Mechanically induced chemiluminescence in the dispiro(adamantane-1,2-dioxetane)—Eu(fod)3 system

Luminescence accompanying an impact mechanical treatment of solid particles of the complex of Eu(fod)₃ (fod is 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione) with dispiro(adamantane-1,2-dioxetane) (1) was discovered and studied. The luminescence has a complex structure, and its spectrum belongs to the excited Eu^III ions. The emission of light is observed only in a mechanical mixture of the Eu(fod)₃ with dioxetane1 and in their cocrystallized form, but not in the case of the components taken separately. The mechanism by which the impacts cause the luminescence is considered. It was shown that the luminescence is not triboluminescence, but is chemiluminescence induced by the decomposition of compound1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1159–1162, May, 1996.     

Chemiluminescence and catalysis of the decomposition of dispiro(diadamantane-1,2-dioxetane) in solutions of lanthanide perchlorates

Decomposition of dispiro(diadamantane-1,2-dioxetane) (1) in acetonitrile solutions of Eu^III, Gd^III, Tb^III, Pr^III, and Ce^III perchlorates was studied by tile chemiluminescence method. The rate constants of decomposition of1 in complexes of composition1 · Ln^III and stability constants of these complexes, as well as activation parameters of the decomposition of1 and thermodynamic parameters of the complexation were determined. A correlation between the thermodynamic parameters of complexation and ionic radii of Ln^III was found.Translated fromIzvestiya Nauk. Seriya Khimicheskaya, No. 10, pp. 2479–2483, October, 1996.     

Effect of 4f-shell excitation of Eu(fod)3 on its complex formation with alicyclic ketones

The complex formation of alicyclic ketones, viz., camphor, cyclohexanone, menthone, and cytisine, with the Eu(fod)₃ chelate (fod is 7,7-dimethyl-1,1,1,2,2,3,3-heptafluorooctane-4,5-dione) in the ground and excited states was studied by chemiluminescence and kinetic luminescence spectroscopy, respectively. The stability constants and thermodynamic parameters of complex formation were determined. An increase in the stability of the electron-excited complexes [Eu(fod)₃*·Ketone] is explained by the enhancement of the acceptor ability of the Eu³⁺ chelate due to an increase in the fraction of the covalent component caused by the involvement of 4f-orbitals. The results obtained give direct evidence for the effect of the 4f-shell excitation of Eu(fod)₃ on complex formation due to the involvement of f-electrons in the chemical bonds.     

Chemiluminescence and catalysis of decomposition of dispiro(diadamantane-1,2-dioxetane) in solutions of lanthanide perchlorates

Chemiluminescence (CL) accompanying the decomposition of dispiro(diadamantane-1,2-dioxetane) (1) in acetonitrile solutions of Eu^III, Gd^III, Tb^III, Pr^III, and Ce^III perchlorates was studied. In the presence of Eu^III, Tb^III, and Pr^III ions, the chemiluminescence spectra contain the luminescence bands of these ions. In the cases of Gd^III and Ce^III, the chemiluminescence is caused by deactivation of singlet-excited adamantanone (2). The excitation of the lanthanide ion depends on the existence of suitable energy levels at which intracomplex excitation transfer from the³n,π^* of ketone is possible. Chemiluminescence of1 increases in solutions of Eu^III and Tb^III. The yields of CL and excitation of the lanthanide ions in the decomposition of1 in the1·Eu^III and1\Tb^III complexes were determined: φ_Eu · =0.013 ± 0.003 and φ_Tb · =0.08±0.02. The fact that the efficiency for the population of the⁵D₄-level of Tb^III is higher than that for the⁵D₁ and⁵D₀-levels of Eu^III is related to the difference in the energy gap between the triplet level of2 and the excited levels of the lanthanides. For Part I, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 730–735, April, 1997.     

