Kinetics of O2(a1Deltag) and I(2P1/2) in the photochemistry of N2O/I2 mixtures

The recent demonstration of a discharge-driven oxygen-iodine laser has generated renewed interest in the kinetics of iodine interacting with electronically excited O2 and atomic O. Kinetic measurements that are of relevance to the laser have been carried out using 193 nm pulsed laser photolysis of N2O/I2/CO2 mixtures. Singlet oxygen was generated in this system by the reaction O(1D)+N2O-->O2(a1Deltag, X3Sigma-g)+N2. The fraction of electronically excited O2 produced by this channel was shown to be >0.9. The secondary photochemistry of the N2O/I2/CO2 system was characterized by monitoring the time histories of I(2P1/2), I2, IO, and O2(a). Kinetic modeling of these data was used to determine the rate constant for the deactivation of I(2P1/2) by O(3P) (k=(1.2+/-0.1)x10(-11) cm3 s(-1)). Quenching of I(2P1/2) by O(3P) is suppressed in the discharge-driven laser by using NO2 to scavenge the O atoms. The reaction O(3P)+NO2-->O2+NO is sufficiently exothermic for the production of O2(a), and it has been speculated that this channel may be significant in the laser excitation kinetics. Photolysis of NO2 was used to probe this reaction. O2(a) was not detected, and an upper bound of <0.1 for its production in the reaction of O(3P) or O(1D) with NO2 was established.     

Structural,surface, optical,and antimicrobial characterization of I2/Polymethyl methacrylate and CuS/I2/polymethyl methacrylate thin films

In this study, I₂/PMMA and CuS/I₂/PMMA thin films were produced by Chemical Bath Deposition (CBD) on polymethyl methacrylate (PMMA) substrates, and their physicochemical and antimicrobial properties were analyzed. The film's surface tensions were characterized by KSV instruments, and the surface tensions for plain PMMA, I₂/PMMA, and CuS/I₂/PMMA thin films were 30.27, 28.77, and 31.86 mN/m, respectively. The I₂ and CuS/I₂ structures in the XRD patterns are amorphous. After coating CuS, the long rod-like extension structures are formed; spherical shapes form some agglomeration in some regions to SEM images. Chemical analysis was performed with an EDX spectrometer attached to SEM. The thicknesses and surface roughnesses of I₂/PMMA and CuS/I₂/PMMA thin films were determined to be 50.34 nm, 1126 nm; 62.03 nm and 204.99 nm via AFM, respectively. The optical spectra of the films were recorded in the range of 300–1100 nm with a UV-VIS spectrophotometer. The antibacterial and antifungal properties of I₂ and CuS coating were evaluated against facultative gram-negative E. Coli and C. Albicans. The coated films exhibited excellent antimicrobial performance.     

Solvent extraction of Tl/I/ with 2-mercaptobenzothiazole into chloroform

The extraction of Tl/I/ with 2-mercaptobenzothiazole into chloroform has been studied. The effect of various parameters on the extraction coefficient value has been evaluated. The stoichiometry of the extracted species obtained from the substoichiometric extraction was found to be 11. This war further supported by the slope ratio method. Decontamination factors of a number of elements in the substoichiometric extraction of Tl/I/ were also obtained.     

Solvent extraction of silver/I/ with 2-mercaptobenzothiazole into chloroform

A rapid and selective method for the extraction of Ag/I/ with 2-mercaptobenzothiazole/2-HMBT/ into chloroform has been developed. The effect of various parameters on the extraction coefficient of Ag/I/ such as pH, time of equilibration, solvents, anion interferences, cation interference and stoichiometry of the metal to reagent have been established.     

Quenching of I (2P1/2) by halogen cyanides

Relaxation rate constants for the collisional deactivation of I (²P_1/2) by halogen cyanides were measured by time resolved atomic absorption. The values obtained were (1.2 ± 0.1) × 10^?15, (5.2 ± 0.7) × 10^?15, and (2.6 ± 0.4) × 10^?14 cm³ molecule^?1 s^?1 for ClCN, BrCN, and ICN, respectively. Quenching efficiencies are discussed in view of the stability of linear molecules to form the transient complex as well as the similarities assumed between halogen cyanides and interhalogen diatomic molecules.     

