New high-spin pathways: All four feasible reaction pathways for alkane hydroxylation by nonheme iron(IV)–oxo complexes have been investigated computational methods. The triplet σ path is too high in energy to be involved CH bond activation, but the reactivity of quintet π channel competes with and may thus offer a new approach specific control activation species (see scheme).

This perspective discusses the principles of multistate scenario often encountered in transition metal catalyzed reactions, and is organized as follows. First, several important theoretical concepts (physical versus formal oxidation states, orbital interactions, use (spin) natural corresponding orbitals, exchange enhanced reactivity connection between valence bond molecular based electronic structure analysis) are presented. These then used to analyze changes occurring reaction C–H by...

A mechanistically unique, simultaneous activation of two C–H bonds methane has been identified during the course its reaction with cationic copper carbide, [Cu–C]+. Detailed high-level quantum chemical calculations support experimental findings obtained in highly diluted gas phase using FT-ICR mass spectrometry. The behavior [Cu–C]+/CH4 contrasts that [Au–C]+/CH4, for which a stepwise bond-activation scenario prevails. An explanation distinct mechanistic differences coinage metal complexes...

Significance A combined experimental/computational approach provides deep mechanistic insight into an unprecedented cluster-mediated N−H coupling mimicking the industrially extremely important ammonia synthesis from N 2 and H (the “Haber–Bosch” process) at room temperature. Crucial steps were identified for both forward reactions (i.e., activation of ) backward process Ta + -mediated decomposition NH 3 ). The central intermediate either path corresponds to , a four-membered ring with...

An unprecedented, spontaneous, and complete cleavage of the triple bond N2 in thermal reaction 15N2 with Ta214N+ was observed experimentally by Fourier transform ion cyclotron resonance mass spectrometry; mechanistic aspects degenerate ligand exchange were addressed high-level quantum chemical calculations. The "hidden" dis- reassembly N2, mediated Ta2N+, constitutes a full catalytic cycle. A frontier orbital analysis reveals that scission is essentially governed donation d-electrons from 2...

In this work, the reactions of C–H bond activation by two series iron-oxo (1 (FeIV), 2 (FeV), 3 (FeVI)) and -nitrido model complexes (4 5 6 with a nearly identical coordination geometry but varying iron oxidation states ranging from IV to VI were comprehensively investigated using density functional theory. We found that in distorted octahedral environment, species their isoelectronic nitrido analogues feature totally different intrinsic reactivities toward cleavage. case complexes, reaction...

Mechanistic aspects of the C-H bond activation methane by metal-carbide cations MC+ 3d transition-metals Sc-Zn were elucidated NEVPT2//CASSCF quantum-chemical calculations and verified experimentally for M = Ti, V, Fe, Cu using Fourier transform ion-cyclotron resonance mass spectrometry. While species with Sc, Cr, Cu, Zn activate CH4 at ambient temperature, this is prevented carbide Mn, Co high apparent barriers; NiC+ has a small barrier. Hydrogen-atom transfers from to found proceed via...

Uranium (U), a high-performing, low-emission energy source, is driving sustainable economic growth. Herein, we synthesized two crystalline phases (HPOC-α and β) by an unreported amidoxime organic cage used for uranium capture. The revealed crystal structures adsorption test showed that accessible functional groups were essential to uranyl ions sorption. presented in HPOC-α gifted it equilibrium capacity of 1682 mg g–1 could mostly maintain the performance after adsorption–desorption cycles....

In recent years, the development and application of semiconductor materials with excellent photocatalytic properties have been paid wide attention in addressing issue water pollution. Hollow nanospheres titanium dioxide (TiO2), doped Fe ions, fabricated through hard template method for degradation organic pollutants. The hierarchical were synthesized using hydrothermal carbon spheres as a template, resulting an average diameter about 200 nm, mesoporous structure characterized by remarkably...

Neue High-Spin-Pfade: Die vier plausiblen Reaktionspfade der Alkanhydroxylierung durch Nichthäm-Eisen(IV)-Oxo-Komplexe wurden rechnerisch untersucht. Der Triplett-σ-Pfad ist energetisch zu hoch, um an einer C-H-Aktivierung beteiligt sein – jedoch konkurriert die Reaktivität des Quintett-π-Kanals mit dem Triplett-Pfad, was einen neuen Ansatz für spezifische Eisen(IV)-Oxo-Spezies bieten könnte (siehe Schema). Detailed facts of importance to specialist readers are published as ”Supporting...

Complexes 1–OH and 1–F are related complexes that share similar [X–FeIII–O–FeIV═O]3+ core structures with a total spin S of 1/2, which arises from antiferromagnetic coupling an = 5/2 FeIII–X site 2 FeIV═O site. EXAFS analysis shows has nearly linear FeIII–O–FeIV compared to 1–OH, Fe–O–Fe angle ∼130° due the presence hydrogen bond between hydroxo oxo groups. Both at least 1000-fold more reactive C–H cleavage than 2, complex [OH–FeIV–O–FeIV═O]4+ having individual 1 FeIV units. Interestingly,...

