Bypassing Ammonia: From N to Nitrogen Heterocycles without N Intermediates or Transition Metals.

Diboradiazene compounds, derived in one step from the boron-mediated reduction of dinitrogen (N), were treated separately with sulfur and acetic anhydride, providing heterocyclic compounds that are BN isosteres of thiophene and 1,3-oxazole, respectively. These simple reactions represent the final steps in two-step routes to complex heterocycles from N that both circumvent the need for transition metal reagents and completely bypass the traditional intermediate ammonia.

Ca-Ag compounds in ethylene epoxidation reaction.

The ethylene epoxidation is a challenging catalytic process, and development of active and selective catalyst requires profound understanding of its chemical behaviour under reaction conditions. The systematic study on intermetallic compounds in the Ca-Ag system under ethylene epoxidation conditions clearly shows that the character of the oxidation processes on the surface originates from the atomic interactions in the pristine compound. The Ag-rich compounds CaAg and CaAg undergo oxidation towards Ag and a complex Ca-based support, whereas equiatomic CaAg and the Ca-rich compounds CaAg and CaAg in bulk remain stable under harsh ethylene epoxidation conditions.

Anisotropic Reactivity of CaAg under Ethylene Epoxidation Conditions.

The chemical behavior of CaAg as catalyst for ethylene epoxidation was studied using a combination of experimental (X-ray powder diffraction, scanning electron microscopy, thermal analysis and infrared spectroscopy), and quantum chemical techniques as well as real-space chemical bonding analysis. Under oxidative ethylene epoxidation conditions, the CaAg (010) surface possesses an outstanding stability during long-term experiments. It is caused by the formation of an ordered, stable and dense CaO passivation layer with a small amount of embedded Ag atoms.

Synthesis of PtY and Other Early-Late Intermetallic Nanoparticles by Way of a Molten Reducing Agent.

Early-late intermetallic phases have garnered increased attention recently for their catalytic properties. To achieve the high surface areas needed for industrially relevant applications, these phases must be synthesized as nanoparticles in a scalable fashion. Herein, PtY-targeted as a prototypical example of an early-late intermetallic-has been synthesized as nanoparticles approximately 5-20 nm in diameter via a solution process and characterized by XRD, TEM, EDS, and XPS.