Hydrogen Atom Abstraction from an Os(NH) Complex Generates an Os(NH) Complex: Experimental and Computational Analysis of the N-H Bond Dissociation Free Energies and Reactivity.

Double hydrogen atom abstraction from (TMP)Os(NH) (TMP = tetramesitylporphyrin) with phenoxyl or nitroxyl radicals leads to (TMP)Os(NH). This unusual bis(amide) complex is diamagnetic and displays an N-H resonance at 12.0 ppm in its H NMR spectrum.

Weakening the N-H Bonds of NH Ligands: Triple Hydrogen-Atom Abstraction to Form a Chromium(V) Nitride.

Weakening and cleaving N-H bonds is crucial for improving molecular ammonia (NH) oxidation catalysts. We report the synthesis and H-atom-abstraction reaction of bis(ammonia)chromium porphyrin complexes Cr(TPP)(NH) and Cr(TMP)(NH) (TPP = 5,10,15,20-tetraphenyl--porphyrin and TMP = 5,10,15,20-tetramesityl--porphyrin) using bulky aryloxyl radicals. The triple H-atom-abstraction reaction results in the formation of Cr(por)(≡N), with the nitride derived from NH, as indicated by UV-vis and IR and single-crystal structural determination of Cr(TPP)(≡N).

Exploring the Tunability of Trimetallic MOF Nodes for Partial Oxidation of Methane to Methanol.

Density functional theory is used to study the tunability of trigonal prismatic SBUs found in metal-organic frameworks (MOFs) such as MIL-100, MIL-101, and PCN-250/MIL-127 of chemical composition MM(μ-O)(RCOO) for the partial oxidation of methane to methanol. We performed a combinatorial screening by varying the composition of the trimetallic node (M)(M) (where M and M = V, Cr, Mn, Fe, Co, and Ni) and calculated the reaction pathway on both M and M sites. The systematic replacement of metals in the trimetallic cluster allowed us to study the influence of spectator atoms on the catalytic activity of a specific metal site in the cluster toward the NO activation and C-H bond activation steps of the reaction.

DFT Study on the Catalytic Activity of ALD-Grown Diiron Oxide Nanoclusters for Partial Oxidation of Methane to Methanol.

Using density functional theory (DFT), we studied the catalytic activity of iron oxide nanoclusters that mimic the structure of the active site in the soluble form of methane monooxygenase (sMMO) for the partial oxidation of methane to methanol. Using NO as the oxidant, we consider a radical-rebound mechanism and a concerted mechanism for the oxidation of methane on either a bridging oxygen (O) or a terminal oxygen (O) active site. We find that the radical-rebound pathway is preferred over the concerted pathway by 40-50 kJ/mol, but the desorption of methanol and the regeneration of the oxygen site are found to be the highest barriers for the direct conversion of methane to methanol with these catalysts.