yb~(3+)离子浓度增大时,反向能量传递速率的增加导致了荧光强度的增大.然而,当Yb~(3+)离子浓度增大到一定程度时,Yb~(3+)离子激发态能级寿命的减少将引发荧光强度的下降.相比较而言,Yb~(3+)离子的浓度的变化对于~1D_2→~3F_4跃迁产生的位于450 nm处荧光强度的影响较弱.     

纳米棒状长余辉材料BaAl_2O_4:Eu~(2+),Dy~(3+)的制备与发光性能

利用硝酸铝、硝酸钡、尿素为原料,以一定比例H_2O/正丁醇及H_2O/正丁醇/SBS的混合液作传递压力的介质,进行反应,然后将得到的前驱体在还原气氛下高温煅烧,得到亮度高,余辉时间长的BaAl_2O_4:Eu~(2+),Dy~(3+)纳米棒状长余辉发光材料。TEM和SEM测试表明高温煅烧后得到的BaAl_2O_4:Eu~(2+),Dy~(3+)为棒状结构,其激发光谱和发射光谱均为宽带,主发射峰分别为498 nm,是典型的Eu~(2+)5d→4f跃迁。该方法的特点在于:采用水热法合成的BaAl_2O_4:Eu~(2+),Dy~(3+)长余辉发光材料一般需经过高温煅烧,容易结块,而在合成制得的产品经1 300℃高温煅烧后仍呈现分散性良好的棒状结构,不需球磨,且发光性能良好,可直接应用。同时将2种不同的实验条件进行比较,发现在不使用表面活性剂的条件下依然可得到分散性良好的棒状BaAl_2O_4:Eu~(2+),Dy~(3+)长余辉发光材料。该制备方法有望在其他铝酸盐和硅酸盐系长余辉发光材料的制备中得到应用。     

水溶液中甘氨酰替亮氨酸与Ho(ClO43和Yb(ClO43相互作用的NMR研究

本文用¹³C NMR方法研究了水溶液中三价顺磁性稀土离子Ho³⁺和Yb³⁺与二肽甘氨酰替亮氨酸之间的相互作用。对稀土诱导位移中的接触位移和偶极位移进行了分离。实验表明,与羧基相连的碳核所受的接触作用很大,因此不能把镱诱导的位移直接用于肽的构象分析。在水溶液中,肽通过羧基与稀土离子配位,在弱酸性条件下肽键和氨基均不参与配位。根据结构因子确定了肽在溶液中的构象,结果表明,分子片段C1-C2-C5-C6,C2-N-C3-C4和C2-C5-C6-C8为反式,而C2-C5-C6-C7和C1-C2-N-C3成旁式。     

A Highly Efficient Turn-On Fluorescent Sensor for Determination of Water in Organic Solvents

2, 3 biphenyl quinoxaline 6-amine is a fluorescent compound in some organic solvents with an excitation wavelength at 435?nm and a fluorescence emission at 518?nm. The fluorescence intensity of 2, 3 biphenyl quinoxaline 6-amine is significantly reduced in the presence of bis-(2, 4, 6-trichlorophenyl) oxalate (TCPO) and Zn(2+) due to the nonfluorescent complex formation. The low stability of the complex in presence of trace amount of water results in decomposing complex, thereby recovering the photoluminescence of 2, 3 biphenyl quinoxaline 6-amine. Based on this fact, a turn-on fluorescence photoluminescence sensor for determination of water content in organic solvents was introduced for the first time.The fluorescence intensity of 2, 3 biphenyl quinoxaline 6-amine as a function of water concentration was used as a simple, sensitive and rapid method for determining trace amount of water in some organic solvents such as ethanol and methanol. The obtained results showed a good linear relationship between fluorescence intensity and the water content with a dynamic range of 0.0094 -1(v/v%), related coefficient of 0.9922 and limit of detection of 0.0026(v/v%). %).