Ming-Yang He

Cobalt ferrite–polyaniline heteroarchitecture: a magnetically recyclable photocatalyst with highly enhanced performances

A cobalt ferrite–polyaniline photocatalyst is successfully prepared by in situ oxidative polymerization. The excellent magnetic properties of CoFe2O4 are maintained in the composite to some extent, and therefore the photocatalyst can be separated easily by an external magnetic field. A significant adsorption can be observed in the case of the anionic dyes and neutral dyes because the negatively charged groups or the electron-rich groups of these dyes undergo chemical interactions with the positively charged backbone of polyaniline (PANI). Such an adsorption helps in promoting the photodegradation of the dyes. It is interesting that although CoFe2O4 alone is an inactive visible-light-driven photocatalyst, the combination of CoFe2O4 nanoparticles with PANI leads to high photocatalytic activity for the degradation of the dyes under visible light irradiation. The dramatic enhancement in photoactivity can be attributed to the excited state electrons in PANI which can migrate to the conduction band (CB) of CoFe2O4, and the photogenerated holes in the valence band (VB) of CoFe2O4 which can directly transfer to the HOMO of PANI, effectively preventing a direct recombination of electrons and holes. Due to electrostatic repulsion, the cationic dyes containing positively charged groups cannot easily gain access to the positively charged backbone of PANI, giving very low photodegradation rates.

Transition-Metal-Free Direct Alkylation of Aryl Tetrazoles via Intermolecular Oxidative C–N Formation

A transition-metal-free synthetic approach for constructing alkylated aryl tetrazoles has been developed using n-Bu4NI as the catalyst and t-BuOOH as the oxidant. It involves the direct C-N bond formation through sp(3) C-H activation. A wide range of benzylic C-H substrates (or alkyl ethers) and aryl tetrazoles undergo this reaction smoothly to deliver the corresponding products in good yields.

ION-EXCHANGE RESIN–CATALYZED SYNTHESIS OF POLYOXYMETHYLENE DIMETHYL ETHERS: A PRACTICAL AND ENVIRONMENTALLY FRIENDLY WAY TO DIESEL ADDITIVE

Polyoxymethylene dimethyl ethers (PODEn) were synthesized via the reaction between dimethoxymethane (DMM) and trioxymethylene catalyzed by CT175, a macroporous strongly acidic cation-exchange resin. The influences of reaction conditions such as catalyst types, reaction temperature, time, pressure, catalyst dosage, and mass ratio of DMM to trioxymethylene were also investigated. Under the optimized conditions of m(dimethoxymethane):m(trioxymethylene) = 2.5:1, CT175 (7.5 wt.%), 90°C, 0.5 h, and 1.5 MPa, the conversion of trioxymethylene and the selectivity to PODE3-8 was obtained as high as 89.0% and 64.2%, respectively. Moreover, the resin catalyst can be reused up to 20 times without obvious change in its activity. The 100% atom efficiency, green reaction process, mild reaction conditions, as well as easy workup make the protocol advantageous and acceptable.

One-Pot Synthesis of 2,5-Diaryl 1,3,4-Oxadiazoles via Di-tert-butyl Peroxide Promoted N-Acylation of Aryl Tetrazoles with Aldehydes

A metal- and base-free protocol for one-pot synthesis of 2,5-diaryl 1,3,4-oxadiazoles via a radical-promoted cross-dehydrogenative coupling strategy was developed. This reaction involved the N-acylation of aryl tetrazoles with aryl aldehydes, followed by thermal rearrangement. A wide range of aryl tetrazoles and aryl aldehydes survived the reaction conditions to deliver the corresponding products in moderate to good yields.

Cogeneration of biodiesel and nontoxic rapeseed meal from rapeseed through in-situ alkaline transesterification.

In-situ alkaline transesterification of rapeseed oil with methanol for the production of biodiesel and nontoxic rapeseed meal was carried out. Water removal from milled rapeseed by methanol washing was more effective than vacuum drying. The conversion rate of rapeseed oil into FAME was 92%, FAME mass was 8.81 g, glucosinolates content in remaining rapeseed meal was 0.12% by methanol washing, while by vacuum drying the values were 46%, 4.44 g, 0.58%, respectively. In the presence of 0.10 mol/L NaOH in methanol, with methanol/oil molar ratio of 180:1 and a 3h reaction at 40 °C, a conversion rate of 98% was achieved, and the glucosinolates content was reduce to 0.07%, a value which below the GB/T 22514-2008 standard in China. Thus the rapeseed meal can be used as a source of protein in animal feed. The FAME prepared through in-situ alkaline transesterification met the ASTM specifications for biodiesel.

