Promising hydrogen storage properties and potential applications of Mg-Al-Pd trilayer films under mild conditions

We prepared a series of nano-sized Mg-Al-Pd trilayer films and investigated their hydrogen storage properties under mild conditions. Results showed that Al 1 nm sample had the best absorption kinetics and excellent optical properties at room temperature, making it a promising candidate for hydrogen sensors and smart windows.     

Polymerized surface micelles formed under mild conditions

A new polymerizable surfactant 1-[11-(lipoyloxy)-undecyl]-pyridinium bromide was synthesized, which provides a new approach for polymerizing micelles under mild conditions.     

Catalytic methanolysis of hydrazine borane: a new and efficient hydrogen generation system under mild conditions

Safe and efficient hydrogen storage is a major obstacle for using hydrogen as an energy carrier. Therefore, intensive efforts have been focused on the development of new materials for chemical hydrogen storage. Of particular importance, hydrazine borane (N(2)H(4)BH(3)) is emerging as one of the most promising solid hydrogen carriers due to its high gravimetric hydrogen storage capacity (15.4 wt%) and low molecular weight. Herein, we report metal catalyzed methanolysis of hydrazine borane (N(2)H(4)BH(3), HB) as a fast hydrogen generation system under mild conditions. When trace amounts of nickel(ii) chloride (NiCl(2)) is added to the methanol solution of hydrazine borane ([HB]/[Ni] ≥ 200) the reaction solution releases 3 equiv. of H(2) with a rate of 24 mol H(2) (mol Ni min)(-1) at room temperature. The results reported here also includes (i) identification of the reaction products by using ATR-IR, DP-MS, (1)H and (11)B NMR spectroscopic techniques and the establishment of the reaction stoichiometry, (ii) investigation of the effect of substrate and catalyst concentrations on the hydrogen generation rate to determine the rate law for the catalytic methanolysis of hydrazine borane, (iii) determination of the activation parameters (E(a), ΔH(#), and ΔS(#)) for the catalytic methanolysis of hydrazine borane by using the temperature dependent rate data of the hydrogen generation.     

Hydrogen bond activated glycosylation under mild conditions

Herein, we report a new glycosylation system for the highly efficient and stereoselective formation of glycosidic bonds using glycosyl N-phenyl trifluoroacetimidate (PTFAI) donors and a charged thiourea hydrogen-bond-donor catalyst. The glycosylation protocol features broad substrate scope, controllable stereoselectivity, good to excellent yields and exceptionally mild catalysis conditions. Benefitting from the mild reaction conditions, this new hydrogen bond-mediated glycosylation system in combination with a hydrogen bond-mediated aglycon delivery system provides a reliable method for the synthesis of challenging phenolic glycosides. In addition, a chemoselective glycosylation procedure was developed using different imidate donors (trichloroacetimidates, N-phenyl trifluoroacetimidates, N-4-nitrophenyl trifluoroacetimidates, benzoxazolyl imidates and 6-nitro-benzothiazolyl imidates) and it was applied for a trisaccharide synthesis through a novel one-pot single catalyst strategy.

A mild glycosylation system was developed using glycosyl imidate donors and a charge-enhanced thiourea H-bond donor catalyst. The method can be used for the effective synthesis of O-, C-, S- and N-glycosides and chemoselective one-pot glycosylation.     

Copper-catalyzed sonogashira-type reactions under mild palladium-free conditions

We have developed an inexpensive catalytic system using a readily available copper/ligand combination for the Sonogashira-type cross-coupling of aryl iodides and phenyl- and hexyl-acetylene which affords disubstituted alkynes in good to excellent yields.     

Rearrangement of indene skeletons under mild conditions

Isomerization between two isomers of 1,2-disubstituted 3-aminoindenes occurs via the rearrangement of indene frameworks. In contrast to previous rearrangements of indene derivatives, which occur under high-temperature conditions or the irradiation of light, this rearrangement proceeds at room temperature without UV light irradiation. An amino group at the 3-position plays an important role to accelerate the rearrangement under mild conditions.     