In this article, we present density functional theory (DFT) calculations on the iron(IV)-oxo catalyzed methane C-H activation reactions for complexes in which Fe(IV)═O core is surrounded by five negatively charged ligands. We found that it follows a hybrid pathway mixes features of classical σ- and π-pathways quintet surfaces. These show Fe-O-H arrangement bent sharp contrast to collinear character as observed σ-pathways before. The have also shown equatorial ligands play key roles tuning...

We present a high-level computational study on methanol C-H and O-H bond cleavages by bare [Fe(IV)O](2+), as well benchmarks of various density functional theory (DFT) methods. considered direct concerted hydrogen transfer (DHT CHT) pathways, respectively. The potential energy surfaces were constructed at the CCSD(T)/def2-TZVPP//B3LYP/def2-TZVP level theory. Mechanistically, (1) cleavage is dominant activation only plays minor role PESs; (2) DHT from methyl should be most practical channel;...

In the course of combined computational and mass spectrometry-based mechanistic studies, recently we came across rather unusual, if not unprecedented, effects transition-metal ions ligands when simple metal oxides or carbides are subjected to thermal gas-phase reactions with methane. Interestingly, "Gedankenexperiments" demonstrate how these can be modeled using oriented external electric fields (OEEFs), thus expanding their predicted role as "smart reagents" (Shaik et al., Nat. Chem., 2016,...

Abstract The reactivity of the cationic metal‐carbon cluster FeC 4 + towards methane has been studied experimentally using Fourier‐transform ion cyclotron resonance mass spectrometry and computationally by high‐level quantum chemical calculations. At room temperature, H is formed as main ionic product, experimental findings are substantiated labeling experiments. According to extensive calculations, C−H bond activation step proceeds through a radical‐based hydrogen‐atom transfer (HAT)...

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Mechanistic insight into the thermal O–H bond activation of water by cubane-like, prototypical heteronuclear oxide cluster [Al2Mg2O5]•+ has been derived from a combined experimental/computational study. Experiments in highly diluted gas phase using Fourier transform ion-cyclotron resonance mass spectrometry show that hydrogen-atom abstraction cation occurs at ambient conditions accompanied liberation an OH• radical. Because complete randomization all oxygen atoms prior to fragmentation,...

The possible reaction mechanism of atomic radical F with propene is investigated theoretically by a detailed potential energy surface (PES) calculation at the UMP2/6-311++G(d,p) and CCSD(T)/cc-pVTZ (single-point) levels using ab initio quantum chemistry methods transition-state theory. Various paths including addition-isomerization-elimination reactions direct H-atom abstraction are considered. Among them, most feasible pathway should be ((2)F) attacking on C [Formula: see text] double bond...

The complete reaction mechanism of the platinum-mediated arene [(N−N)PtPh2 (N−N = diimine ArNCMe−CMeNAr with Ar 2,6-Me2C6H3)] C−H activation has been investigated by using B3LYP density functional theory method. calculations show that protonation should occur at metal center, giving a coordinately unsaturated five-coordinate Pt(IV) hydride which is trapped acetonitrile; otherwise monophenyl solvento cations (N−N)Pt(Ph)(NCMe)+ be isolated and characterized spectroscopically. Of H exchange...

Presented here is that isolated, long-lived electronic states of ReC+ serve as the root cause for distinctly different reactivities this diatomic ion in thermal activation dihydrogen. Detailed high-level quantum chemical calculations support experimental findings obtained highly diluted gas phase using FT-ICR mass spectrometry. The origin existence these excited and resulting implications varying mechanisms dihydrogen splitting are addressed.

Lanthanide ions are extensively utilized in optoelectronic materials, owing to their narrow emission bandwidth, prolonged lifetime, and elevated fluorescence quantum yield. Inorganic non-metallic materials commonly serve as host matrices for lanthanide complexes, posing noteworthy challenges regarding loading quantity performance stability post-loading. In this investigation, an enhanced Stöber method was employed synthesize mesoporous hollow silica, diverse forms of SiO2@Eu(TTA)3phen (S@Eu)...

Abstract Recoverin is an important neuronal calcium sensor (NCS) protein, which have been implicated in a wide range of Ca 2+ signaling events neurons and photoreceptors. To characterize the conformational transition recoverin from myristoyl sequestered state to extrusion state, series conventional molecular dynamics (CMD) targeted (TMD) simulations were performed. The 36.8 ns long CMD TMD on revealed reliably pathway, can be viewed as sequential two‐stage process. A very mechanistic...