Facile Routes to Manganese(II) Triflate Complexes

Manganese(II) chloride reacts with trimethylsilyl triflate (TMS(OTf) where OTf = (-)OSO(2)CF(3)) in a 1:1 mixture of acetonitrile and tetrahydrofuran, and after recrystallization affords the linear coordination polymer [Mn(II)(CH(3)CN)(2)(OTf)(2)](n). Each distorted octahedral manganese(II) center in the polymeric chain has trans-acetonitriles and the remaining equatorial coordination positions are occupied by the bridging triflate anions. Dissolving [Mn(II)(CH(3)CN)(2)(OTf)(2)](n) in equal volumes of acetonitrile and pyridine followed by recrystallization with diethyl ether yields trans-[Mn(II)(C(5)H(5)N)(4)(OTf)(2)]. The distorted octahedral geometry of the manganese center features monodentate trans-triflate anions and four equatorial pyridines. Exposure of either [Mn(II)(CH(3)CN)(2)(OTf)(2)](n) or [Mn(II)(C(5)H(5)N)(4)(OTf)(2)] to water readily gives [Mn(II)(H(2)O)(6)](OTf)(2). XRD reveals hydrogen-bonding interactions between the [Mn(II)(H(2)O)(6)](2+) cation and the triflate anion. All three of these species are easily crystallized and provide convenient sources of manganese(II) for further synthetic elaboration.     

Characterisation of manganese dioxides II. Kinetics of Interaction with Manganese (II) Ions in Aqueous Solution

The interaction between MnO₂ (I.C.S. No. 5), in the Na⁺ form and ⁵⁴Mn²⁺-labelled solution at pH 6 involves: a rapid process assumed to be Na⁺/Mn²⁺ ion-exchange and a slower process assumed to involve the exchange between Mn²⁺ ions in solution and Mn ions in a surface phase. The activation parameters ΔH^# and ΔS^# were found to be 52 and 83 kJ mol^?1 and ?130 and ?63 J mol^?1 for the two processes respectively. Exposing the solid to a flux of moderated neutrons had no effect on the rate of the second process. The exchange of Mn ions from the solid to the solution was demonstrated using ⁵⁶Mn-labelled solid and inactive Mn²⁺ solution. There was evidence of a still slower process.     

Antimicrobial, Antifertility and Antiinflammatory Approach to Tetradentate Macrocyclic Complexes of Iron(II) and Manganese(II)

Some antifertility inhibitors of 18 to 24-membered tetraazamacrocyclic complexes of iron(II) and manganese(II) have been synthesised by the template condensation using 1,3-phenylenediamine with malonic acid, succinic acid, glutaric acid and adipic acid. The reaction proceed smoothly to completion. The complexes were characterized by elemental analyses, molecular weight determinations, infrared, electronic, magnetic moment, mössbaur and mass spectral studies. The elemental analyses are consistent with the formation of the complexes [M(N₄L_n)Cl₂] (M = Fe(lI) or Mn(II)). All these complexes are stable and monomeric in nature as indicated by the molecular weight determinations. The spectral studies confirm the octahedral geometry around the central metal atom. The complexes have been screened in vitro against a number of fungi and bacteria to assess their growth inhibiting potential. The testicular sperm density and testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trials and biochemical parameters of reproductive organs have been examined and discussed.     

Manganese (II) Modified Heteropoly Compounds Studied by ESR

Tungstophosphoric lacunary heteropoly compounds modified with manganese ions ([PW₁₁Mn _x ]^5-, x = 1 - 0.02) were studied by means of ESR spectroscopy in the range of X-band. Presence of two manganese (II) species of different symmetry, characterized by two signals, one with g = ～2 and the second with g = 4.3, were found.     

Manganese(II)-Induced Oxidation of Limonene by Dioxygen

Manganese(II) complexes {[Mn^II(bpy)₂ ²⁺]_MeCN} in acetonitrile activate dioxygen for the oxidation of limonene to produce mainly carvone, carveol, limonene oxide, and perillaldehyde. The reaction efficiencies after 24 h reaction time are approximately 5-times higher than those obtained for analogous iron(II) complexes. However, the 5 h long induction period is observed for the common conditions of the reaction. The simultaneous presence of the catalyst, dioxygen and the substrate is necessary for the active species to be formed. When t-BuOOH is present in the reaction mixture, the induction period does not appear. In contrast, the replacement of t-BuOOH by HOOH completely inhibits the reaction. We have proposed a putative mechanism in which a manganese(IV)–hydroperoxo adduct with incorporated substrate is formed during the induction period and it becomes an active catalyst for limonene oxidation.     

Nematicidal, Fungicidal and Bactericidal Activities of Manganese (II) Complexes with Heterocyclic Sulphonamide Imines

Some manganese(II) complexes derived from different sulphadrugs and heterocyclic ketones have been prepared. These complexes have been characterized on the basis of elemental analyses, molecular weight determinations, conductivity measurements, infrared, ESR and magnetic measurements. The spectral data suggest that the ligands act in a monobasic, bidentate manner coordinating through nitrogen atom. A high spin tetrahedral geometry around this metal has been proposed on the basis of magnetic and spectral studies. The isolated products are coloured solids, soluble in DMSO, DMF and MeOH. All the complexes are monomeric in nature as indicated by their molecular weight determinations and conductivity measurements in dry DMF show them to be non-electrolytes. All the ligands and their corresponding complexes have been screened for their fungicidal, bactericidal and nematicidal activities.     

