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Title: The Mechanism of N–N Double Bond Cleavage by an Iron(II) Hydride Complex

The use of hydride species for substrate reductions avoids strong reductants, and may enable nitrogenase to reduce multiple bonds without unreasonably low redox potentials. Here in this work, we explore the N=N bond cleaving ability of a high-spin iron(II) hydride dimer with concomitant release of H 2. Specifically, this diiron(II) reacts with azobenzene (PhN=NPh) to perform the fourelectron reduction to two imido groups, where two electrons come from H 2 reductive elimination and the other two come from iron oxidation. The rate law of the H 2 releasing reaction indicates that diazene binding occurs prior to H 2 elimination, and the negative entropy of activation and inverse kinetic isotope effect indicate that H-H bond formation is the rate-limiting step. Thus, substrate binding causes reductive elimination of H 2 that formally reduces the metals, and the metals use the additional two electrons to cleave the N-N multiple bond.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [5] ;  [6]
  1. Univ. of Rochester, NY (United States). Dept. of Chemistry
  2. Yale Univ., New Haven, CT (United States). Dept. of Chemistry
  3. Univ. of Rochester, NY (United States). Dept. of Chemistry; Rani Channamma Univ., Vidyasangama, Belagavi (India)
  4. Max Planck Inst. for Chemical Energy Conversion, Mülheim an der Ruhr (Germany)
  5. Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry and CASCaM
  6. Univ. of Rochester, NY (United States). Dept. of Chemistry; Yale Univ., New Haven, CT (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
FG02-03ER15387
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 138; Journal Issue: 37; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of North Texas, Denton, TX (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1467439

Bellows, Sarina M., Arnet, Nicholas A., Gurubasavaraj, Prabhuodeyara M., Brennessel, William W., Bill, Eckhard, Cundari, Thomas R., and Holland, Patrick L.. The Mechanism of N–N Double Bond Cleavage by an Iron(II) Hydride Complex. United States: N. p., Web. doi:10.1021/jacs.6b04654.
Bellows, Sarina M., Arnet, Nicholas A., Gurubasavaraj, Prabhuodeyara M., Brennessel, William W., Bill, Eckhard, Cundari, Thomas R., & Holland, Patrick L.. The Mechanism of N–N Double Bond Cleavage by an Iron(II) Hydride Complex. United States. doi:10.1021/jacs.6b04654.
Bellows, Sarina M., Arnet, Nicholas A., Gurubasavaraj, Prabhuodeyara M., Brennessel, William W., Bill, Eckhard, Cundari, Thomas R., and Holland, Patrick L.. 2016. "The Mechanism of N–N Double Bond Cleavage by an Iron(II) Hydride Complex". United States. doi:10.1021/jacs.6b04654. https://www.osti.gov/servlets/purl/1467439.
@article{osti_1467439,
title = {The Mechanism of N–N Double Bond Cleavage by an Iron(II) Hydride Complex},
author = {Bellows, Sarina M. and Arnet, Nicholas A. and Gurubasavaraj, Prabhuodeyara M. and Brennessel, William W. and Bill, Eckhard and Cundari, Thomas R. and Holland, Patrick L.},
abstractNote = {The use of hydride species for substrate reductions avoids strong reductants, and may enable nitrogenase to reduce multiple bonds without unreasonably low redox potentials. Here in this work, we explore the N=N bond cleaving ability of a high-spin iron(II) hydride dimer with concomitant release of H2. Specifically, this diiron(II) reacts with azobenzene (PhN=NPh) to perform the fourelectron reduction to two imido groups, where two electrons come from H2 reductive elimination and the other two come from iron oxidation. The rate law of the H2 releasing reaction indicates that diazene binding occurs prior to H2 elimination, and the negative entropy of activation and inverse kinetic isotope effect indicate that H-H bond formation is the rate-limiting step. Thus, substrate binding causes reductive elimination of H2 that formally reduces the metals, and the metals use the additional two electrons to cleave the N-N multiple bond.},
doi = {10.1021/jacs.6b04654},
journal = {Journal of the American Chemical Society},
number = 37,
volume = 138,
place = {United States},
year = {2016},
month = {9}
}