Cooperativity between low-valent iron and potassium promoters in dinitrogen fixation.
A density functional theory (DFT) study was performed to understand the role of cooperativity between iron-β-diketiminate fragments and potassium promoters in N(2) activation. Sequential addition of iron fragments to N(2) reveals that a minimum of three Fe centers interact with N(2) in order to break the triple bond. The potassium promoter stabilizes the N(3-) ligand formed upon N(2) scission, thus making the activated iron nitride complex more energetically accessible. Reduction of the complex and stabilization of N(3-) by K(+) have similar impact on the energetics in the gas phase. However, upon inclusion of continuum THF solvent effects, coordination of K(+) has a reduced influence upon the overall energetics of dinitrogen fixation; thus, reduction of the trimetallic Fe complex becomes more impactful than coordination of K(+) vis-à-vis N(2) activation upon the inclusion of solvent effects.
Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, Texas 76203-5017, USA.
Travis M
TM
Figg
Patrick L
PL
Holland
Thomas R
TR
Cundari
D007501:Iron / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009586:Nitrogen Fixation; D011188:Potassium / Q000737:chemistry*; D011789:Quantum Theory
D008024:Ligands; D007501:Iron; D011188:Potassium