10.1021/jacs.7b04552.s002
Demyan
E. Prokopchuk
Demyan
E.
Prokopchuk
Eric S. Wiedner
Eric S.
Wiedner
Eric D. Walter
Eric D.
Walter
Codrina V. Popescu
Codrina V.
Popescu
Nicholas A. Piro
Nicholas A.
Piro
W. Scott Kassel
W. Scott
Kassel
R. Morris Bullock
R. Morris
Bullock
Michael T. Mock
Michael T.
Mock
Catalytic
N<sub>2</sub> Reduction to Silylamines and
Thermodynamics of N<sub>2</sub> Binding at Square Planar Fe
American Chemical Society
2017
EPR
Fe II complexes
N 2 Binding
tetradentate P 4 N 2 ligand
UV
Fe 0
N 2 binding
Catalytic N 2 Reduction
metal oxidation state
Fe-based N 2 silylation catalyst
N 2 binding affinity
Square Planar Fe
N 2 solubility
2017-06-14 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Catalytic_N_sub_2_sub_Reduction_to_Silylamines_and_Thermodynamics_of_N_sub_2_sub_Binding_at_Square_Planar_Fe/5167381
The geometric constraints imposed
by a tetradentate P<sub>4</sub>N<sub>2</sub> ligand play an essential
role in stabilizing square
planar Fe complexes with changes in metal oxidation state. The square
pyramidal Fe<sup>0</sup>(N<sub>2</sub>)(P<sub>4</sub>N<sub>2</sub>) complex catalyzes the conversion of N<sub>2</sub> to N(SiR<sub>3</sub>)<sub>3</sub> (R = Me, Et) at room temperature, representing
the highest turnover number of any Fe-based N<sub>2</sub> silylation
catalyst to date (up to 65 equiv N(SiMe<sub>3</sub>)<sub>3</sub> per
Fe center). Elevated N<sub>2</sub> pressures (>1 atm) have a dramatic
effect on catalysis, increasing N<sub>2</sub> solubility and the thermodynamic
N<sub>2</sub> binding affinity at Fe<sup>0</sup>(N<sub>2</sub>)(P<sub>4</sub>N<sub>2</sub>). A combination of high-pressure electrochemistry
and variable-temperature UV–vis spectroscopy were used to obtain
thermodynamic measurements of N<sub>2</sub> binding. In addition,
X-ray crystallography, <sup>57</sup>Fe Mössbauer spectroscopy,
and EPR spectroscopy were used to fully characterize these new compounds.
Analysis of Fe<sup>0</sup>, Fe<sup>I</sup>, and Fe<sup>II</sup> complexes
reveals that the free energy of N<sub>2</sub> binding across three
oxidation states spans more than 37 kcal mol<sup>–1</sup>.