Electrochemical Oxidation of Catechols in the Presence of Triethyl Phosphite

The mechanism of electrochemical oxidation of catechol and some of its derivatives have been studied in the presence of triethyl phosphite as a nucleophile in aqueous solution. Voltammetric studies indicate that the quinones derived from catechol, and its derivatives, participate in Michael addition reaction with triethyl phosphite. The reaction mechanism consists of electron transfer followed by a chemical reaction which is named as an EC mechanism. The homogeneous rate constants (k_obs) were estimated by comparing the experimental cyclic voltammograms with the digitally simulated voltammograms based on EC mechanism. Also the effects of nucleophile concentration and substituted group of catechols on voltammetric behavior and the rate constants of chemical reactions were examined.     

Synthesis and characterization of a new organically templated open-framework beryllium phosphite with 3, 4-connected networks

Employing diethylenetriamine (=dien) as a structure-directing agent, a new open-framework beryllium phosphite H₂dien·Be₃(HPO₃)₄ (1), has been synthesized hydrothermally and structurally characterized by single crystal X-ray diffraction. The structure of 1 features a (3, 4)-connected framework with 8- and 12-ring channels, which is constructed from strictly alternating BeO₄ tetrahedra and HPO₃²⁻ pseudopyramids. The 3-D framework possesses a pcu topology when the heptameric [Be₃(HPO₃)₄] clusters are regarded as 6-connected secondary building units. Crystal data: 1, monoclinic, C2/c (no. 15), a = 8.7350(3) Å, b = 15.1704(6) Å, c = 13.0851(4) Å, β = 101.223(5)°, V = 1700.79(10) Å³, Z = 4, R₁ = 0.0625, wR₂ = 0.1692.     

Development of a Ruthenium/Phosphite Catalyst System for Domino Hydroformylation–Reduction of Olefins with Carbon Dioxide

An efficient domino ruthenium‐catalyzed reverse water‐gas‐shift (RWGS)‐hydroformylation‐reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence.     

The inorganic–organic hybrid zinc phosphite poly[(μ3‐hydrogen phosphito‐κ3O:O′:O′′)(piperidin‐1‐ium‐4‐carboxylate‐κO)zinc(II)]

A new inorganic–organic hybrid zinc phosphite, [Zn(HPO₃)(C₆H₁₁NO₂)]_n, has been synthesized hydrothermally. Protonated piperidin‐1‐ium‐4‐carboxylate (PDCA) was generated in situ by hydrolysis of the piperidine‐4‐carboxamide precursor. The P atom possesses a typical PO₃H pseudo‐pyramidal geometry. The crystal structure features an unusual (3,4)‐connected two‐dimensional inorganic zinc–phosphite layer, with organic PDCA ligands appended to the sheets and protruding into the interlayer region. Helical chains of opposite chirality are involved in the construction of a puckered sheet structure.     

Aging properties of radiation vulcanized NR latex film

A simple method was developed to evaluate the antioxidant activity for radiation vulcanized natural rubber latex. Tris(nonylated phenyl) phosphite has been selected as the effective antioxidant. This antioxidant is prone to hydrolyze under high humidity condition, resulting in the easy decomposition of radiation vulcanizate in the environment.     

Trichloroisocyanuric acid: an efficient reagent for the synthesis of dialkyl chlorophosphates from dialkyl phosphites

A mild and operationally simple method for the synthesis of dialkyl chlorophosphates is described. Trichloroisocyanuric acid is used as an effective reagent for the rapid conversion of dialkyl phosphites to their corresponding dialkyl chlorophosphates under mild conditions.     

Assembly of two novel inorganic–organic hybrid solids based on 3-(aminomethyl)pyridine ligand

Two new inorganic–organic hybrids, (Hampy)Zn₂(PO₄) (HPO₃) (1) and (ampy)Zn₂(HPO₃)₂ (2), where ampy = 3-(aminomethyl)pyridine, have been solvothermally prepared and structurally characterized. Compound 1 exhibits an unusual two-dimensional layer structure, which possesses a central 4.8² zincophosphate sheet wrapped by infinite zincophosphite chains. Left- and right-handed helical chains participate in the formation of the zincophosphate layer. Compound 2 features a three-dimensional pillared-layer structure, in which two-dimensional Zn^II(HPO₃) inorganic sheets were cross-linked by ampy ligands. The simultaneous occurrence of zinc-amine helical chains in 2 is unique and, to the best of our knowledge, firstly encountered in phosphite/phosphate hybrid materials. Different coordination modes and roles of the same ampy ligand were observed in the formation of the hybrid structures.     

Deoxygenation of 5-O-benzoyl-1,2-isopropylidene-3-O-imidazolylthiocarbonyl-α-d-xylofuranose using dimethyl phosphite: an efficient alternate method towards a 3′-deoxynucleoside glycosyl donor

An efficient radical deoxygenation reaction of thiocarbonylimidazolyl activated glycoside analogue using dimethyl phosphite as hydrogen source and radical chain carrier was performed as a key step in a multi step synthesis towards a common 3-deoxy glycosyl donor for 3′-deoxynucleosides. This method has safety and cost advantages compared to the generally used radical reduction reagents.     

Addition of dimethyl phosphite to N,N'-dialkyl- and -diaryl terephthalaldimines and its stereochemistry contrary to behavior of other analogues

The addition of dimethyl phosphite to N,N'-terephthalylidene-alkyl- (or aryl-) amines resulted in new tetramethyl 1,4-phenylene-bis-(N-alkylaminomethyl)-phosphonates in moderate yields. The stereochemical behavior of these reactions was studied by NMR, demonstrating that the reactions lead to the formation of both possible diastereomeric forms from 1:1 to 1:2 ratios. This was unexpected considering that previously investigated additions of diethyl, dibenzyl, and diphenyl phosphites to terephthalaldimines were diastereoselective up to 100%. Attempts were made to find reasonable explanation for the phenomenon using semi-empirical and DFT calculations.     

Ga_8(H_2O)_6(HPO_3)_(14)·(C_3N_2H_6)_3·H_3O:含有经典6* 1 SBU的新型三维开放骨架亚磷酸镓

为了丰富亚磷酸盐结构,为多孔材料的定向合成提供一定的实验数据,在溶剂热的条件下,以咪唑为结构导向剂合成了一个具有三维开放骨架结构的新型亚磷酸镓化合物Ga8(H2O)6(HPO3)14·(C3N2H6)3·H3O(化合物1),并通过粉末X-射线衍射、红外光谱、热重、ICP和CHN元素分析对化合物进行了表征。单晶X-射线衍射分析结果表明,化合物1属于三斜晶系,P-3c1空间群,晶胞参数为a=b=1.33388(8)nm,c=1.7886(2)nm,γ=120(4)°,Z=2。其结构是由Ga O6八面体和[HPO32-]假四面体单元相互连接构成。该结构沿着[100]和[010]方向具有12元环孔道。值得注意的是,在化合物1的结构中存在两种不同的次级结构单元(SBU):经典的6*1单元Ga3P4和齿轮状的Ga P6单元。