AlCl(3) x 6H(2)O/KI/H(2)O/CH(3)CN: a new alternate system for dehydration of oximes and amides in hydrated media

Dehydration of oximes and amides to nitriles was carried out using the AlCl(3) x 6H(2)O/KI/H(2)O/CH(3)CN system. It produced isoquinoline derivatives 8a-c (Bischler Naperialski reaction) when reacted with amides 7a-c in hydrated media. Also, the keto oximes produced anilides (Beckmann rearrangement) with the system under the same reaction conditions.     

OH−-induced β-elimination reactions with 1-(2-Xethyl)-4-nitrobenzene substrates in solvent mixture H2O/CH3CN and H2O/DMSO: Reactivity and mechanism

The behaviour of 1-(2-bromoethyl) 4-nitrobenzene (1), N,N,N-triethyl-2-(4-nitrophenyl)ethanaminium bromide (2) and N,N-diethyl-N-[2-(4-nitrophenyl)ethyl]octan-1-aminium bromide (3) in the OH⁻-induced elimination reactions with formation of 1-nitro-4-vinylbenzene in mixtures of DMSO/H₂O or CH₃CN/H₂O has been investigated. With all three substrates an increase in dipolar aprotic solvent content implies a limited increase of the second-order rate constant k _OH up to ≅605, and then an exponential increase is observed. The variation of activation parameters ΔH ^# and dGS ^#, measured in DMSO/H₂O mixtures, is parallel for 1 and 2. This similar behaviour of 1 and 2 with respect to variation in solvent composition is evidence that it is not possible to use this technique of solvent effect for the mechanistic diagnosis of elimination reactions.     

Enthalpy of mixing of hydrated melts I: The system (ZnCl2.4H2O)−(LiCl.4H2O)

Measurements of the enthalpy of mixing at 25°C for the hydrate system (ZnCl₂+RH₂O)?(LiCl+RH₂O) are reported. A distinct maximum and a pronounced shoulder appears in the enthalpy of mixing data at mole fractions of X_ZnCl2=0.33 and 0.50, respectively, forR equal to about 4.     

Solvent- and metal-free selective oxidation of thiols to disulfides using I2/DMSO catalytic system

We describe herein a simple, fast and inexpensive protocol for the oxidative coupling of thiols employing a stoichiometric amount of DMSO and iodine as the catalyst. Various aromatic disulfides were obtained in good to excellent yields in short reaction times at room temperature, while aliphatic disulfides were achieved in good yields when the reactions were conducted under microwave irradiation.     

mpg-C(3)N(4)-Catalyzed selective oxidation of alcohols using O(2) and visible light

Mesoporous carbon nitride (mpg-C(3)N(4)) polymer can function as a metal-free photocatalyst to activate O(2) for the selective oxidation of benzyl alcohols with visible light, avoiding the cost, toxicity, and purification problems associated with corresponding transition-metal systems. By combining the surface basicity and semiconductor functions of mpg-C(3)N(4), the photocatalytic system can realize a high catalytic selectivity to generate benzaldehyde. The metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes/ketones, demonstrating a potential pathway of accessing traditional mild radical chemistry with nitroxyl radicals.     

HPC/H2O/H3PO4 tertiary system: a rheological study

This study characterizes the rheological behavior of the HPC/H₂O/H₃PO₄ tertiary system based on the 3-D phase diagram that was obtained in our earlier work. The effects of frequency, temperature, HPC concentration, liquid composition (H₂O/H₃PO₄ ratio), and phase status on the rheological parameters were thoroughly investigated. The most useful parameter for distinguishing the isotropic (I) and liquid crystalline (LC) phases was tanδ. Agglomeration in the cloudy suspension (CS) phase at high temperature was too severe to allow a smooth flow, so the tanδ and η* represented significant damping, which is a good indicator of the presence of the CS phase. With an increase in temperature, the viscosity of the flow with a single homogeneous phase—either the I phase or the LC phase—or a combination of two homogeneous phases in sequence, obeyed the Arrhenius model. In contrast, once the temperature rose to that of the formation of heterogeneous CS phase, the Arrhenius model was no longer valid. The activation energy E of the I phase was greater, and more sensitive to the HPC concentration, than the LC phase. Finally, the concentration of the sol/gel transition (SGT) declined as temperature increased but increased as the H₃PO₄ content increased. Furthermore, this tertiary system exhibited no clear order of the onsets of the formations of SGT phase, the LC phase, and the CS phase as HPC concentration was varied.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

Solubility, complex formation, and redox reactions in the Tl2O3-HCN/CN(-)-H2O system. Crystal structures of the cyano compounds Tl(CN)3.H2O, Na[Tl(CN)4].3H2O, K[Tl(CN)4], and Tl(I)[Tl(III)(CN)4] and of Tl(I)2C2O4

