Catalytic Ammonia Oxidation to Dinitrogen by Hydrogen Atom Abstraction

Abstract

Scheme 2. a) Reaction of [Ru 15 NH 3 ] + with excess t Bu 3 ArOC;b)crossover experimentusing 14 NH 3 gas.

Activation of ammonia and hydrazine by electron rich Fe(ii) complexes supported by a dianionic pentadentate ligand platform through a common terminal Fe(iii) amido intermediate

“…S6 ‡ ), consistent with the other 15 NH 3 adducts previously reported. 8,9,26 The 11 B chemical spectrum also changes drastically from +38.4 ppm for complex 1Tol to −1.6 ppm for 1Tol-nNH3 , which is in the region of diamagnetic metal complexes with this ligand platform. 40 1Tol-nNH3 was isolated in 96% yield as a brown solid ( Scheme 2 ) and was characterized by single-crystal X-ray crystallography ( Fig.…”

“…While there have been several reports on heterogeneous catalysts for ammonia oxidation with limited success, 7 examples of homogeneous catalysts are attracting increasing attention. [8][9][10][11][12] Homogeneous catalysts offer the prospect of greater selectivity, more control over active site steric and electronic properties, and an opportunity to understand the fundamental chemistry involved through detailed spectroscopic and structural studies. 13 The oxidation of NH 3 into N 2 is an inherently challenging process due to the difficulty in breaking all three of its strong N-H bonds (the first N-H bond dissociation energy, BDE, of NH 3 is 107.6 kcal/mol), 14 as well as the multiple electron and proton transfers involved in the formation of N 2 (Scheme 1).…”

“…While there have been several reports on heterogeneous catalysts for ammonia oxidation with limited success, 7 examples of homogeneous catalysts are attracting increasing attention. 8–12 Homogeneous catalysts offer the prospect of greater selectivity, more control over active site steric and electronic properties, and an opportunity to understand the fundamental chemistry involved through detailed spectroscopic and structural studies. 13 …”

Origin of Stability and Inhibition of Cooperative Alkyne Hydrofunctionalization Catalysts

“…The donor-free complex [Ru(Cp*)(P tÀ Bu 2 N Ph 2 )]BAr F 4 (A) was recently reported by Mock and co-workers as the active catalyst for ammonia oxidation to give N 2 . [10] Two different isomers of A were characterized, which differed based on the coordination mode of the P tÀ Bu 2 N Ph 2 ligand (Figure 2a). A low-coordinate isomer k 2 -(P,P)-A with a bidentate P tÀ Bu 2 N Ph 2 mode was observed in both the solution and solid state.…”

Chemical and Electrocatalytic Ammonia Oxidation by Ferrocene

“…18,19 Transition metal complexes stoichiometrically convert ammonia to nitrogen in the presence of appropriate oxidants 20,21 or under electrochemical forcing, 22 while a molybdenum complex releases hydrogen from bound ammonia under mild conditions. 23 Coupling these steps, a molecular complex based on the precious metal ruthenium catalyzes the electrolysis of NH 3 to N 2 and H 2 ( Fig. 1A).…”