Computational Study Illustrating NCN-Palladium(IV) Involvement in Generating Pd0 Species to Facilitate Pd0/PdII Heck-Type Catalysis with Diphenyliodine(III) Species DOI
Allan J. Canty, Alireza Ariafard

Organometallics, Journal Year: 2023, Volume and Issue: 42(22), P. 3227 - 3235

Published: Nov. 8, 2023

Density functional theory has been applied in a mechanistic study of the role pincer complex PdII(NCN–N,C,N)(O2CPh-O) ([NCN]- = [2,6-(Me2NCH2)2C6H3]−) (3) Heck-type catalysis presence diphenyliodine(III) triflate as oxidative arylating agent for CH2═CHAr and bicarbonate base to afford PhCH═CHAr (Ar p-BrC6H4). The initially formed palladium(IV) PhPd(NCN–N,C,N)(OBz···HOCO2–O,O) (9) (ΔG‡ 31.6 kcal/mol) undergoes Ph···Cipso reductive elimination form PdII{NC(Ph)N–N,C,N}(OBz···HOCO2–O,O) (11) 25.6 kcal/mol), which is reduced by palladium(0) species. Reduction Pd0 occurs via deprotonation one NMe2 group provide "–CH2–N(Me)–CH2–PdII″ moiety 23.6 followed nucleophilic attack on this give product with "–CH2–NMe(CH2OCO2H)″ 14.5 kcal/mol). exceptionally facile addition Ph2I(HCO3) 5.1 Modeling [Pd(benzene)(O2CPh)]− provides similar result 5.6 allowing entry PhPdII species be able undergo migratory insertion CH2═CAr 14.4 β-hydride 16.2 processes Pd0/PdII catalysis. Activation barriers reduction PdIV Pd0, process, are lower than initial oxidation species, ensuring that only small quantity PdII(NCN)(OBz) consumed, accord its completion Computational studies PdIV-mediated revealed energetically unfavorable preference formation CH2═C(Ar)Ph rather experimentally reported PhCH═CHAr. This reveals precatalyst, PdII elimination, reducing extremely diaryliodine(III) reagent selectivity differences centers.

Language: Английский

Site-Selectivity of C(sp2)–H Oxidative Addition of Fluorinated Arenes with Pyridine(dicarbene) Cobalt(I) Complexes and Aryl Isomerization DOI
Haozheng Li, Hanna H. Cramer, Jose B. Roque

et al.

Organometallics, Journal Year: 2025, Volume and Issue: unknown

Published: March 26, 2025

The rate, site-selectivity, and product isomerization of the C(sp2)–H oxidative addition arenes with pyridine(dicarbene) cobalt methyl phenyl complexes have been investigated four representative varying electronic steric properties. rates activation to yield cobalt-aryl products subsequent aryl were influenced by properties arene; relatively electron-poor arene 3-fluorobenzotrifluoride underwent more than 70 times faster electron-rich substrate, 3-fluoro-N,N,α-trimethylbenzeneacetamide. In all cases, meta-to-fluorine was major at low conversion, which subsequently isomerized ortho isomer over time. Deuterium-labeling experiments measurement methane isotopologues establish that early conversion arises from kinetically preferred, meta-selective addition. Density functional theory calculations support pathways involving cobalt(I)–(III) redox cycles cobalt(I) occurring a high barrier followed reductive elimination. Despite strong σ-donating pincer ligand, π-accepting character carbene donors lowers for elimination, hence, cobalt(III) intermediates not observed.

Language: Английский

Citations

1
Synthesis and Characterization of Heptacoordinated Molybdenum(II) Complexes Supported with 2,6-Bis(pyrazol-3-yl)pyridine (bpp) Ligands DOI Creative Commons

Arno Estival,

Luis Blancarte-Carrazco, L.M.C. Pinto

et al.

Dalton Transactions, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Coordination of the redox non-innocent and proto-responsive 2,6-bis(pyrazol-3-yl)pyridine (bpp) ligand to Mo(0) precursors in presence silver acetate produces hepta-coordinated Mo( ii ) complexes moderate good yields.