Tensor polarizabilities of the (nd+(n+1)s)3 2 D 3/2,5/2 levels in Sc I,Y I,La I and Lu I

A technique based on the detection of nonlinear level-crossing resonances in parallel electric and magnetic fields has been extended to the study of the Stark splittings in the hyperfine levels of the ground multiplets (nd+(n+1)s)^{3 2} D _3/2,5/2 in Sc I, Y I, La I, and Lu I. Values of the tensor polarizabilities of thend electrons were evaluated from the experimental results. The variation of the tensor polarizabilities of thend electrons in the configurations under study is discussed. Trends of the polarizabilities in different configurations are compared. The ratio between the electric quadrupole constant and the tensor polarizabilities is constant in La and different in Lu, which is caused by a breakdown of the central field model.     

Hydrogenolysis of Lignin Catalyzed by NaBH4/I2

从麦草碱法制浆黑液中提取木质素,精制后,以苯乙酮为木质素的模型化合物,对催化剂组成及溶剂进行了考察.在此基础上,以NaBH4/I2为催化剂,无水乙醇为溶剂,对木质素进行加氢还原裂解反应研究.考察了温度和时间对木质素催化加氢效果的影响,采用红外光谱（FTIR）、元素分析及凝胶渗透色谱分析（GPC）,表征木质素反应前后结构的变化.凝胶渗透色谱分析表明,加氢还原后木质素的分子量明显降低.采用自动电位滴定法测定反应前后木质素中总羟基含量,反应后木质素中总羟基含量为10.19%.得到了NaBH4/I2催化木质素加氢还原反应的最优条件：以1,2-二氯乙烷和乙醇（2∶1,v/v）作溶剂,m（NaBH4）∶m（I2）=1∶1,温度175℃,反应时间15 h.     

Deactivation of I(52P1/2) by CF3I,CH3I,C2H5I,and CH4

The technique of laser photolysis of alkyl and perfluoroalkyl iodides at 266 nm followed by time-resolved detection of the 1.3-μm emission from I^*(²P_1/2) has been used to measure the rate constants for deactivation of I^* by CH₃I, C₂H₅I, CF₃I, and CH₄. The recommended values are (2.76± 0.22) × 10^?13, (2.85 ± 0.40) × 10^?13, (3.5 ± 0.5) × 10^?17, and (7.52 ± 0.12) × 10^?14, respectively, in units of cm³ molecule^?1 S^?1.     

Thermochemische Untersuchungen zum System Bi/Se/O. I. Das Phasendreieck Bi2Se3/Bi2O2Se/Se

Thermochemical Investigation on the System Bi/Se/O. I The Phase Triangle Bi₂Se₃/Bi₂O₂Se/Se By total pressure measurements of compositions in the subsystem Bi₂Se₃/Bi₂O₂Se/Se was shown, that in thermodynamic equilibrium the three phases Bi₂Se₃/Bi₂O₂Se/Se coexist. The barogram of the triangle reduces to the barogram of the line Bi₂Se₃? Se, the compound Bi₂O₂Se is not from influence of the total pressure in the investigated temperature range.     

Synthesis of inosinate trimer I2′p5′I2′pt′I and tetramer I2′p5′I2′p5′I2′p5′I

The trimeric and tetrameric inosinates with (2′–5′)-linkages were synthesized via the phosphotriester approach using the p-nitrophenylethyl group for phosphate protection.     

FTIR study of the DMS/NO2/I2/N2 photolysis system: The reaction of IO radicals with DMS

A steady-state system involving the photolysis of NO₂ in an excess of I₂ as a source of IO radicals has been used to study the reaction IO + DMS in 760 Torr N₂ at 296 K. IO radicals were found to react rapidly with DMS, one molecule of DMSO being produced for each molecule of DMS consumed. Numerical analysis of the experimental results yielded a rate constant of (3.0 ± 1.5) × 10^?11 cm³ s^?1 for the reaction IO + DMS → DMSO + I.     

