Ruihu Wang

Bis[3-(5-nitroimino-1,2,4-triazolate)]-Based Energetic Salts: Synthesis and Promising Properties of a New Family of High-Density Insensitive Materials

Bis[3-(5-nitroimino-1,2,4-triazolate)]-based energetic salts were synthesized in a simple, straightforward manner. They exhibit low solubility in available solvents, high hydrolytic stability, excellent thermal stability, high density, positive heat of formation, low shock sensitivity, and excellent detonation properties. The physical and energetic properties of some salts are similar and even superior to those of RDX.

A new type of three-dimensional framework constructed from dodecanuclear cadmium(ii) macrocyclesElectronic supplementary information (ESI) available: Synthesis of 1 Figures S1‒S4. See http://www.rsc.org/suppdata/cc/b2/b212425d/This work was supported by the National Nature Science Foundation of China, Nature Science Foundation of Fujian Province and the Key Project of Chinese Academy of Science.

A new type of three-dimensional framework based on dodecanuclear Cd(II) macrocycles [[Cd2(dpa)(pya)]6(pya)6(dpe)3]n (1) (H2dpa = diphenic acid; Hpya = isonicotinic acid, dpe = 1,2-di(4-pyridyl)ethylene) was prepared by the hydrothermal reaction and in situ synthesis of pya from dpe precursor.

Furazan‐Functionalized Tetrazolate‐Based Salts: A New Family of Insensitive Energetic Materials

Insensitive energetic salts: A series of furazan-functionalized tetrazolate-based energetic salts (see figure) were synthesized and characterized. All of the salts exhibit excellent thermal stabilities and high positive heats of formation.Furazan-functionalized tetrazolate-based energetic salts (1-13) were prepared by direct treatment of neutral 4-amino-3-(5-tetrazole)furazan and a Lewis base or by simple metathesis reactions of its barium salt formed in situ with the corresponding sulfate salts in aqueous solution. Key physical properties, such as melting point, thermal stability, density, hypergolicity, and sensitivity to shock, were measured. The relationship between their structures and these properties was determined. Most of salts exhibit better thermal stability than their 5-nitrotetrazolate and 5-nitraminotetrazolate analogues as well as other furazan-based salts. The structures of representative aminoguanidinium (4), carbonic hydrazylhydrazidinium (9), and 1,4-dimethyl-5-aminotetrazolium salts (13) were further confirmed by single-crystal X-ray analysis. Their densities, heats of formation, detonation pressures and velocities, and specific impulses were calculated. All of the salts possess high positive heats of formation. The effect of the furazan ring on these physicochemical properties was examined and discussed.

Facile Fabrication of Ultrafine Palladium Nanoparticles with Size- and Location-Control in Click-Based Porous Organic Polymers

Two click-based porous organic polymers (CPP-1 and CPP-2) are readily synthesized through a click reaction. Using CPP-1 and CPP-2 as supports, palladium nanoparticles (NPs) with uniform and dual distributions were prepared through H2 and NaBH4 reduction routes, respectively. Ultrafine palladium NPs are effectively immobilized in the interior cavities of polymers. The coordination of 1,2,3-triazolyl to palladium and the confinement effect of polymers on palladium NPs are verified by solid-state (13)C NMR and IR spectra, XPS analyses, EDX mapping, and computational calculation. The steric and electronic properties of polymers have a considerable influence on the interaction between polymers and palladium NPs, as well as the catalytic performances of NPs. The ultrafine palladium NPs with uniform distribution exhibit superior stability and recyclability over palladium NPs with dual distributions and palladium on charcoal in the hydrogenation of nitroarenes, and no obvious agglomeration and loss of catalytic activity were observed after recycling several times. The excellent performances mainly result from synergetic effects between palladium NPs and polymers.

Hybrid Nanocarbon as a Catalyst for Direct Dehydrogenation of Propane: Formation of an Active and Selective Core–Shell sp2/sp3 Nanocomposite Structure

Hybrid nanocarbon, comprised of a diamond core and a graphitic shell with a variable sp(2)-/sp(3)-carbon ratio, is controllably obtained through sequential annealing treatment (550-1300 °C) of nanodiamond. The formation of sp(2) carbon increases with annealing temperature and the nanodiamond surface is reconstructed from amorphous into a well-ordered, onion-like carbon structure via an intermediate composite structure--a diamond core covered by a defective, curved graphene outer shell. Direct dehydrogenation of propane shows that the sp(2)-/sp(3)-nanocomposite exhibits superior catalytic performance to that of individual nanodiamond and graphitic nanocarbon. The optimum catalytic activity of the diamond/graphene composite depends on the maximum structural defectiveness and high chemical reactivity of the ketone groups. Ketone-type functional groups anchored on the defects/vacancies are active for propene formation; nevertheless, once the oxygen functional groups are desorbed, the defects/vacancies alone might be active sites responsible for the C-H bond activation of propane.