Language: Английский

Citations

0
Utilization of ruthenium(0) for σ-bond activation: Formation of organoruthenium complexes and emergence of their catalytic activity via in situ Ru-C bond cleavage DOI
M. Das, Aparajita Mukherjee,

Anannya Saha

et al.

Journal of Organometallic Chemistry, Journal Year: 2025, Volume and Issue: unknown, P. 123567 - 123567

Published: Feb. 1, 2025

Language: Английский

Citations

0
Rhodium(III)-Catalyzed C–C Bond Formation by Direct C–H Activation DOI
Haiqing Luo, Xiaolan Li

Synlett, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 18, 2025

Abstract Transition-metal-catalyzed functionalizations of C–H bonds to construct C–C represent an ideal route in the synthesis valuable organic molecules. In particular, rhodium(III)-catalyzed bond activation offers attractive strategy due its efficiency and step economy for direct functionalization synthesis. Consequently, recent developments this area have assured a high level regioselectivity reactions. Account, we summarized our achievements sp2- sp3-C–H using rhodium catalyst. The scope, limitation, mechanism these reactions been described briefly. 1 Introduction 2 Arylation 2.1 Aromatic C(sp2)–H 2.2 Benzylic C(sp3)–H 2.3 Olefinic 3 Alkenylation Alkylation 4 Heteroarylation 5 Conclusion

Language: Английский

Citations

0
Synthesis of pincer rare-earth metal chlorides bearing indol-2-yl motifs with nonsymmetrical hard and soft appendant side arms and their catalytic applications DOI
Yao Tong,

Chenghao Chu,

Tianhao Li

et al.

Journal of Molecular Structure, Journal Year: 2025, Volume and Issue: unknown, P. 142404 - 142404

Published: April 1, 2025

Language: Английский

Citations

0
Stable Pincer Gold(III)‐TADF Emitters with Extended Donor–Acceptor Separation for Efficient Vacuum‐Deposited OLEDs with Operational Lifetime (LT95) up to 3831 h at 1000 cd m−2 DOI Creative Commons

Hui‐Xing Shu,

Shuo Xu, Wai‐Pong To

et al.

Advanced Science, Journal Year: 2025, Volume and Issue: unknown

Published: April 26, 2025

Abstract Although gold‐TADF (thermally activated delayed fluorescence) emitters have attractive prospects as next‐generation practical OLED emitters, the performance of OLEDs utilizing gold(I)‐ and gold(III)‐TADF lags behind requirements applications, device lifetime has become a bottleneck. Here, novel pincer that are easily fabricated with tunable donor acceptor ligands presented. These exhibit an extended molecular π‐distance along transition dipole moment, resulting in significant reduction electron exchange energy between S 1 T excited states, thus narrowing singlet–triplet gap (Δ E ST ). The combination small Δ heavy‐atom (Au, S) effect greatly enhances spin‐flip dynamics produces efficient TADF (photoluminescence quantum yields up to 90%) high radiative decay rate constants ( k r 10 6 s −1 ), short lifetimes τ less than 1.2 µs) thin films at room temperature. Vacuum‐deposited based on these demonstrate impressive stability, achieving i) maximum external efficiency (EQE max ) 22.2%, ii) record‐ long operational (LT 95 3831 h initial luminance 1000 cd m −2 . This excellent durability makes emitter promising competitive alternative iridium platinum for applications.

Language: Английский

Citations

0
Unsymmetrical NNE (E = S, Se) Pincer Palladium(II) Complexes: Syntheses, Structure, and Catalytic Activity in Decarboxylative Heteroarylation of Coumarin-3-carboxylic Acids DOI

Prakash N. Swami,

Neha Meena,

Hemant Joshi

et al.

Organometallics, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Language: Английский

Citations

0
Mono and Dinuclear Palladium Pincer Complexes of NNSe Ligand as a Catalyst for Decarboxylative Direct C−H Heteroarylation of (Hetero)arenes DOI Open Access
Sohan Singh,

Vikki N. Shinde,

Sunil Kumar

et al.