Solvent-mediated assembly of chiral/achiral hydrophilic Ca(II)-tetrafluoroterephthalate coordination frameworks: 3D chiral water aggregation, structural transformation and selective CO2 adsorption

The spontaneous self-assembly reactions of 2,3,5,6-tetrafluorobenzenedicarboxylic acid (H2BDC-F4) with Ca(NO3)2·4H2O in different solvents resulted in the generation of hydrophilic 3D chiral and achiral Ca(II)–organic frameworks {[Ca4(BDC-F4)4(H2O)4]·4H2O}n (1) and [Ca(BDC-F4)(MeOH)2]n (2), respectively. Complex 1 exhibits higher water solubility compared to 2, and further dissolution of 1 in water results in a new achiral crystal, [Ca(BDC-F4)(H2O)4]n (3). All complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal and powder X-ray diffraction techniques. Complex 1 crystallizes in the tetragonal P41212 chiral space group and features a rare binodal 5-connected network, directed by a unique 3D chiral (10,3)-a water aggregation consisting of two distinct helical arrays. Complex 2 crystallizes in the space group C2/c and has a binodal 4-connected pts net. Complex 3 crystallizes in the space group P21/m and presents a 2D layer framework containing the unprecedented polymeric [CaII–H2O]n chain based on triple μ2-O aqua bridges. The structural discrepancies illustrate the solvent-induced effect on the construction and structural transformation of chiral and achiral coordination frameworks. Moreover, gas (N2 and CO2) adsorption studies show that the dehydrated framework 1a exhibits excellent selective CO2 gas uptake at 195 K.

Regioselective 2,6-dihalogenation of BODIPYs in 1,1,1,3,3,3-hexafluoro-2-propanol and preparation of novel meso-alkyl polymeric BODIPY dyes

Regioselective 2,6-halogenation of BODIPYs in hexafluoro-2-propanol (HFIP) afforded products in less than 5 min. Halogenated BODIPYs were subjected to Pd-catalyzed cross-coupling reactions to form novel meso-alkyl polymeric BODIPY dyes.

Selective oxidation of sulfides to sulfoxides catalysed by deep eutectic solvent with H 2 O 2

A Brønsted acidic deep eutectic solvent based on choline chloride and p-toluenesulfonic acid (ChCl/p-TsOH, 1:1) was prepared and utilised for the selective oxidation of sulfides with H2O2 as the oxidant. Broad substrate compatibility, good yields and selectivities, the reusability of the catalyst as well as the gram-scale synthesis are the major advantages of this protocol. Moreover, the use of ChCl/p-TsOH, instead of neat p-TsOH, can greatly reduce the acid sewage especially in large-scale synthetic processes.

Alkali-metal-regulated construction of superhydrophilic ZnII and CdII coordination polymers with perhalogenated terephthalate ligands

By simply introducing different alkali metal ions as structure-directing agents, four new coordination polymers with the formulae [Cd3(BDC-F4)3(DMF)2(MeOH)6]n (1), [Cd(BDC-F4)(DMF)2(H2O)2]n (2), [Zn2Na2(BDC-Cl4)3(DMF)4(μ2-MeOH)]n (3) and [ZnK(BDC-Cl4)1.5(DMF)(Me2NH)]n (4) (BDC-F4 = 2,3,5,6-tetrafluoro-benzenedicarboxylate; BDC-Cl4 = 2,3,5,6-tetrachloro-benzenedicarboxylate; DMF = dimethylformamide and Me2NH = dimethylamine) have been synthesized and structurally characterized. Complex 1 presents an open three-dimensional (3D) 3-nodal (3,4)-connected framework, 2 has a one-dimensional (1D) chain structure, 3 features a 3D 4-nodal (3,4,5,6)-connected coordination network constructed from the new ZnII–NaI heterometallic tetranuclear cluster, and 4 shows a 3D 4-nodal (3,5,6)-connected network based on the unique ZnII–KI heterometallic tetranuclear cluster. The results reveal the significant influence of alkali-metal ions on the structural topologies of complexes 1–4. Interestingly, compounds 1–4 all exhibit high water solubility, and futher evaporation of their water solution will result in a 1D coordination polymer {[Cd4(BDC-F4)4(H2O)11]·3.5H2O}n (5) consisting of the unprecedented polymeric [CdII–H2O]n chain, and a zero-dimensional (0D) complex [Zn(H2O)6]·(BDC-Cl4)·4H2O (6) containing the discrete [Zn(H2O)6]2+ cationic and BDC-Cl4 dianionic moieties. Furthermore, the solution chemistry of complexes 5 and 6 has been investigated by electrospray ionization (ESI) mass spectrometry and molar electrical conductivity. The photoluminescent properties of complexes 1–6 have also been explored, which interestingly indicate a strong blue emission of complex 1 in the solid state at room temperature.

n-Bu4NI-catalyzed direct amination of ethers with aryl tetrazoles and triazoles via cross-dehydrogenative coupling reaction

An efficient, metal-free protocol for direct amination of ethers with aryl tetrazoles and triazoles has been developed using tetrabutylammonium iodide (TBAI) as a catalyst and tert-butyl hydroperoxide (t-BuOOH) as an oxidant. A series of ethers, aryl tetrazoles as well as triazoles are tolerated in this system, giving the corresponding products in moderate to good yields.