Pyrazolyl-functionalized 2-methylimidazolium-based ionic liquids and their palladium(II) complexes as recyclable catalysts.

A series of pyrazolyl- and 3,5-dimethylpyrazolyl-functionalized 2-methylimidazolium-based salts have been prepared through neat reactions of 1-pyrazolylmethylene-2-methylimidazole and 1-(3,5-dimethylpyrazolylmethylene)-2-methylimidazole with alkyl or polyfluoroalkyl iodides or 1-bromohexane, followed by anion exchange with LiN(SO2CF3)2 or KPF6. Their thermal properties were determined by DSC and TGA. Most of the bis(trifluoromethanesulfonyl)amide salts are room temperature ionic liquids. The influence of anions and of the structural variation in the 2-methylimidazolium-based cations on the physicochemical properties is discussed. These salts reacted easily with palladium(II) chloride to generate mononuclear palladium ionic liquid complexes. The catalytic activity and recyclability of the palladium complexes in the corresponding ionic liquids were preliminarily examined using Heck, Suzuki and Sonogashira cross-coupling reactions in the absence of phosphine ligands.

Syntheses and characterizations of two novel Ln(III)–Cu(II) coordination polymers constructed by Pyridine-2,4-dicarboxylate ligand

Abstract Two novel three dimension Ln(III)–Cu(II) coordination polymers [Gd 2 Cu(pydc) 4 (H 2 O) 6 ] n and [Sm 2 Cu 3 (pydc) 6 (H 2 O) 6 ] n were prepared by the hydrothermal reactions of CuO, Ln 2 O 3 (Ln = Gd, Sm), H 2 pydc (H 2 pydc = 2,4-pyridinedicarboxylic acid) and characterized by single-crystal X-ray diffraction analysis.

Efficient Heck reactions catalyzed by a highly recyclable palladium(II) complex of a pyridyl-functionalized imidazolium-based ionic liquid†

The reactions of 2-(2-pyridyl)imidazole with alkyl iodides at 25 degrees C in the presence of base gave rise to 1-alkyl-2-(2-pyridyl)imidazole. Subsequent neat reactions with alkyl or polyfluoroalkyl halides at 100 degrees C, followed by anion exchange with LiN(SO(2)CF(3))(2), generated the mono-quaternary ionic liquids. All of them have excellent thermal stability and wide liquid range. Most of the salts with asymmetric N-substituents are liquid at room temperature. The effect of N-substituent variation and symmetry on NMR, TGA and DSC is discussed. Reaction of with palladium(II) chloride produced a mononuclear palladium ionic liquid complex, the structure of which was confirmed by single-crystal X-ray diffraction analysis. The Heck cross-coupling reactions using in ionic liquid demonstrated excellent stability and recyclability.

Bipyridyl-based diphosphine as an efficient ligand in the rhodium-catalyzed asymmetric conjugate addition of arylboronic acids to α,β-unsaturated ketones

Abstract Reactions of α,β-unsaturated ketones with excess arylboronic acids in the presence of a rhodium catalyst generated in situ from Rh(acac)(C 2 H 4 ) and ( S )-P-Phos in dioxane/water at 100°C gave high yields of the corresponding products in up to 99% ee.

Designed Assembly of Heterometallic Cluster Organic Frameworks Based on Anderson-Type Polyoxometalate Clusters.

A new approach to prepare heterometallic cluster organic frameworks has been developed. The method was employed to link Anderson-type polyoxometalate (POM) clusters and transition-metal clusters by using a designed rigid tris(alkoxo) ligand containing a pyridyl group to form a three-fold interpenetrated anionic diamondoid structure and a 2D anionic layer, respectively. This technique facilitates the integration of the unique inherent properties of Anderson-type POM clusters and cuprous iodide clusters into one cluster organic framework.