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. 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) complex reacts with azobenzene (PhN═NPh) to perform a four-electron reduction, 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.
Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
Sarina M
SM
Bellows
Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
Nicholas A
NA
Arnet
Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
Prabhuodeyara M
PM
Gurubasavaraj
Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
William W
WW
Brennessel
Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
Eckhard
E
Bill
Department of Chemistry and CASCaM, University of North Texas , Denton, Texas 76203, United States.
Thomas R
TR
Cundari
Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.|Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
Patrick L
PL
Holland
D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D005296:Ferrous Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*
D001391:Azo Compounds; D005296:Ferrous Compounds; C009850:azobenzene; D009584:Nitrogen