Phosphorylation of Acylated Trihydroxybenzene Derivatives by Phosphorous Triamides

Abstract

The phosphorylation of acylated trihydroxybenzene derivatives by amides of phosphorous acid was considered. The possibility of selective phosphorylation of triacetoxy phloroglucin was shown.

GRAPHICAL ABSTRACT      

Investigation and Application of Polarographic Catalytic Wave of Oxygen Reduction Caused by Mefenamic Acid

The polarographic catalytic wave of oxygen reduction caused by mefenamic acid (MA) with redox properties was reported in this paper. The electrochemical process of the catalytic wave was proposed that the superoxide anion O(?) was generated polarographically and the dismutation of the O(?) was catalyzed by MA to reproduce O_2 and H_2O_2. This explained chemically the scavenging of the O_2~- by MA im biomedical area. Based on the catalytic wave, a new method for the determination of MA by single-sweep polarography was developed.     

Synthesis,structure and catalase activity of the [TPA2Mn2(μ-Cl)2] complex

The dinuclear Mn complex (Et₃NH)₂[TPA₂Mn₂(μ-Cl)₂](ClO₄)₄ (I) was synthesized and characterized. Complex I was obtained from the reaction between MnCl₂ and [H₃TPA](ClO₄)₃ in MeOH. Structural analysis of I showed the two Mn(II) atoms are bridged by two chloride ligands, forming a bis(μ-chloro)dimanganese core. The [Mn₂(μ-Cl)₂]²⁺ core, with a Mn–Mn distance of 3.521(2) Å, is similar to the active site found in chloride-inhibited Mn catalase. EPR and temperature-dependent magnetic susceptibility measurements of complex I showed an antiferromagnetic interaction between the two S = 5/2 Mn centers with an exchange parameter J = −8.8 cm⁻¹. Catalytic activity of H₂O₂ dismutation was measured for complex I and compared with other related complexes. Kinetic parameters of H₂O₂ dismutation were obtained and a possible catalytic mechanism of complex I, related to chloride-inhibited Mn catalase, was suggested.     

Schiff碱稀土配合物的合成及其对超氧离子的催化歧化作用

A Schiff base ligand was synthesized by condensating 5- bromosalicylaldehyd with ethylenediamine and several rare earth complexes,such as La(Ⅲ)、Ce(Ⅲ)、Nd(Ⅲ) were synthesized.The compositions and structures of the ligang and its complexes were characterized by the elemental analyses,thermal analyses,IR spectra,UV spectra,1~H NMR and molar conductivity.The fluorescence property and dismutation to O_2~- free radical were also investingated.     

Dismutation of Diamidoarylphosphites

Some examples of spontaneous dismutation of diamidoarylphosphites in different solvents were studied, and features of the process were revealed.     

The Remarkable Effect of the Manganese Ion with Dioxygen on the Stability of π‐Conjugated Radical Cations

In this paper, nanosecond laser flash photolysis has been used to investigate the influence of metal ions on the kinetics of radical cations of a range of carotenoids (astaxanthin (ASTA), canthaxanthin (CAN), and β‐carotene (β‐CAR)) and various electron donors (1,4‐diphenyl‐1,3‐butadiene (14DPB), 1,6‐diphenyl‐1,3,5‐hexatriene (16DPH), 4‐methoxy‐trans‐stilbene (4 MeOSt), and trans‐stilbene (trans‐St)) in benzonitrile. Radical cations have been generated by means of photosensitized electron‐transfer (ET) using 1,4‐dicyanonaphthalene (14DCN) and biphenyl (BP). The kinetic decay of CAR ^{. +} shows a strong dependence on the identity of the examined metal ion. For example, whereas NaClO₄ has a weak effect on the kinetics of CAR ^{. +}, Ni(ClO₄)₂ causes a strong retardation of the decay of CAR ^{. +}. It is also interesting to note that Mn²⁺, which is a biologically relevant metal ion, shows the strongest effect of all the investigated metal ions (e.g., in the presence of Mn²⁺ ions, the half‐life (t_1/2) of CAN ^{. +} (t_1/2>90 ms) is more than three orders of magnitude higher than in the absence of the metal ions (t_1/2≈16 μs)). Furthermore, the influence of metal‐ion and oxygen concentrations on the kinetics of CAR ^{. +} reveals their pronounced effect on the kinetic decay of CAR ^{. +}. However, these remarkable effects are greatly diminished if either oxygen or metal ions are removed from the investigated solutions. Therefore, it can be concluded that oxygen and metal ions interact cooperatively to induce the observed substantial effects on the stabilities of CAR ^{. +}. These results are the first direct observation of the major role of oxygen in the stabilization of radical cations, and they support the earlier mechanism proposed by Astruc et al. for the role of oxygen in the inhibition of cage reactions. On the basis of these results, the factors that affect the stability of radical cations are discussed and the mechanism that shows the role of oxygen and metal ions in the enhancement of radical‐cation stability is described.     

