Diverse Behaviors of N₂ on Mo Centers Bearing POCOP-Pincer Ligands and the Role of π-Electron Configuration in Regulating the Pathway of N₂ Activation

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 16, 2025

Activation of N2 through transition-metal complexes has emerged as a powerful strategy for fixation under mild conditions. Dissociative route and associative are considered two major routes transformation on complexes. Homolysis between metal fragments is the crucial step dissociative been proven to be an efficient approach terminal nitride, which key intermediate both routes. Hence, conditions cleavage have attracted much interest discussion. Herein, we investigated reactivity when coordinated Mo centers bearing POCOP-pincer ligands isolated characterized many novel N2-related intermediates such [(POCOPCy)MoI]2(μ-N2) (2Cy), (POCOPCy)Mo(N)(μ-N)MoI (5Cy), {[(POCOPCy)Mo(N2)2]2(μ-N2)}[Na(crypt-222)] (6Cy-crypt), [(POCOPCy)Mo(N2)2(μ-N2)Mo(N)]Na (8Cy). The influences oxidation state centers, π electrons, reaction conditions, etc., N2-reactivity were also studied experimentally theoretically. Accordingly, some fundamental understanding regulation activation pathways was proposed: N2-bridged dimer without ligand trans bridging preferred structure cleavage; having adequate electrons transferred into σ–σ*−σ related orbital in {MoNNMo} manifold key; heating or electron excitation advantageous route.

Язык: Английский

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A three-step strategy for the conversion of pyridines into benzonitriles

Nature Synthesis, Год журнала: 2025, Номер unknown

Опубликована: Март 7, 2025

Язык: Английский

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Monomethylation and -protonation of Lutetium Dinitrogen Complex

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(26), С. 17624 - 17628

Опубликована: Июнь 18, 2024

Due to the highly chemically inert nature, direct activation and transformation of dinitrogen are challenging. Here, we disclose synthesis, isolation, derivatization (N

Язык: Английский

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Spindle-shaped porous cobalt phosphide ultrathin nanosheets as bifunctional electrocatalysts for water splitting

Applied Surface Science, Год журнала: 2025, Номер unknown, С. 162535 - 162535

Опубликована: Янв. 1, 2025

Язык: Английский

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Trendbericht Anorganische Chemie 2024: Nebengruppen‐ und Koordinationschemie

Nachrichten aus der Chemie, Год журнала: 2025, Номер 73(2), С. 56 - 64

Опубликована: Янв. 31, 2025

Abstract Das erste heterobimetallische Dimetallocen; mit sterisch anspruchsvollen Liganden lassen sich einfach‐koordinierte Hauptgruppenverbindungen der Gruppen 13 bis 15 herstellen; neue Diazoverbindungen erlauben es, B‐R‐Einheiten und Kohlenstoffatome zu übertragen.

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Predicting σ⁰π² Carbene-Mediated Hydroboration and Bis-carbene Functionalization of Dinitrogen

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Май 9, 2025

Although the carbene-catalyzed N2 fixation process had been investigated by scientists for decades prior to borylene species, interest in carbene-mediated activation has drawn less attention than that of species past few years, especially unique σ0π2 carbenes. Herein, we demonstrate important role carbenes 1,1-hydroboration and bis-carbene functionalization using density functional theory calculations. Both being kinetically thermodynamically favorable, reaction barriers are as low 13.7 16.6 kcal/mol, respectively. Additionally, such a carbene can also achieve series X-H insertion reactions (X = H, CH3, Bpin, or SiH2Ph), with energies ranging from 8.2 15.3 kcal/mol. Our findings highlight strong potential electronic configuration its versatile transformations, providing valuable insights into main-group-element-mediated chemistry.

