Another Torture Track for Quantum Chemistry: Reinvestigation of the Benzaldehyde Amidation by Nitrogen‐Atom Transfer from Platinum(II) and Palladium(II) Metallonitrenes

Israel Journal of Chemistry, Год журнала: 2023, Номер 63(7-8)

Опубликована: Май 24, 2023

Abstract We showcase here a dramatic failure of CCSD(T) theory that originates from the pronounced multi‐reference character key intermediate formed in benzaldehyde amidation by N‐atom transfer Pd(II) and Pt(II) metallonitrenes studied recently combined experimental theoretical work. For detailed analysis we devised minimal model system, for which established reliable reference energies based on approximate full configuration interaction theory, to assess performance single‐reference coupled‐cluster up CCSDTQ(P) excitation level. While RHF‐based suffered errors, one case exceeding 220 kcal mol −1 , show use broken‐symmetry (BS) or Kohn‐Sham (KS) orbital references yields substantially improved results. Further, EOM‐SF‐CCSD(T)(a)* approach met data with excellent accuracy. applied KS‐CCSD(T*)‐F12b variant as high‐level part an ONIOM(KS‐CC:DFT) scheme reinvestigate reactivity metallonitrenes. The revised reaction pathway energetics provide mechanistic rationale observations.

Язык: Английский

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Bonding and Reactivity of d0 Transition Metal Imido Complexes Encoded in their 15N NMR Signatures

Опубликована: Март 4, 2024

Terminal imido complexes, containing metal-nitrogen multiple bonds, have been widely used in organometallic chemistry and homogeneous catalysis. The role of terminal ligands span from reactive site to spectator motif, largely depending on the nature metal center its specific coordination sphere. Aiming at identifying reactivity descriptors for M-N we herein explore solid-state 15N NMR spectroscopy (ssNMR) early-transition complexes augmented by computational studies show that asymmetry parameter k, (skew, 1 ≥ k -1), readily available experiments or calculations, is diagnostic bonds complexes. While inert exhibit skew values (k) close 1, highly moieties display significantly lower (k << 1) as found metallocene bis-imido Natural Chemical Shielding analysis shows away are associated with an asymmetric development pi orbitals around bond moiety, a larger sp2-hybridized character nitrogen. Notably, this descriptor does not directly relate M-N-C angle, illustrating shortcoming evaluating hydridization geometrical parameters alone. Overall, enables obtain direct experimental evidence pi-loading effect seen bis(imido) related thus explaining their reactivity.

Язык: Английский

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Enabling Nucleophilic Reactivity in High-Spin Fe(II) Imido Complexes: From Elementary Steps to Cooperative Catalysis

Accounts of Chemical Research, Год журнала: 2023, Номер 56(23), С. 3392 - 3403

Опубликована: Ноя. 13, 2023

ConspectusTransition metal complexes featuring an M═NR bond have received great attention as critical intermediates in the synthesis of nitrogen-containing compounds. In general, properties imido ligand these are dependent on nature center. Thus, tends to be nucleophilic early transition and electrophilic late complexes. Nonetheless, supporting can a dramatic effect its reactivity. For example, there sporadic examples complexes, often based strongly donating ligands. Building earlier works, this Article, we show that low-coordinate high-spin bis(carbene)borate Fe(II) complex is able access previously unknown reaction pathways, ultimately leading new catalytic transformations. We first focus synthesis, characterization, stoichiometric reactivity highly complex. The entry point for system intermediate-spin three-coordinate Fe(III) complex, which generated from Fe(I) synthon with organic azide. Alkali reduction leads series M+ (M = Li, Na, K) coordinated charge-separated K(18-C-6)) all been isolated fully characterized. Combined electronic structure calculations, results reveal alkali ions moderately polarize Fe═N according K+ ≈ Na+ < Li+. As result, basicity increases charged separated K+, Na+, Li+ validated by intermolecular proton transfer equilibria. impact counterion demonstrated through protonation, alkylation, hydrogen atom abstraction reactions. also directs outcome [2 + 2] reactions benzophenone, where coordination facilitates double metathesis. here, describe how unusual nucleophilicity revealed extended cycloaddition serves basis guanylation carbodiimides under mild conditions. More interestingly, exhibits ene-like alkynes, nitriles, alkenes. These transformations form alkyne nitrile α-deuteration pKa-dictated alkene transposition reactions, respectively. Mechanistic studies role metal-ligand cooperativity facilitating suggest avenues catalysis extend beyond classical nitrene chemistry.

Язык: Английский

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Pd₈(PDip)₆: Cubic, Unsaturated, Zerovalent

Advanced Science, Год журнала: 2024, Номер 11(25)

Опубликована: Апрель 18, 2024

Atomically precise nanoclusters hold promise for supramolecular assembly and (opto)electronic- as well magnetic materials. Herein, this work reports that treating palladium(0) precursors with a triphosphirane affords strongly colored Pd

Язык: Английский

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Cyclic (alkyl)(amino)carbene (CAAC) ligands: Electronic structure and application as chemically- and redox-non-innocent ligands and chromophores

Advances in organometallic chemistry, Год журнала: 2022, Номер unknown, С. 79 - 132

Опубликована: Янв. 1, 2022

Язык: Английский

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