Preparation and Characterization of Cu(II) Phthalocyanine Tetrasulfonate Intercalated and Supported on Layered Double Hydroxides

The aim of the present work was to synthesize and characterize layered doublehydroxides (LDHs), in the magnesium/aluminum form, intercalated with copper(II)phthalocyanine tetrasulfonate (CuPcTs). The metal complex was immobilized intothe LDH gallery region through the reconstitution method and this material wascharacterized by X-ray diffraction (XRD), surface area and porosity measurements,elementary analysis, thermogravimetry (TGA), vibrational (IR) and electronic(UV-visible) spectroscopies, and electronic paramagnetic resonance (EPR). Thecatalytic performance of CuPcTs intercalated and supported on the LDH wasevaluated by carrying out the hydrogen peroxide dismutation. The CuPcTs wassuccessfully intercalated into the LDH layers according to XRD data (the basalspacing of the carbonate precursors increases by approximately 15Å inthe intercalated samples). The surface area and porosity analysis suggested thatthe CuPcTs intercalated materials are not microporous solids. Samples containingthe metal complex confined between the LDH layers have an appreciable thermalstability: decomposition is not observed at least up to 400 °C. TGA experiments also show that the weight-loss curves of the CuPcTs supported samples superimpose those recorded for the CuPcTs complex and the LDH-carbonate while the curves for theintercalated materials are unique. CuPcTs intercalated or supported on LDHs is notactive in the hydrogen peroxide dismutation although the free form shows activity at pH above 8.     

Dismutation of Bisphosphorylated Aromatic Diols

Abstract

The first study of the dismutation of aromatic diol bisdiamidophosphites has been performed. Derivatives of condensed aromatic systems dismutate more rapidly than their mononuclear analogues. Amide derivatives with aliphatic substituents at the nitrogen atom undergo dismutation more readily than their heterocyclic analogues. In methylene chloride, the process proceeded most rapidly regardless of the aromatic component and the substituent at the phosphorus atom. Apolar solvents (benzene and diethyl ether) did not favor the dismutation. Temperature had no effect on the time of dismutation, and a catalyst decreased it by a factor of 1.5–2.     

高比表面积α-AlF3的制备和表征

采用炭硬模板法制备了高比表面积的α-AlF3(HS-α-AlF3)。首先,将一定浓度的蔗糖溶液浸渍到γ-Al2O3中,然后经过热处理,使得蔗糖分解为炭。其次,将含炭的γ-Al2O3固体用HF气体进行氟化。最后,再利用燃烧法除去炭硬模板。采用XRD、低温氮吸附-脱附、NH3-TPD、SEM-EDX等技术对样品进行了表征。结果表明,当炭化温度为450℃时,HF-N2混合气体积比为1:4,除碳温度为425℃时,制得的α-AlF3比表面积最大,为66 m2.g-1。此外,HS-α-AlF3催化剂对CCl2F2歧化反应的催化活性也明显高于常规方法制备的低比表面积的α-AlF3,这是因为高比表面积的α-AlF3催化剂具有较大的酸量。