Chemistry - An Asian Journal, Journal Year: 2023, Volume and Issue: 18(19)

Published: Aug. 21, 2023

Abstract This report describes the synthesis of a new NNSe pincer ligand and its mono‐ dinuclear palladium(II) complexes. In absence base, palladium complex ( C1 ) was isolated, while in presence Et 3 N base mononuclear C2 obtained. The complexes were characterized using techniques like 1 H, 13 C{ H} nuclear magnetic resonance (NMR), fourier transform infrared (FTIR), high‐resolution mass spectrometry (HRMS), ultraviolet‐visible (UV‐Visible), cyclic voltammetry. Both showed coordination mode with distorted square planar geometry. has two ligands attached through Pd−Pd bond fashion. air moisture‐insensitive, thermally robust used as catalyst for decarboxylative direct C−H heteroarylation (hetero)arenes. Among complexes, better catalytic activity. A variety (hetero)arenes successfully activated (43–87 % yield) only 2.5 mol loading under mild reaction conditions. PPh Hg poisoning experiments suggested homogeneous nature catalysis. plausible pathway proposed catalyzed activation

Language: Английский

Citations

9
Synthesis and Alkyne Metathesis Activity of Pincer Rhenium Carbyne Complexes DOI
Long Yiu Tsang, Wei Bai, Lam Cheung Kong

et al.

Organometallics, Journal Year: 2024, Volume and Issue: 43(8), P. 849 - 858

Published: April 10, 2024

While alkyne metathesis reactions involving d0 carbynes (alkylidynes) are well documented, those well-defined non-d0 still rare. This work reports the synthesis and activity of d2 Re(V) carbyne complexes supported by a [LXL]-type monoanionic [PNP]-pincer ligand, [LLX]-type [PNO]-pincer [ONOH]-bidentate ligand derived from Schiff base 2-[(2-hydroxyphenyl)iminomethyl]phenol. Treatment Re(≡CCH2Ph)Cl2(PMePh2)3 (1) with bis(2-diphenylphosphino-4-tolyl)amine (PNHP) 2-{(2-diphenylphosphino-phenyl)iminomethyl}phenol (PNOH) in presence NEt3 produced pincer Re(≡CCH2Ph)Cl(PMePh2)(PNP) (2) Re(≡CCH2Ph)Cl(PMePh2)(PNO) (3), respectively. The 2-[(2-hydroxyphenyl)iminomethyl]phenol (HONOH) reacted to give complex Re(≡CCH2Ph)Cl(PMePh2)(ONOH) (4) (ONOH = o-O-C6H4–CH═N-(o-C6H4OH)) bearing ligand. [PNP]- catalytically active for homometathesis neat 1-methoxy-4-(1-propyn-1-yl)benzene at 150 °C, while is inactive under similar conditions. energy profiles model rhenium alkyne-carbyne have been calculated DFT methods.

Language: Английский

Citations

2
Co‐Catalyzed Dehydrogenation Claisen Condensation of Secondary Alcohols with Esters† DOI
Shuo Gao, Wentao Hao,

Yuqi Ji

et al.

Chinese Journal of Chemistry, Journal Year: 2024, Volume and Issue: 42(22), P. 2818 - 2824

Published: July 17, 2024

Comprehensive Summary Catalytic dehydrogenation, with its exceptional atom economy and chemoselectivity, offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules. Furthermore, the utilization of catalysts based on abundant elements found Earth alcohol dehydrogenation to produce acryl ketone holds significant promise as versatile strategy in synthesizing key building blocks numerous pharmaceutical applications. The present study describes practical Co‐catalyzed cascade dehydrogenative Claisen condensation secondary esters, facilitating synthesis wide range 3‐hydroxy‐prop‐2‐en‐1‐ones. We introduce catalytic system novel scalable indazole NNP‐ligands coordinated cobalt efficient dehydrogenations alcohols, propose plausible reaction mechanism supported by control experiments labeling studies. Notably, it allows streamlined pharmaceuticals one‐pot.

Language: Английский

Citations

2