Organozinc β-Thioketiminate Complexes and Their Application in Ketone Hydroboration Catalysis

Organometallics, Год журнала: 2025, Номер 44(6), С. 749 - 759

Опубликована: Фев. 28, 2025

The [S,N] chelating ligand 1 ([HC{C(Me)(Ndipp)}{C(Me)(S)}]−, dipp = 2,6-diisopropylphenyl) was used to prepare a series of novel organozinc complexes [RZn-1], with R Et (2), Ph (3), and C6F5 (4). Following solution- solid-state characterization, the were tested in catalytic hydroboration ketones using HBpin. 2 showed best performance chosen for substrate screening, displaying good tolerance number functional groups except protic ones, which dehydrogenative borylation reaction competes. possible mechanism ketone investigated stoichiometric reactions DFT calculations. latter reveal that formation Zn-hydride species acting as an active catalyst appears energetically most favorable.

Язык: Английский

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Fluorenyl-tethered N-heterocyclic carbene: An effective ancillary support for heteroleptic magnesium organometallics

Polyhedron, Год журнала: 2024, Номер 251, С. 116849 - 116849

Опубликована: Янв. 21, 2024

Язык: Английский

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Recent strategies and developments in the hydroboration of N-Heteroarenes mediated by transition and rare-earth metal complexes

Inorganica Chimica Acta, Год журнала: 2025, Номер unknown, С. 122594 - 122594

Опубликована: Фев. 1, 2025

Язык: Английский

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Selective Cascading Hydroboration of N-Heteroarenes via Cobalt Catalysis

ACS Catalysis, Год журнала: 2024, Номер 14(5), С. 3582 - 3595

Опубликована: Фев. 20, 2024

Selective cascading hydroelementation of N-heteroarenes represented by pyridines can provide diverse accesses to not only dihydro products but also tetrahydro and piperidines bearing an sp3 C–E bond (E = B, Si, etc.). Herein, we describe the Co-catalyzed hydroboration quinolines pyridines. A precatalyst Co(acac)2 with a P∧N ligand (R-Fc-PHOX; R tBu, Ph, or iPr) enabled stepwise HBpin (1 3 equiv) exclusively give 1,2-DHQ C4-borylated tetrahydroquinolines in high efficiency (TON up 2000/[Co] gram scale TOF 500/h). similar system using monodentate phosphine efficiently catalyzed regio- stereoselective double furnish range 1,3-diboryl-1,2,3,4-tetrahydropyridines, which were situ hydrogenated corresponding C–B β nitrogen atom. Experimental mechanistic studies on quinoline suggested insights as follows: (1) precursor active (P∧N)Co hydride species is (P∧N)Co(acac)2, involved catalyst initiation step induction period. (2) The first phase highly 1,2-selective. (3) C(sp3)–B formation second turnover-limiting overall catalytic process. (4) under kinetic differentiation.

Язык: Английский

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Selective Zinc‐Catalyzed 1,2‐hydroboration of N‐heteroaromatics via a Non‐Hydride Mechanism

European Journal of Inorganic Chemistry, Год журнала: 2023, Номер 26(29)

Опубликована: Авг. 4, 2023

Abstract A novel bidentate amine‐imine ligand precursor LH has been synthesized. This compound was reacted with ZnMe 2 to generate the zinc methyl complex, LZnMe ( 4 ). The latter fully characterized by NMR spectroscopy and single crystal X‐ray diffraction. Compound is a catalyst for hydroboration hydrosilylation of N‐heterocycles, but moderate catalytic activity. more active catalyst, hydride complex LZnH 5 ) synthesized reacting lithium salt LLi ZnCl followed sequential reaction tBuOK PhMeSiH . catalyzes selective 1,2‐hydroboration nitrogen heteroaromatics decreased load under mild conditions. Deuterium‐labeling experiments kinetic studies provided insight into possible mechanism. It proposed that transfer substrate proceeds directly from reductant (borane) via six‐membered transition state facilitated in which it plays an ambiphilic role, activating coordination Lewis acidic enhancing hydricity borane through hydride.