Polymer adsorption on multicomponent surfaces with relevance to membrane fouling

Block copolymer thin films that include low surface energy domains are analyzed as a possible way to overcome the problem of membrane fouling by proteins and other natural organic matter. A model is presented that accounts for both fouling due to chemical interactions between the solute and surface and due to convective deposition. Guidelines for the formation of novel membranes with improved fouling-resistant properties are suggested based on comparison of the relative permeate flux decline due to fouling on different model copolymer membranes. In general, it is observed that copolymer films having small and dispersed polymer blocks that interact unfavorably with the fouling species show an overall decrease in fouling and increase in permeate flux compared with the homopolymer films.     

Non-equilibrium glassy properties and their relevance in Case II transport kinetics

Some relevant non-equilibrium properties, frozen into the glassy matrix, have been considered, and related expressions for the excess chemical potential have been proposed. Both isotropic and anisotropic cases have been analysed. In the isotropic case, the out-of-equilibrium has been related to the excess volume over the value of the equilibrium liquid; the calculation of the energy related with the excess volume has been performed by using a liquid lattice constitutive equation. In the anisotropic case, use has been made of the entropy decrease due to the existing orientations. It is shown that, in both cases, the driving force for swelling is heavily influenced by the out-of-equilibrium which is frozen in the glass under the usual operating conditions; in particular, the out-of-equilibrium term becomes the dominant term in the anisotropic case at high orientations. In the isotropic case, the introduction of the excess over-equilibrium results in an improvement of a recently proposed kinetic model.     

微波消解-硫酸亚铁铵容量法测定锰矿石中锰的含量

锰矿石试样加磷酸于消化罐中微波消解,溶样完全,不生成焦磷酸盐。加氧化剂后用微波加热氧化,用硫酸亚铁铵标准溶液滴定测定锰的含量。本方法溶样能力强,操作简便,条件易控制,结果准确。     

硫氰酸锰及其相关衍生物的合成及化学表征

合成了金属有机配合物非线性光学晶体硫氰酸汞锰，及其相关衍生物，二二甲亚砜合硫氰酸汞锰，乙二醇一甲醚合硫氰酸汞锰，二水合二N，N－二甲基乙酰胺合硫氰酸汞锰，二水合二N－甲基－α－吡咯烷酮合硫氰酸汞锰。采用元素分析，红外光谱以及紫外－可见－近红外透央求我谱分析对其进行了化学表征。     

Change of mechanism of the hydrogen-electrode reaction with overpotential—II. hydrogen pressure equivalent to hydrogen overpotential and its relevance to the hydrogen embrittlement of metals

Electrochemical aspects of the hydrogen embrittlement are discussed in terms of a possible mechanism change of the hydrogen-electrode reaction occurring at the surface of the metal. Hydrogen pressure equivalent to hydrogen overpotential is formulated for the discharge-combination and the discharge-ion + atom-desorption routes in general forms, including the cases with comparable magnitudes of exchange cds of the constituent steps. The hydrogen pressure data observed by DeLuccia et al on iron in acidic solution are analysed. It is demonstrated that the data are well explained on the basis of the model that the hydrogen-electrode reaction on iron proceeds through the discharge-combination route with the exchange cd of the discharge step about one order of magnitude lower than that of the combination step.     

Direct Oxidation of Toluene to Benzoic Acid with Molecular Oxygen over Manganese Oxides

Manganese oxides, which are easily prepared, simple to use and capable of being recycled, have been employed as catalyst in the selective oxidation of toluene to benzoic acid for the first time. Molecular oxygen was used as oxidant under additive- and solvent-free conditions. As a result, 39% conversion of toluene and 93% selectivity of benzoic acid were achieved.     

Stabilization of Cubic Zirconia with Manganese Oxide

A directionally solidified eutectic (DSE) of MnO-ZrO₂ has been investigated using a variety of electron optical techniques. It is found that considerable MnO goes into ZrO₂ to form a substitutional solid solution. About 14 wt% of MnO is soluble in ZrO₂ close to the eutectic temperature. The solubility of ZrO₂ in MnO, however, is quite low, less than 0.50 wt%. Electron diffraction experiments indicate that ZrO₂ (MnO) has the cubic fluorite structure. Diffuse scattering, similar to other cubic zirconias (e.g., CaO, MgO stabilized zirconia), is also observed in manganese-stabilized zirconia. Diffuse scattering indicates the presence of oxygen vacancies and thus confirms the defect nature of the fluorite structure. Electron energy loss spectrometry (EELS) fine structure analysis of the Mn L₂₃ edge provided clear evidence that Mn is present as Mn²⁺ in Mn-stabilized cubic ZrO₂.     

Manganese(II)-promoted ligand oxidation during the formation of a coordination polymer

During the synthesis of Mn(II) compounds from fluorene-2,7-dicarboxylate, the ligand undergoes in situ oxidation to generate a Mn(II) coordination polymer with the ligand fluorenone-2,7-dicarboxylate (FODC^2 −). It was demonstrated that the transformation occurs with dioxygen as reactant and Mn(II) as catalyst. The resulting coordination polymer, [Mn₃(FODC)₃(DMA)₄]⋅2.5DMA, displays a 2D network based on the [Mn₃(COO)₆(DMA)₄] unit with triple carboxylate bridges. Magnetic analyses were performed not only on temperature-variable susceptibility but also on field-variable magnetization, indicating weak antiferromagnetic interactions through the triple bridges.