Development of a Mixed Multinuclear Cluster Strategy in Metal-Organic Frameworks for Methane Purification and Storage.

Metal-organic frameworks (MOFs) have attracted extensive attention in methane (CH4) purification and storage. Specially, multinuclear cluster-based MOFs usually have prominent performance because of large cluster size and abundant open metal sites. However, compared to diverse combinations of organic linkers, one MOF with two or more multinuclear clusters is difficult to achieve. In this paper, we demonstrate a mixed multinuclear cluster strategy, which successfully led to three new heterometallic MOFs (SNNU-328-330) with the same common H3TATB [2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine] tritopic linker and six types of multinuclear clusters ([YCd(COO)4(µ2-H2O)], [YCd2(COO)8], [In3(COO)6(µ3-OH)], [In3Eu2(COO)9(µ3-OH)3(µ4-O)], [Y9(COO)12(µ3-OH)14] and [Y2Cd8(COO)16(µ2-H2O)4(µ3-OH)8]). Three MOF adsorbents all show great potentials to remove the impurities (CO2 and C2-hydrocarbons) in natural gas and show prominent high-pressure methane storage capacity. Among them, the ideal adsorbed solution theory separation ratios of equimolar C2H2/CH4, C2H4/CH4, C2H6/CH4, and CO2/CH4 at 298 K for SNNU-328 reach to 29.7-16.0, 19.1-8.2, 33.2-10.3, and 74.3-8.5, which have surpassed many famous MOF adsorbents. Dynamic breakthrough experiments conducted at 273 and 298 K showed that SNNU-330 can separate CH4 from C2H2/CH4, C2H4/CH4, C2H6/CH4, and CO2/CH4 mixtures with the breakthrough interval times of about 48.2, 17.9, 37.2, and 17.1 min g-1 (273 K, 1 bar, v/v = 50/50, 2 mL min-1), respectively. Remarkably, SNNU-329 exhibits extremely high methane storage performance at 298 K with the total uptake and working capacity of 192 cm3 cm-3 (95 bar) and 171 cm3 cm-3 (65 bar) due to the synergistic effects of high surface area, suitable pore sizes, and multiple open metal sites.

Combined inoculation with dark septate endophytes and arbuscular mycorrhizal fungi: synergistic or competitive growth effects on maize?

BACKGROUND: Effects on maize were assessed of dual inoculation with arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) isolated from other plant species. METHODS: Suspensions of DSE isolated from Stipa krylovii were prepared at different densities (2, 4, and 8 × 105 CFU mL- 1) and inoculated separately (AMF or DSE) or together (AMF + DSE), to explore their effects on maize growth. RESULTS: Inoculation with AMF or medium and high densities of DSE and combined inoculation (AMF + DSE) increased plant above-ground growth and altered root morphology. Differences in plant growth were attributable to differences in DSE density, with negative DSE inoculation responsiveness at low density. AMF promoted plant above-ground growth more than DSE and the high density of DSE promoted root development more than AMF. Combined inoculation might lead to synergistic growth effects on maize at low density of DSE and competitive effects at medium and high DSE densities. CONCLUSIONS: AMF and DSE co-colonized maize roots and they had positive effects on the host plants depending on DSE density. These findings indicate the optimum maize growth-promoting combination of AMF and DSE density and provide a foundation for further exploration of potentially synergistic mechanisms between AMF and DSE in physiological and ecological effects on host plants.

Catalytic Fast Pyrolysis of Tar-Rich Coal with a Bauxite Residue for Upgrading High-Value Products: Product Distribution and Kinetic Analysis.

Fast pyrolysis technology can reduce the secondary reactions, improve the volatile product yield, and reduce the semicoke yield. Still, the high proportion of heavy tar components affects the development of fast pyrolysis industrialization. Therefore, this paper put forward a catalytic upgrading method of coal based on the solid waste bauxite residue (BR) as a catalyst. This study investigated the impact of varying particle sizes of pulverized coal and the addition of the BR catalyst on the product distribution and kinetics of coal fast pyrolysis. The results found that the tar yield was the highest at 600 °C when the particle size of pulverized coal was 75-150 µm, which was 19.44%. In the range of 550-650 °C, the relative content of benzene and toluene xylene (BTX) in liquid products increased with the temperature. With the increase of the proportion of the BR catalyst, the yield of semicoke in coal pyrolysis products increased, the yield of the gas phase also increased, and the yield of the liquid phase decreased.

An α-diiminato germylene family: syntheses, structures, and reactivity towards C-C coupled digermylene and digermylene oxide.

The synthesis and reactivity of a rigid α-diiminate ligand supported chlorogermylene 2 were demonstrated. The reaction of 2 with hydride donor K[BH(sBu)3] yielded a hydride addition product, a five-membered 6π-aromatic germylene 3. A nonaromatic germylene 4 was produced by dehydrochlorination of 2 with KN(SitBuMe2)2. Halide abstraction with AlCl3 from 2 afforded a cationic germylene 5, and the reduction of 2 with potassium led to a C-C coupled digermylene 6via a radical coupling pathway. Hydrolysis of 2 in the presence of NHC ((tBu-NCH)2C:) gave digermylene oxide 7. DFT investigations of central GeII-rings in molecules 3-5 provided the details of frontier molecular orbitals. The energy level of the lone pair on the Ge atom in 3 is slightly higher than that in 4, indicating that 3 is the stronger σ-donor than 4. Digermylene 6 and its diastereoisomer 6a feature trans-bent and gauche-bent configurations along their axially chiral C-C bonds, respectively. The conformational and cis-trans isomerism was observed by the isolation of crystal structures 7 and 7a because of intramolecular steric hindrance.