Thallium(III) oxide can be dissolved in water in the presence of strongly complexing cyanide ions. Tl(III) is leached from its oxide both by aqueous solutions of hydrogen cyanide and by alkali-metal cyanides. The dominating cyano complex of thallium(III) obtained by dissolution of Tl2O3 in HCN is [Tl(CN)3(aq)] as shown by 205Tl NMR. The Tl(CN)3 species has been selectively extracted into diethyl ether from aqueous solution with the ratio CN-/Tl(III) = 3. When aqueous solutions of the MCN (M = Na+, K+) salts are used to dissolve thallium(III) oxide, the equilibrium in liquid phase is fully shifted to the [Tl(CN)4]- complex. The Tl(CN)3 and Tl(CN)4- species have for the first time been synthesized in the solid state as Tl(CN)3.H2O (1), M[Tl(CN)4] (M = Tl (2) and K (3)), and Na[Tl(CN)4].3H2O (4) salts, and their structures have been determined by single-crystal X-ray diffraction. In the crystal structure of 1, the thallium(III) ion has a trigonal bipyramidal coordination with three cyanide ions in the equatorial plane, while an oxygen atom of the water molecule and a nitrogen atom from a cyanide ligand, attached to a neighboring thallium complex, form a linear O-Tl-N fragment. In the three compounds of the tetracyano-thallium(III) complex, 2-4, the [Tl(CN)4]- unit has a distorted tetrahedral geometry. Along with the acidic leaching (enhanced by Tl(III)-CN- complex formation), an effective reductive dissolution of the thallium(III) oxide can also take place in the Tl2O3-HCN-H2O system yielding thallium(I), while hydrogen cyanide is oxidized to cyanogen. The latter is hydrolyzed in aqueous solution giving rise to a number of products including (CONH2)2, NCO-, and NH4+ detected by 14N NMR. The crystalline compounds, Tl(I)[Tl(III)(CN)4], Tl(I)2C2O4, and (CONH2)2, have been obtained as products of the redox reactions in the system.     

[Mo2FeS8O2][Et4N]3CH3CN原子簇化合物的晶体结构

[Mo_2FeS_8O_2][Et_4N]_3·CH_3CN晶体属三斜晶系,PI空间群.α=9.998(1)A,b=13.868(3)A,c=16.796(3)A,α=74.66(2)°,β=85.41(1)°,ν=72.21(1)°,Ζ=2.结构参数经块矩阵最小二乘法精修后,最后的偏离因子R=0.037,R_w=0.034.平均键长Mo—Fe为2.722A,Mo—S为2.358A,Fe—S为2.244A,Mo—O为1.697A.结果表明:标题化合物是一个结构新颖的原子簇化合物.它是由一个三价原子簇阴离子与三个一价的乙基季铵阳离子靠静电引力结合在一起,又溶剂合一个乙氰分子的原子簇化合物而形成.     

N(CH3)4]2[Mn(H2O)]3[Mo(CN)7](2).2H2O: a new high Tc cyano-bridged ferrimagnet based on the [MoIII(CN)7]4- building block and induced by counterion exchange

The title compound was synthesized by slow diffusion of aqueous solutions containing K4[Mo(CN)7].2H2O, [Mn(H2O)6](NO3)2, and [N(CH3)4]Cl. The compound crystallized in monoclinic space group C2/c, a = 25.8546(14), b = 12.3906(7), c = 13.5382(7) A, beta = 116.4170 (10) degrees, Z = 4, R = 0.0353, wR2 = 0.0456. The MoIII site is surrounded by six -C-N-Mn linkages and one terminal cyano group in a distorted capped-prism fashion. There are two pentahedral MnII sites in the structure, both with four -N-C-Mo linkages and one water molecule. The anisotropic three-dimensional structure consists of connected corrugated gridlike sheet layers parallel to the bc plane. Tetramethylammonium counterions ([N(CH3)4]+) located between these layers seem to induce their distortion. The three-dimensional organization may also be viewed as interconnected octagonal channels propagated along the c axis. The void space of these channels is occupied by coordinated and crystalized water molecules. Temperature and field dependence of the magnetization in both the dc and ac modes have been measured on polycrystalline sample. These investigations have revealed that the compound ordered ferrimagnetically at Tc = 86 K, with a small hysteresis effect. These findings have been compared to those reported previously for three- and two-dimensional materials of the same family.     

Syntheses, Spectroscopic Properties and Crystal Structures of （2-Cl-C6H4CH2）3SnS2CN（C5H10） and （2-Cl-C6H4CH2）3SnS2CN（C4H9N）

1 INTRODUCTION The chemistry of organotin(IV) complexes was extensively studied due to their biological activity and coordination chemistry[1～7]. More recently, phar- maceutical properties of alkyltin(IV) complexes with dithiocarbamate ligands have bee…     

IBX/n-Bu4NBr/CH2Cl2-H2O: a new mild system for selective oxidation of secondary alcohols

A new alternative system for the chemoselective oxidation of secondary hydroxyl group to ketone with IBX/n-Bu₄NBr in CH₂Cl₂-H₂O has been developed. Under the reaction conditions, the secondary hydroxyl group was highly chemoselectively oxidized to the corresponding ketone, in moderate to good yields at rt, in the presence of primary hydroxyl group within the same molecule.     

新型杂多化合物[(CH3CH2)4N]4H3O· {Na[(HMo2O5)3(HPO4)(H2PO4)3]2}·(H2PO4)2·10H2O的水热合成与晶体结构

杂多化合物在催化、医药、材料及光化学等方面具有广泛的应用前景 [1～ 4 ] ,其中钼磷多金属氧酸盐具有优异的氧化催化性能 [5,6 ] .近年来合成的新奇结构的钼磷多金属氧酸盐中已测定结构的有含帽[7,8] 和非帽[9～ 12 ] 系列 .本文利用水热法合成了未见文献报道的结构新颖的夹心型磷钼多金属氧酸盐[( CH3CH2 ) 4N]4 H3O{Na[( HMo2 O5) 3( HPO4 ) ( H2 PO4 ) 3]2 }· ( H2 PO4 ) 2 · 1 0 H2 O,并测定了其晶体结构 .1　实验与晶体结构分析1 .1　仪器与试剂　元素 Na用美国原子吸收分光光度计测定 ;C,H和 N用 Perkin- Elmer 2 4 0…     

Removal of NO in NO/N2, NO/N2/O2, NO/CH4/N2, and NO/CH4/O2/N2 systems by flowing microwave discharges

In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures.