US EPA

4836676 

Journal Article 

NH3 Synthesis in the N2/H2 Reaction System using Cooperative Molecular Tungsten/Rhodium Catalysis in Ionic Hydrogenation: A DFT Study 

Moha, V; Leitner, W; Hölscher, M 

2016 

Yes 

Chemistry: A European Journal
ISSN: 0947-6539
EISSN: 1521-3765 

22 

8 

2624-2628 

English 

26711865 

10.1002/chem.201504660 

WOS:000370193000012 

The ionic hydrogenation of N2 with H2 to give NH3 is investigated by means of density functional theory (DFT) computations using a cooperatively acting catalyst system. In this system, N2 binds to a neutral tungsten pincer complex of the type [(PNP)W(N2)3] (PNP=pincer ligand) and is reduced to NH3. The protons and hydride centers necessary for the reduction are delivered by heterolytic cleavage of H2 between the N2-tungsten complex and the cationic rhodium complex [Cp*Rh{2-(2-pyridyl)phenyl}(CH3 CN)](+). Successive transfer of protons and hydrides to the bound N2, as well as all Nx Hy units that occur during the reaction, enable the computation of closed catalytic cycles in the gas and in the solvent phase. By optimizing the pincer ligands of the tungsten complex, energy spans as low as 39.3 kcal mol(-1) could be obtained, which is unprecedented in molecular catalysis for the N2/H2 reaction system.