Eu(fod)(3) binding on the (1)H-NMR spectra of some benzo[3n]crown-n and dibenzo[3n+2]crown-n

The complexing of Eu(fod)₃ with macrocyclic ethers, benzo[15]crown-5, benzo[12]crown-4, dibenzo[20]crown-6, dibenzo[23]crown-7 and dibenzo[26]crown-8 was observed on their ¹H-NMR spectra and the selective binding constants at 400 MHz and 305 K in CDCl₃ were reported. The Eu(fod)₃ interaction displayed the selective binding role of oxygen on macrocyclic, H₂COCH₂, backbones with o- or m-dioxyphenyl groups referring the ¹H chemical shifts. The estimated equilibrium constants, K_a of 1:1 ratio of interactions were in accordance with the Eu³⁺ ionic radii to bind the oxygen sites depending on the macrocyclic size and conformation of the ethers. The minimum lanthanide-macrocyclic ether distance displayed the maximum stability so that benzo[3n]crown-n (n=4, 5) group was found to bind the Eu(fod)₃ moderately whilst dibenzo[3n+2]crown-n (n=6-8) oligomer chemical shifts were induced largely since the such Eu³⁺ complexes are more stable with larger ethyleneoxy groups.     

The chemiluminescence of dispiro(1,2-dioxetane-diadamantane) sorbed on silipore activated by a phenanthroline complex of Eu(iii)

The thermal decomposition of dispiro(1,2-dioxetane-diadamantane) (1) sorbed on silipore containing EuCl₃ ando-phenanthroline was investigated. The observed chemiluminescence is caused by radiative deactivation of EU^*(iii) formed according to an energy transfer mechanism. Chemiluminescence decay in the course of the decomposition of1 is exponential with the rate constantk. The activation parameters of the decomposition of1 sorbed on silipore were determined from the temperature dependence ofk. These parameters are independent of the Eu(iii) content. A kinetic compensating effect was found: the dependence of logA onE _a as a function of the content of1. The mechanism of the compensating effect is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 447–451, March, 1995.     

NMR位移试剂Eu(fod)~4^-对锍盐^1H和^1^3C NMR的影响

合成了八种新的四氟硼酸二甲基苯基锍，用元素分析和核磁共振对其结构进行了表征。研究了以CDCl~3为溶剂，NMR位移试剂Eu(fod)~4^-对所合成锍盐的^1H和^1^3C NMR的影响。结果表明，Eu(fod)~4^-是一个对锍盐非常有效的位移试剂，且Eu(fod)~4^-对二甲基苯基锍盐之甲基的^1H和^1^3C NMR的位移呈线性关系。     

C60 fullerene, as ultraefficient quencher of singlet-excited adamantanone generated in photo-and chemiexcitation

Quenching of the fluorescence of Ad=O and its singlet-exited state (¹Ad=O*) generated in chemiluminescent reaction of adamantylideneadamantane-1,2-dioxetane (AdOOAd) termolysis by C₆₀ fullerene was detected and investigated. The “quenching efficiency-C₆₀ concentration” plots obtained from the decrease in the fluorescence and chemiluminescence intensities obey the Stern-Volmer law. The bimolecular rate constants (k _bim) were determined and the overlap integrals of the Ad=O fluorescence spectra with the C₆₀ absorption spectra (∫ _Ov) were calculated. Based on the nonconstant k _bim/∫_Ov ratios for different singlet-exited energy donors obtained for the ¹PAH*-C₆₀ systems (PAH are polycyclic aromatic hydrocarbons) and ¹Ad=O*-C₆₀, a conclusion is drawn that quenching of ¹Ad=O* by C₆₀ fullerene is a result of inductive-resonant singlet-singlet (major contribution) and exchange-resonant singlet-triplet (minor contribution) energy transfer. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1044–1046, May, 2007.     

链状Eu(BO_2)_3的合成与发光性能研究

采用固相反应合成出链状结构的稀土硼酸盐Eu(BO2)3发光材料。分别利用XRD、TEM、SAED、EDS和PL等测试技术对产物进行了研究,结果表明:链状结构的Eu(BO2)3属于单斜晶系,空间群为I2/a,直径约10～15nm,长度达几个微米,探讨了链状Eu(BO2)3的生长机理。在395nm紫外光激发下,Eu(BO2)3能发出Eu3+的特征红色荧光,发射主峰位于591nm,归属于5D0→7F1磁偶极跃迁。     

Eu(DBM)3纳米微晶的低频喇曼光谱

The fractal property and low frequency Raman scattering of Eu(DBM)3 nanosized microcrystals were investigated. The influence of the fractal structure of Eu(DBM)3 non-crystalline solids on low frequency scattering was studied. It was found that vibrational excitations on the fractal are localized and can be described in terms of fractions. It was shown that reduced Raman scattering intensity is of a power law dependence of the vibrational frequencies for all samples. The fractal and spectral dimension were also determined, we found that our experimental value was in fair agreement with the theoretical one.     