High efficient iron-catalyzed transfer hydrogenation of quinolines with Hantzsch ester as hydrogen source under mild conditions

A highly efficient transfer hydrogenation of quinolines with Hantzsch ester as hydrogen source in the presence of 1 mol% Fe(OTf)₂ under mild conditions has been developed. A series of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields with good functional group tolerance.     

Synthesis of tetraphenylporphyrins under very mild conditions

Reaction of pyrrole and an aromatic aldehyde at room temperature affords the corresponding tetraarylporphyrinogen in high yield at thermodynamic equilibrium. Oxidation yields the porphyrin. The reaction conditions are of broad scope.     

NQR of hydrogen bonded crystals under high pressure

The work presents the results of NQR under high hydrostatic pressure for the following ferroelectrics: KDA, KD^xA, LHA, LDA and AHCA. Most of the below presented discussions concerns the behaviour of these ferroelectrics and the explanation of this behaviour on the basis of pseudo-spin-lattice coupling model.     

Cyclization under mild conditions of cysteine containing peptides

Cyclization of di- and tripeptides containing cysteine as N-terminal residue is reported. The preferred cyclization patterns and the nature of the products (diketopiperazine, aza-cyclol, peptide thiolactone) are discussed.     

Tellurium-mediated cycloaromatization of acyclic enediynes under mild conditions

The cycloaromatization of acyclic enediynes typically requires very high temperatures (>160 degrees C) and dilute conditions to proceed in a synthetically useful yield. These conditions hinder reaction throughput, inhibiting the use of this reaction for the large-scale production of materials. The reaction of sodium telluride with acyclic arenediynes yields the corresponding tellurepine, which under gentle heating extrudes Te degrees to yield the cycloaromatization product. We have developed conditions that form sodium telluride from inexpensive tellurium metal in situ, and that also perform the desilylation of silylated arenediynes in the same process. Under our conditions, we are able to perform desilylation and cycloaromatization at temperatures as low as 40 degrees C and on a scale as large as 5 g in standard laboratory glassware.     

Facile synthesis of urea derivatives under mild conditions

Urea derivatives were readily synthesized in good yields under quite mild conditions, i.e., at ambient pressure and room temperature by sulfur-assisted carbonylation of primary amines with carbon monoxide followed by oxidation of the resulting ammonium thiocarbamates with molecular oxygen.     

温和条件下氢化锂的催化合成

本文提出了一种温和条件下合成氢化锂的方法,催化剂是由萘或萘的甲基衍生物和TiCl4组成,具有很高的活性。它可以使金属锂在25-50℃常压加氢,根据催化剂的不同组成,锂可以在2～5小时内定量地转化成氢化锂,考察了催化剂的稳定性,并确定了催化剂组成和控制反应步骤之间的关系。     

Selective oxidation of light alkanes under mild conditions

Methanotrophs mediate the conversion of methane (CH₄) into methanol selectively and efficiently near ambient conditions so we can learn from microbes to develop biomimetic catalysts capable of performing this difficult chemistry. This review highlights the development of a tricopper cluster catalyst that functions similar to the particulate methane monooxygenase enzyme in methanotrophic bacteria. The performance of this catalytic system formulated for quasi-heterogeneous catalysis is compared with other heterogeneous catalysts derived from Cu- and Fe-based zeolites and Cu mordenites known to activate CH₄ stoichiometrically near 200 °C. We also highlight a unique catalytic system, in which the oxidizing power of both O atoms of the O₂ molecule can be harnessed for oxidation of toluene to yield benzaldehyde at room temperature.     

Beckmann rearrangement of oximes under very mild conditions

A variety of ketoximes, easily prepared from the corresponding ketones, undergo the Beckmann rearrangement upon treatment with 2,4,6-trichloro[1,3,5]triazine in N,N-dimethylformamide at room temperature in excellent yields. This procedure can be applied to aldoximes for obtaining the corresponding nitriles.