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This content will become publicly available on September 20, 2017

Title: Dimension and bridging ligand effects on Mo-mediated catalytic transformation of dinitrogen to ammonia: Chain-like extended models of Nishibayashi’s catalyst

Previous studies suggested that in Nishibayashi’s homogenous catalytic systems based on molybdenum (Mo) complexes, the bimetallic structure facilitated dinitrogen to ammonia conversion in comparison to the corresponding monometallic complexes, likely due to the through-bond interactions between the two Mo centers. However, more detailed model systems are necessary to support this bimetallic hypothesis, and to elucidate the multi-metallic effects on the catalytic mechanism. In this work, we computationally examined the effects of dimension as well as the types of bridging ligands on the catalytic activities of molybdenum-dinitrogen complexes by using a set of extended model systems based on Nishibayashi’s bimetallic structure. The polynuclear chains containing four ([Mo]4) or more Mo centers were found to drastically enhance the catalytic performance by comparing with both the monometallic and bimetallic complexes. Carbide ([:C≡C:]2–) was found to be a more effective bridging ligand than N2 in terms of electronic charges dispersion between metal centers thereby facilitating reactions in the catalytic cycle. Furthermore, the mechanistic modelling suggests that in principle, more efficient catalytic system for N2 to NH3 transformation might be obtained by extending the polynuclear chain to a proper size in combination with an effective bridging ligand for charge dispersion.
Authors:
 [1] ;  [2] ;  [1] ;  [1]
  1. Sichuan Univ., Shichuan (People's Republic of China)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1329598
Report Number(s):
LA-UR--16-24481
Journal ID: ISSN 2210-271X
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Computational and Theoretical Chemistry
Additional Journal Information:
Journal Volume: 1095; Journal Issue: C; Journal ID: ISSN 2210-271X
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
LDRD; USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY ammonia production; N2 to NH3; DFT; homogeneous catalysis; nitrogen fixation; catalysis; molybdenum complex; polynuclear model