The thermal decomposition of (NH4)[VO(O2)2(NH3)]

The compound, (NH₄)[VO(O₂)₂(NH₃)], thermally decomposes to ammonium metavanadate, which then decomposes to vanadium pentoxide. Using a heating rate of 5 deg·min^–1, the first decomposition step occurs between 74° and 102°C. The transformation degree dependence of the activation energy (-E) is shown to follow a decreasing convex form, indicating that the first decomposition step is a complex reaction with a change in the limiting stage of the reaction. Infrared spectra indicated that the decomposition proceeds via the gradual reduction of the ratio of the (NH₄)₂O to V₂O₅ units from the original 11 ratio in ammonium metavanadate, which may be written as (NH₄)₂O·V₂O₅, to V₂O₅.The assistance of Professor A. M. Heyns (University of Pretoria) and Professor K. L. Range (University of Regensburg) is gratefully acknowledged as well as the financial assistance of the University of Pretoria and the FRD.     

Zur Synthese von (±)-cis-1,2-Epoxy-3-oxo-alkyl-phosphonsäureestern—Phosphonomycinanaloga

Treatment of dialkyl-3-oxo-1-alkenylphosphonates1 with OsO₄-H₂O₂ affords the (±)-threo-glycols2, which were characterised as their corresponding diacetates3. The derivatives2 were transformed into the mono-(tert-butyl-dimethylsilylether)-compounds4 and5. Subsequent treatment withp-toluene-sulfonyl chloride yields6 and7, which can be converted to (±)-cis-1,2-epoxy-3-oxoalkylphosphonates8 with tetrabutylammonium fluoride (TBAF). Sometimes thetrans-derivatives9 can be found just as the tosyloxyphosphonates11 and12 as by-products. In two cases the 1,2-dicarbonyl compounds10 were obtained.

Herrn Kollegen Prof. Dr.E. Ziegler zum 70. Geburtstag gewidmet.     

On the reduction of Cr3+ during the thermal decomposition of fluorochromates(III) with nitrogen containing cations

The thermal decomposition of [CO(NH₂)₂H]CrF₆·H₂O, (C₃N₆H₈)CrF₅·H₂O and the solid state reaction of CrF₃ and melamine are investigated under non-reciprocal quasi-static conditions and compared with the thermal behaviour of other fluorochromates(III) ([Cr(NH₃)₆]CrF₆, (NH₄)₃CrF and [C(NH₂)₃]₃CrF₆). The comparison of the results shows that the amount of chromium(II) in the final product is determined by the thermal stability and consequently by the decomposition temperature of the intermediates. Neither bonding properties in the starting materials nor the absolute amount of generated NH₃ influence the composition of the final product.     

Determination of NH(3) gas by combination of nanosized LaCoO(3) converter with chemiluminescence detector

Combination of a novel NH₃ converter based on nanosized materials with chemiluminescence (CL) detector for the determination of NH₃ gas was demonstrated in this paper. NH₃ gas is oxidized on different nanosized catalysts to produce NO_x, which can react with luminol to generate CL emission. Eight nanosized materials were investigated as catalyst, and CL was detected from seven of them. The nanosized LaCoO₃ was chosen as the catalyst for preparing the converter because of its higher activity than others. Under the optimized conditions, the linear range of CL intensity versus concentration of NH₃ gas is 0.04-10 ppm (r=0.9951, n=14) with the detection limit of 0.014 ppm. The method offers advantages of long lifetime of the converter, fast response and high selectivity to NH₃. There was no response while the foreign substances, such as hydrogen, oxygen, nitrogen, formaldehyde, acetone and gasoline passing through the CL detection system, and the interference of CCl₄, ethanol, ethylene and toluene was insignificant.     