Vibrational spectrum of I(H2O)

The infrared spectrum of the ionic cluster I⁻(H₂O) was recorded from 3170 to 3800 cm⁻¹ by vibrational predissociation spectroscopy. A strong multiplet observed at 3415 cm⁻¹ and a narrow band at 3710 cm⁻¹ were assigned as a hydrogen-bonded OH stretch and free OH stretch respectively, indicating that H₂O forms a single hydrogen bond with the iodide anion. Ab initio vibrational frequencies and intensities were computed at the second-order Møller-Plesset (MP2) level for the minimum energy configuration, a nearly linear hydrogen-bonded isomer, and for a low-lying saddlepoint, a symmetric C_2v bridged isomer. The spectrum predicted for the hydrogen-bonded isomer agreed well with experiment.     

微波辐射I2／Al2O3催化合成腈类化合物

微波辐射下,I2/Al2O3催化芳香醛和盐酸羟氨的无溶剂反应.一锅法合成了腈类化合物,产率80%～99%.     

Efficient Simmons–Smith cyclopropanation with Zn/Cu and CH2I2

An appropriate solvent to perform the original Simmons–Smith reaction was reinvestigated. Among available solvents, cyclopentyl methyl ether (CPME), a recently commercialized ethereal solvent, was found to be the best so far. Compared with Et₂O under reflux – the commonest conditions – reaction completion in CPME at 50 °C was about 10 times faster. The product yields and selectivities were mostly identical to those with Et₂O, but were better in some cases; e.g. 13–56% with 2‐cyclohexenol. The good performance of CPME should be mainly due to its moderate polarity and high boiling point. Copyright © 2012 John Wiley & Sons, Ltd.     

I2O5/NaNO2硝化富电子芳香族化合物

以富电子芳香族化合物为底物,在五氧化二碘和亚硝酸钠作用下,温和条件下直接硝化得到其相应的芳香族硝基化合物,所得硝化产物结构经¹H NMR,MS和熔点表征。并研究其可能的自由基反应历程。      

Zu den Phasenverhältnissen im System V/Nb/O. I. Koexistenzbeziehungen im Bereich V2O5/Nb2O5/VO2/NbO2

The Phase Relations in the System V/Nb/O. I. Coexistence Relations in the Section V₂O₅/Nb₂O₅/VO₂/NbO₂ . Phase relations in the section Nb₂O₅/V₂O₅/VO₂/NbO₂ of the ternary system V/Nb/O have been studied by X-ray diffraction. The investigated samples were prepared by high temperature synthesis at 900°C–1000°C. The section Nb₂O₅/V₂O₅/VO₂/NbO₂ is charakterized by fife three phase regions: The limits of solubility of the pseudobinary system were ascertained by determination of lattic parameters of powder samples:      

Diethylzinc/metal salt initiator systems. I. Stereospecific polymerization of N-vinylcarbazole by ZnEt2/CoCl2-quinoline

In the presence of ZnEt₂ the CoCl₂-quinoline complex polymerizes NVC with a rate increasing with ZnEt₂ and CoCl₂-Q concentrations up to a certain concentration of ZnEt₂ or CoCl₂-Q, thereafter becoming independent of either. At a fixed concentration of ZnEt₂ and CoCl₂-Q the rate is second order with respect to NVC. The poly(NVC) obtained is freely soluble in benzene but leaves some insoluble fraction in methyl ethyl ketone, which has been characterized by ¹³C-NMR to be a stereoblock polymer. X-ray diffraction, IR, and thermal characteristics of the polymer have also been reported. [η] is virtually independent of monomer, in the concentration range 0.1–0.25 mol/L ZnEt₂ and CoCl₂-Q concentrations. Oxygen as an additive inhibits the polymerization. A cationic coordination mechanism has been proposed and appropriate rate and degree of polymerization equations have been suggested.     

DMSO/N2H4.H2O/I2/H2O/CH3CN: a new system for selective oxidation of alcohols in hydrated media

A new alternative system for the oxidation of secondary alcohols to ketones with DMSO/N2H4.H2O/I2/H2O/CH3CN in hydrated media has been developed. The system also selectively oxidizes the secondary alcoholic groups to the corresponding ketones in the presence of primary alcoholic groups present within the same molecule in moderate to very good yields at reflux temperature.