Silicon Clathrate-Supported Catalysts with Low Work Functions for Ammonia Synthesis.

Diamond-type silicon has a work function of ≈4.8 eV, and conventional n- or p-type doping modifies the value only between 4.6 and 5.

Ruthenium Complexes for Catalytic Dehydrogenation of Hydrazine and Transfer Hydrogenation Reactions.

Catalytic dehydrogenation of hydrazine was achieved over iminopyridine ligated ruthenium-arene complexes, where the release of H gas, as confirmed by GC-TCD, from hydrazine depends on reaction temperature, base, and solvents. NMR and MS studies indicated an in situ generation of a hydrazine-coordinated ruthenium species, a key intermediate of hydrazine dehydrogenation, via a coordination-assisted activation pathway.

Core-Shell Zeolitic Imidazolate Frameworks for Enhanced Hydrogen Storage.

Core-shell ZIF-8@ZIF-67- and ZIF-67@ZIF-8-based zeolitic imidazolate frameworks (ZIFs) were synthesized solvothermally using a seed-mediated methodology. Transmission electron microscopy-energy-dispersive X-ray spectrometry, line scan, elemental mapping, X-ray photoelectron spectroscopy, and inductively coupled plasma-atomic emission spectroscopy analyses were performed to confirm the formation of a core-shell structure with the controlled Co/Zn elemental composition of ∼0.50 for both the core-shell ZIFs.

C-H Bond Activation/Arylation Catalyzed by Arene-Ruthenium-Aniline Complexes in Water.

Water-soluble arene-ruthenium complexes coordinated with readily available aniline-based ligands were successfully employed as highly active catalysts in the C-H bond activation and arylation of 2-phenylpyridine with aryl halides in water. A variety of (hetero)aryl halides were also used for the ortho-C-H bond arylation of 2-phenylpyridine to afford the corresponding ortho- monoarylated products as major products in moderate to good yields. Our investigations, including time-scaled NMR spectroscopy and mass spectrometry studies, evidenced that the coordinating aniline-based ligands, having varying electronic and steric properties, had a significant influence on the catalytic activity of the resulting arene-ruthenium-aniline-based complexes.

Ruthenium-Catalyzed Oxidative Homocoupling of Arylboronic Acids in Water: Ligand Tuned Reactivity and Mechanistic Study.

Molecular catalysts based on water-soluble arene-Ru(II) complexes ([Ru]-1-[Ru]-5) containing aniline (L1), 2-methylaniline (L2), 2,6-dimethylaniline (L3), 4-methylaniline (L4), and 4-chloroaniline (L5) were designed for the homocoupling of arylboronic acids in water. These complexes were fully characterized by (1)H, (13)C NMR, mass spectrometry, and elemental analyses. Structural geometry for two of the representative arene-Ru(II) complexes [Ru]-3 and [Ru]-4 was established by single-crystal X-ray diffraction studies.

Direct vs. indirect pathway for nitrobenzene reduction reaction on a Ni catalyst surface: a density functional study.

Density functional theory (DFT) calculations are performed to understand and address the previous experimental results that showed the reduction of nitrobenzene to aniline prefers direct over indirect reaction pathways irrespective of the catalyst surface. Nitrobenzene to aniline conversion occurs via the hydroxyl amine intermediate (direct pathway) or via the azoxybenzene intermediate (indirect pathway). Through our computational study we calculated the spin polarized and dispersion corrected reaction energies and activation barriers corresponding to various reaction pathways for the reduction of nitrobenzene to aniline over a Ni catalyst surface.

Room-temperature chemoselective reduction of nitro groups using non-noble metal nanocatalysts in water.

Purely aqueous-phase chemoselective reduction of a wide range of aromatic and aliphatic nitro substrates has been performed in the presence of inexpensive Ni- and Co-based nanoparticle catalysts using hydrazine hydrate as a reducing agent at room temperature. Along with the observed high conversions and selectivities, the studied nanoparticle catalysts also exhibit a high tolerance to other highly reducible groups present in the nitro substrates. The development of these potential chemoselective reduction catalysts also provides a facile route for the synthesis of other industrially important fine chemicals or biologically important compounds, where other highly reducible groups are present in close proximity to the targeted nitro groups.