Determination of itopride hydrochloride by high-performance liquid chromatography with Ru(bpy)3 electrogenerated chemiluminescence detection

In this work, a stable electrogenerated chemiluminescence (ECL) detector was developed. The detector was prepared by packing cation-exchanged resin particles in a glass tube, followed by inserting Pt wires (working electrode) in this tube and sealing. The leakage of Ru(bpy)₃²⁺ can be compensated by adding a small amount of Ru(bpy)₃²⁺ into solution phase. Coupled with high-performance liquid chromatography separation, the detector has been used for determination of itopride hydrochloride in human serum. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of itopride hydrochloride in the range of 1.0 × 10⁻⁸ g mL⁻¹ to 1.0 × 10⁻⁶ g mL⁻¹ and the detection limit was 3 × 10⁻⁹ g mL⁻¹ (S/N = 3). The as-prepared ECL detector displayed good sensitivity and stability.     

静电纺丝制备Eu(BA)3phen/PANI/PVP光电双功能复合纳米纤维及其性能

采用静电纺丝技术将聚苯胺(PANI)和稀土配合物Eu(BA)3phen掺杂到高分子材料聚乙烯吡咯烷酮(PVP)中, 制备出新型的具有光电双功能的Eu(BA)3phen/PANI/PVP复合纳米纤维. 采用扫描电子显微镜、 X射线能量色散谱仪、 荧光光谱仪及宽频介电松弛谱仪对样品进行了表征. 实验结果表明, 复合纳米纤维直径为(270±31) nm. 在275 nm紫外光激发下, Eu(BA)3phen/PANI/PVP复合纳米纤维发射出主峰位于580, 594和617 nm的红光, 对应于Eu3+的 5D0→7F0, 5D0→7F1和5D0→7F2跃迁. 当m[Eu(BA)3phen]:m(PANI):m(PVP)=15:10:100 时, 复合纳米纤维的荧光发射最强. 复合纤维的电导率随PANI含量的增大而升高. 在m(PANI):m(PVP)=50:100时, 其电导率在高频(106 Hz)下达到1.5×10-6 S/cm.     

Kinetics of the thermal decomposition of [Co(NH3)6]2(C2O4)3·4H2O

The thermal decomposition of [Co(NH₃)₆]₂(C₂O₄)₃·4H₂O was studied under isothermal conditions in flowing air and argon. Dissociation of the above complex occurs in three stages. The kinetics of the particular stages thermal decomposition have been evaluated. The R_N and/or A_M models were selected as those best fitting the experimental TG curves. The activation energies,E, and lnA were calculated with a conventional procedure and by a new method suggested by Kogaet al. [10, 11]. Comparison of the results have showed that the Arrhenius parameters values estimated by the use of both methods are very close. The calculated activation energies were in air: 96 kJ mol^–1 (R_1.575, stage I); 101 kJ mol^–1 (Ain1.725 stage II); 185 kJ mol^–1 (A _2.9, stage III) and in argon: 66 kJ mol^–1 (A _1.25, stage I); 87 kJ mol^–1 (A _1.825, stage II); 133 kJ mol^–1 (A _2.525, stage III).     

Electrogenerated chemiluminescence biosensor based on Ru(bpy)3(2+) and dehydrogenase immobilized in sol-gel/chitosan/poly(sodium 4-styrene sulfonate) composite material

A new electrogenerated chemiluminescence biosensor was fabricated by immobilizing ECL reagent Ru(bpy)₃²⁺ and alcohol dehydrogenase in sol-gel/chitosan/poly(sodium 4-styrene sulfonate) (PSS) organically modified composite material. The component PSS was used to immobilize ECL reagent Ru(bpy)₃²⁺ by ion-exchange, while the addition of chitosan was to prevent the cracking of conventional sol-gel-derived glasses and provide biocompatible microenvironment for alcohol dehydrogenase. Such biosensor combined enzymatic selectivity with the sensitivity of ECL detection for quantification of enzyme substrate and it was much simpler than previous double-layer design. The detection limit was 9.3 × 10⁻⁶ M for alcohol (S/N = 3) with a linear range from 2.79 × 10⁻⁵ to 5.78 × 10⁻² M. With ECL detection, the biosensor exhibited wide linear range, high sensitivity and good stability.