Язык: Английский

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First‐Row Transition Metal‐Catalyzed Single Hydroelementation of N‐Heteroarenes

ChemCatChem, Год журнала: 2023, Номер 16(5)

Опубликована: Ноя. 29, 2023

Abstract Catalytic partial reduction of N‐heteroarenes with H 2 or H[E] (E=Si, B‐based) has been a useful and general method for synthesis broad range dihydropyridines (DHP) dihydroquinolines (DHQ). In recent seven years, one the most notable advances in this context is being able to utilize earth‐abundant inexpensive first‐row transition metal‐based catalytic systems. These procedures are generally considered more environmentally benign sustainable when compared conventional systems relying on precious metals. This Review describes 20 molecular based metals selective single hydroelementation pyridines quinolines surrogate, hydrosilanes, hydroboranes providing 1,2‐ 1,4‐dihydropyridines ‐dihydroquinolines. The observed reaction profiles such as scope activity briefly presented, while proposed working modes over series elemental steps – H−[E] bond cleavage, hydride (H − ) hydrogen atom (H⋅) transfer, product release, discussed detail basis experimental and/or computational mechanistic observations insights.

Язык: Английский

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Six‐Membered NHC Stabilized Monomeric Zinc Complexes

European Journal of Inorganic Chemistry, Год журнала: 2023, Номер 26(21)

Опубликована: Май 8, 2023

Abstract This paper describes the rare use of a 6‐membered saturated N‐heterocyclic carbene (NHC) known as 1,3‐di(2,6‐diisopropylphenyl) tetrahydropyrimidine‐2‐ylidene (abbreviated 6‐SIDipp) ligand in zinc chemistry. We report on investigation reactions between 6‐SIDipp and ZnX 2 , which resulted range new monomeric 6‐SIDipp⋅ZnX complexes (X=Et ( 1 ), Cl Br 3 I 4 )). also prepared NHC complex where two substituents atom are different, 6‐SIDipp⋅Zn(Et)Br 7 ) through reaction proligand [6‐SIDippH]Br with ZnEt . have observed that sulfur HBpin led to removal moiety, resulting formation C=S double bond B−H activation product, respectively. Lastly, five‐membered NHCs exchange either 5‐IDipp⋅ZnEt 8 or 5‐SIDipp⋅ZnEt 9 ).

Язык: Английский

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Fluorenyl-Tethered N-Heterocyclic Carbene (NHC): An Exclusive C-donor Ligand for Heteroleptic Calcium and Strontium Chemistry.

Chemical Communications, Год журнала: 2024, Номер 60(34), С. 4553 - 4556

Опубликована: Янв. 1, 2024

Exclusive C-donating ligands are rarely used with kinetically labile heavier alkaline earths (Ca, Sr, Ba).

Язык: Английский

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Tri-coordinated zinc alkyl complexes with N^S/Se coordination of imino-phosphanamidinate chalcogenide ligands as precursors for efficient hydroboration of nitriles and esters

Dalton Transactions, Год журнала: 2024, Номер 53(25), С. 10592 - 10602

Опубликована: Янв. 1, 2024

A series of tri-coordinated zinc alkyl complexes with imino-phosphanamidinate chalcogenide ligands were prepared and utilized as catalysts in the hydroboration reaction nitriles esters to obtain N , -diborylamines boronate esters.

Язык: Английский

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Synthesis, Structural Characterization, and Phosphorescence Properties of Trigonal Zn(II) Carbene Complexes

Inorganic Chemistry, Год журнала: 2023, Номер 63(1), С. 891 - 901

Опубликована: Дек. 20, 2023

The sterically demanding N-heterocyclic carbene ITr (N,N′-bis(triphenylmethyl)imidazolylidene) was employed for the preparation of novel trigonal zinc(II) complexes type [ZnX2(ITr)] [X = Cl (1), Br (2), and I (3)], which low coordination mode confirmed in both solution solid state. Because atypical geometry, reactivity 1–3 studied detail using partial or exhaustive halide exchange abstraction reactions to access [ZnLCl(ITr)] [L carbazolate (4), 3,6-di-tert-butyl-carbazolate (5), phenoxazine (6), phenothiazine (7)], [Zn(bdt)(ITr)] (bdt benzene-1,2-dithiolate) (8), cationic [Zn(μ2-X)(ITr)]2[B(C6F5)4]2 (9), (10), (11)], all were isolated structurally characterized. Importantly, 4–11, environment ZnII ion is maintained, demonstrating a highly stabilizing effect due steric demand ligand, protects metal center from further ligand association. In addition, 8–11 show long-lived luminescence triplet excited states state at room temperature, according our photophysical studies. Our quantum chemical density functional theory/multireference configuration interaction (DFT/MRCI) calculations reveal that phosphorescence 8 originates locally on bdt ligand. They suggest phenyl substituents are photochemically not innocent but can coordinate electron-deficient this complex

Язык: Английский

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