Reduction of N2 by H2 to NH3 and N2H4 using [MoL] (L = triamidoamine) and organic co-catalysts: A theoretical approach

A new methodology is proposed and tested by Density Functional Theory (DFT) calculations to reduce N2 to NH3 and N2H4 using H2 in the presence of [Mo{(NHCH2CH2)3N}] and organic co-catalysts under mild experimental conditions. The calculated Gibbs free energies of the fundamental reactions to form various intermediates and transition state molecules suggest that the proposed catalytic cycle is viable to produce NH3 and N2H4, however NH3 formation is more feasible than N2H4. Formation of six coordinate [Mo]-H intermediates have also been predicted. The direct contact of H2 with [N2-Mo{(NHCH2CH2)3N}] catalyst can be avoided by using organic co-catalysts to prevent the competition in binding between N2 and H2 with [Mo{(NHCH2CH2)3N}] catalyst.

Graphical abstractA new strategy has been proposed and tested by DFT calculations for the reduction of N2 to NH3 and N2H4 by H2 under normal experimental condition using [N2-Mo{(NHCH2CH2)3N}] catalyst. The calculated reaction Gibbs free energy profile indicates that the proposed methodology is viable. The direct contact of H2 with Schrock catalyst can be avoided by using organic co-catalysts to prevent the competition in binding between N2 and H2.Figure optionsDownload full-size imageDownload high-quality image (137 K)Download as PowerPoint slideHighlights► A new strategy has been proposed for the reduction of N2 to NH3 and N2H4 by H2. ► The calculated free energies show that the formation NH3 is more viable than the N2H4. ► Formation of six coordinate [Mo]-H intermediates have also been predicted. ► The direct contact of H2 with [N2-Mo{(NHCH2CH2)3N}] catalyst can be avoided.