A Serendipitous Rendezvous with a Four‐Center Two‐Electron Bonded Intermediate in the Aerial Oxidation of Hydrazine

Abstract

Oxidation by dioxygen has a rich repertoire of mechanistic intricacies. Herein, we report a hitherto unknown paradigm of dioxygen activation reaction which propagates through a four center two electron (4c-2e) bound species. Using static DFT and ab initio quantum chemical techniques we have unraveled the oxidation pathway for hydrazine and its methylated analogues by dioxygen which involves formation of this unconventional 4c-2e bonded species en route to the oxidation products. Inconvertible evidence in favor of such an unprecedented dioxygen activation route is provided by capturing the events of formation of the 4c-2e species in aqueous phase for hydrazine and its congeners and the experimentally observed products from the respective 4c-2e species, like H2O2 and N2H2 , diazene in the case of hydrazine using Car-Parrinello molecular dynamics simulations.

Cleavage of Organosolv Lignin to Phenols Using Nitrogen Monoxide and Hydrazine

“…The assumption that the aldehydes 23a and 23b are direct precursors of the 4-methylphenols 17b and 17d was confirmed by reacting both aldehydes with hydrazine under the optimized reductive conditions to give 17b and 17d in yields of 57 and 41%, respectively. In agreement with this is also the observation that when the reduction step is carried out under "open" instead of "closed" conditions so that the reductant hydrazine is likely to be consumed faster to nitrogen due to its facilitated access to oxygen, 30 the yield of phenol 17b, and in most cases also that of 17d, decreases (Figure 4). The fact that phenols 17a and 17c were not obtained in the hydrazine-mediated reductions of 23a and 23b necessitates their formation from the oxidized organosolv lignin 22.…”

Understanding the Unexpected Product Distribution in the Aerial Oxidation of Carbene‐Stabilized Diphosphorus Complex

“…This origin of the high magnitude of the z component in similar molecular systems has been previously discussed in detail by Prabhakar et al . and Banerjee et al …”

“…2018,24,[4350][4351][4352][4353][4354][4355][4356][4357][4358][4359][4360] www.chemeurj.org detailede lectronic picture at the MECP). This origin of the high magnitude of the z component in similarm olecular systems has been previously discussed in detail by Prabhakar et al [13] and Banerjee et al [26] The oxygenation of NHC-stabilized P 2 is initiated by the endon h 1 -approach of dioxygen (O 2a ÀO 2b ). Dioxygenc oordinates with one phosphorus atom (P a )t of orm ac losed-shells uperoxide (O 2 2À )c omplex( INT 1), which is stabilized by 10.2 kcal mol À1 with respecttot he reactant (1)and gaseous 3 O 2 .INT 1isr epresentativeo fh 1 -coordination of O 1a ÀO 1b to the P 2 species with one of the phosphorus atoms (P a ;s ee Figure 1).…”

Calculations of magnetically induced current densities: theory and applications

“…116 When the current densities are calculated at multiconfiguration levels of theory, current density analyses ( 7) can also yield information about bond forming and bond breaking as well as about the stability of transition states (Pathak S, Bast R, Ruud K, private communication). 124 Very recent calculations of the current density for a hypothetical concerted reaction pathway from isolated acetylene molecules to benzene and cyclooctatetraene showed that the formation of the ring current can be monitored by performing current density calculations at the DFT level. 125 A schematic overview of possible information that is accessible through current density analyses is given in Figure 13 chemists.…”