A Systems Approach to a One-Pot Electrochemical Wittig Olefination Avoiding the Use of Chemical Reductant or Sacrificial Electrode

An unprecedented one-pot fully electrochemically driven Wittig olefination reaction system without employing a chemical reductant or sacrificial electrode material to regenerate triphenylphosphine (TPP) from triphenylphosphine oxide (TPPO) and base-free in situ formation of Wittig ylides, is reported. Starting from TPPO, the initial step of the phosphoryl P=O bond activation proceeds through alkylation with RX (R=Me, Et; X=OSO₂CF₃ (OTf)), affording the corresponding [Ph₃POR]⁺X⁻ salts which undergo efficient electroreduction to TPP in the presence of a substoichiometric amount of the Sc(OTf)₃ Lewis acid on a Ag-electrode. Subsequent alkylation of TPP affords Ph₃PR⁺ which enables a facile and efficient electrochemical in situ formation of the corresponding Wittig ylide under base-free condition and their direct use for the olefination of various carbonyl compounds. The mechanism and, in particular, the intriguing role of Sc³⁺ as mediator in the TPPO electroreduction been uncovered by density functional theory calculations.     

Biohydrogen Production from Mushroom Cultivation Waste by Anaerobic Solid‐state Fermentation

Mushroom cultivation waste (MCW) is a polypropylene bag stuffed with wood flour and nutrients for growing mushroom, which is a feasible feedstock for anaerobic biohydrogen production owing to its abundant availability, high organic and nutrient content. This study optimized the seed inoculum from various waste sludges (sewage sludge, cow dung and pig slurry), nutrient addition and operation conditions (moisture content and MCW powder particle size) for maximal biohydrogen production by solid‐state fermentation (SSF). SSF batch test was operated at a MCW 3 g total volatile solid (TVS)/L, temperature 55 °C and rotation speed of 15 rpm with a vertical rotative shaker. The peak hydrogen production performance of hydrogen production rate (HPR) 9.50 mol H₂/kg‐d and hydrogen yield (HY) 0.29 mmol H₂/g TVS) are obtained using sewage sludge 2 seed inoculum, nutrients addition, moisture content 70 % and particle size of 1.190～0.590 mm. The results show that the MCW has the potential for hydrogen production by anaerobic mixed microflora using solid‐state fermentation. The bioenergy of 1842 kWh while using SSF to conver MCW to produce biohydrogen and it could reduce CO₂ emission of 114–178 kg per year comparing using fossil fuel such as coal, fuel oil and natural gas.     

Mimicking the Aromatic‐Ring‐Cleavage Activity of Gentisate‐1,2‐Dioxygenase by a Nonheme Iron Complex

Gentisate‐1,2‐dioxygenase (GDO), a nonheme iron enzyme in the cupin superfamily, catalyzes the cleavage of the aromatic‐ring of 2,5‐dihydroxybenzoic acid (gentisic acid) to form maleylpyruvic acid in the microbial aerobic degradation of aromatic compounds. To develop a functional model of GDO, we have isolated a nonheme iron(II) complex, [(Tp^Ph2)Fe^II(DHN‐H)] (Tp^Ph2=hydrotris(3,5‐diphenylpyrazole‐1‐yl)borate, DHN‐H=1,4‐dihydroxy‐2‐naphthoate). In the reaction with O₂, the biomimetic complex oxidatively cleaves the aromatic ring of the coordinated substrate with the incorporation of both the oxygen atoms from molecular oxygen into the cleavage product. The presence of para‐hydroxy group on the substrate plays a crucial role in directing the aromatic‐ring cleaving reaction.     

Condensed two- and three-dimensional aromatic systems: a theoretical study on the relative stabilities of isomers of CB19H16+, B20H15Cl, and B20H14Cl2 and comparison to B12H10Cl22-, C6H4Cl2, C10H7Cl, and C10H6Cl2

DFT studies (B3LYP/6-31G) on mono- and dichloro derivatives of benzene, naphthalene, B12H12(2-), four-atom-sharing condensed systems B20H16, and monocarborane isomers of B20H16 are used to compare the variation of relative stability and aromaticity between condensed aromatics. The trends in the variation of the relative energies and aromaticity in these two- and three-dimensional systems are similar. Aromaticity, estimated by NICS values, does not change considerably with condensation or substitution. The minor variation in the relative energies of the isomers of chloro derivatives is explained by the topological charge stabilization rule of Gimarc. The compatibility of the cap and ring orbitals decides the relative stability of CB19H16+.     

Ferromagnetic coupling in trinuclear, partial cubane Cu(II) complexes with a micro(3)-OH core: magnetostructural correlations

Three new trinuclear copper(II) complexes, [(CuL(1))(3)(micro(3)-OH)][ClO(4)](2).3 H(2)O (1), [(CuL(2))(3)(micro(3)-OH)][ClO(4)](2).H(2)O (2), and [(CuL(3))(3)(micro(3)-OH)][ClO(4)](2).7 H(2)O (3) have been synthesized from the three tridentate Schiff bases HL(1), HL(2), and HL(3) (HL(1)=6- aminomethyl-3-methyl-1-phenyl-4-azahex-2-en-1-one, HL(2)=6-aminoethyl-3-methyl-1-phenyl-4-azahex-2-en-1-one, and HL(3)=6-aminodimethyl-3-methyl-1-phenyl-4-azahex-2-en-1-one). They have been characterized by X-ray crystallography and IR and UV spectroscopy, and their magnetic properties have been investigated. All the compounds contain a partial cubane [Cu(3)O(4)] core consisting of the trinuclear unit [(CuL)(3)(micro(3)-OH)](2+), perchlorate ions, and water molecules. In each of the complexes, the copper atoms are five-coordinate with a distorted square-pyramidal geometry except complex 1, in which one of the Cu(II) of the trinuclear unit is weakly coordinated to one of the perchlorate ions. Magnetic measurements performed in SQUID MPMS-XL7 using polycrystalline samples at an applied field of 2 kOe indicate a global intramolecular ferromagnetic coupling. Magnetostructural correlations have been calculated on the basis of theoretical models without symmetry restriction. Continuous shape measurements are an appropriate tool for establishing the degree of distortion of the Cu(II) from square-planar geometry. Structural, theoretical, and experimental magnetic data indicate that the higher the degree of distortion, the greater the ferromagnetic coupling.