Язык: Английский

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Synthesis of an Isostructural Series of Group 6 Complexes Supported by an Alkyne-Based Pincer Ligand

Organometallics, Год журнала: 2025, Номер unknown

Опубликована: Июнь 3, 2025

Язык: Английский

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Predicting Activation of Small Molecules Including Dinitrogen via a Carbene with a σ⁰π² Electronic Configuration

Inorganic Chemistry, Год журнала: 2024, Номер 63(34), С. 15931 - 15940

Опубликована: Авг. 9, 2024

Although the main group species in s and p blocks have begun to gain prominence field of dinitrogen (N2) activation recent years, reports carbene-mediated N2 remain particularly rare, especially for carbenes with a σ0π2 electronic configuration. Herein, we demonstrate examples initiated by carbene configuration consequent hydroboration reaction (with barrier as low 19.9 kcal/mol) via density functional theory calculations. Meanwhile, "push–pull" effect upon introduction hydroborenium complex facilitates generation thermodynamically kinetically more stable product. In addition, such can also activate series H–X (X = H, CH3, or Bpin) bonds through an oxidative addition process energies ranging from 6.0 18.0 kcal/mol. Our findings highlight importance small molecule activation, activation.

Язык: Английский

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Denitrogenative Ring-Contraction of Pyridines to a Cyclopentadienyl Skeleton at a Dititanium Hydride Framework

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(45), С. 31348 - 31355

Опубликована: Окт. 31, 2024

Selective removal of the nitrogen atom from an aromatic N-heterocycle, such as pyridine, is significant interest and importance, yet it remains highly challenging. Here, we report unprecedented denitrogenative ring-contraction reaction pyridines at a dititanium hydride framework, yielding cyclopentadienyl nitride species under mild conditions. The pyridine with tetrahydride complex (1) bearing rigid acridane-based PNP-pincer ligands room temperature produced cyclopentadienyl/nitride (2), in which two Ti atoms are bridged by one bonded to group formed denitrogenation ring-contraction. reactions 2-, 3-, 4-methylpyridines 1 similar conditions yielded same product (3), methylcyclopentadienyl-ligated analog 2. When 2,4- or 3,5-dimethylpyridine reacted 60 °C, 1,3-dimethylcyclopentadienyl-ligated (5) almost quantitatively. mechanistic details have been elucidated isolation key intermediates density functional theory calculations. It was revealed that proceeded via coordination N unit followed H2 release, C═N reduction, C–N bond cleavage (ring-opening denitrogenation), C–C coupling (ring closing). involvement C–H activation isopropyl PNP ligand later stages significantly contributed stabilization product. This work not only provides insights into N-heterocycles but also represents novel example skeletal editing N-heterocycles.

Язык: Английский

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Origin of Reactivity Trends of an Elusive Metathesis Intermediate from NMR Chemical Shift Analysis of Surrogate Analogs

Опубликована: Апрель 15, 2024

Olefin metathesis has been established as an efficient tool to build carbon-carbon bonds, and its widespread applications in organic synthesis have made possible by the development of homogeneous catalysts – Grubbs Schrock-type that operate through same intermediates Chauvin mechanism. With d0 catalysts, first elementary step, olefin-coordination, is often rate determining, but it rarely explored due lack accessible relevant molecular analogs. Here, we develop a surrogate this key olefin-coordination intermediate, namely cationic tungsten oxo-methylidene complex bearing two N-heterocyclic carbene ligands, [WO(CH2)Cl(IMes)2](OTf) (1) (IMes = 1,3-dimesitylimidazole-2-ylidene; OTf triflate counter-anion) resulting trigonal bipyramidal (TBP) geometry, along with neutral octahedral analog [WO(CH2)Cl2(IMes)2] (2), isostructural oxo-methylidyne derivative [WO(CH)Cl(IMes)2] (3). These compounds were fully characterized state-of-the-art methods, including single-crystal X-ray diffraction (scXRD) multinuclear (1H, 13C, 183W) solution NMR spectroscopy. The analysis their solid-state 13C 183W MAS signatures, computed 17O parameters, helps correlate electronic structures patterns evidences importance competition between three equatorial ligands TBP complexes. Further validates suitability 1 molecule interrogate structure olefin coordination intermediate cycle. Anchored on experimentally obtained parameters for 1, computational series highlights interplay σ- π-donating modulating stability intermediates, paralleling reactivity. In work, spectroscopy descriptors reveal origin advantage dissymmetry σ-donating abilities ancillary catalysts: weak σ-donors avoid orbital-competition oxo ligand upon formation while stronger compromise M≡O triple bonding thus render step energy expensive.

Язык: Английский

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