Controlling the Coordination Modes of Pyridyl-Functionalized N-Heterocyclic Dicarbene Ligands

Huynh, Han Vinh; Chia, Sara Shuen Hui; Leong, Nicholas Yew Sheng

doi:10.1021/acs.organomet.0c00587

Cited by 5 publications

(3 citation statements)

References 21 publications

(49 reference statements)

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“…Moreover, N-containing heterocyclic ligands have received intense attention due to their strong coordination affinity to the first-row transition metal ions 6 and their diverse coordination modes. 7 Recent advances in the field of SMMs have shown that 3d metal-based SMMs are still worth pursuing. 8 The oxygen evolution reaction (OER) from water splitting exhibits great promise for clean energy production and shows high potential for replacing conventional fossil fuels.…”

Section: Introductionmentioning

confidence: 99%

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Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Zhang

Yang

et al. 2022

New J. Chem.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Zhang

Yang

et al. 2022

New J. Chem.

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“…[ 41,42 ] The stability of these complexes can be further enhanced by the thermodynamic chelate effect such as the case of the chelating bis(NHCs). [ 43–47 ]…”

Section: Introductionmentioning

confidence: 99%

Robust alkyl‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones

Mansour

Fettouhi

Saleem

et al. 2021

Applied Organom Chemis

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Highly active and efficient propylene‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes covalently anchored on Merrifield's resin were synthesized and characterized using various physical and spectroscopic techniques. The two anchored Pd(II) complexes consist of the system: Merrifield's resin‐linker‐bis(NHC)Pd(II), the linkers being benzyl and benzyl‐O‐(CH2)3 for (Pd‐NHC1@M) and (Pd‐NHC2@M), respectively. The short linker anchored bis‐benzimidazolium ligand precursor (PBBI‐1@M) was synthesized via direct carbon–nitrogen alkylation of a propylene‐bridged bis(benzimidazole) (PBBI‐1) by Merrifield's resin chlorobenzyl group. The longer linker anchored bis‐benzimidazolium ligand precursor (PBBI‐2@M) was obtained in a two‐step reaction involving first alkylation of (PBBI‐1) with 3‐chloro‐1‐propanol followed by a nucleophilic substitution at Merrifield's resin chlorobenzyl group. Both supported ligand precursors (PBBI‐1@M and PBBI‐2@M) reacted with palladium acetate to produce the two heterogeneous catalysts (Pd‐NHC1@M) and (Pd‐NHC2@M). 13C NMR palladation shift of the benzimidazole N–C–N (C2) carbon was found very similar in both the liquid NMR spectra of the homogeneous complexes and the CP/MASS spectra of the corresponding covalently anchored complexes. The catalytic activity, stability, and the recycling ability of the supported catalysts have been investigated in the carbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes and alkyl alkynes and also in the cyclocarbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes via one pot reactions. The longer linker catalyst Pd‐NHC2@M demonstrated excellent catalytic activity, stability, and very high recycling ability in the two carbonylative coupling reactions. These systems exhibit the hypothesized thermodynamic stability offered by the chelate effect in addition to the strong sigma donor ability of a bis(NHC) ligand system generating electron‐rich palladium centers that favor the oxidative addition step of the aryl halide.

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Palladium hetero‐di(N‐heterocyclic carbene) complexes and their catalytic activities in direct C–H arylation of heteroarenes

Ghatak

Huynh

2022

Applied Organom Chemis

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A library of neutral and cationic palladium complexes of cis‐chelating hetero‐dicarbene ligands have been prepared. These ligands contain two different NHC donors allowing for a wider degree of variation, and the impact of the distinct NHC units has been compared using various spectroscopic means. In addition, the catalytic activities of these complexes in the direct C‐H arylation of thiophenes with aryl halides were studied leading to the finding that the neutral dibromido complexes of the type [PdBr2(diNHC)] generally outperformed their cationic [Pd (NCMe)2(diNHC)](OTf)2 counterparts. More importantly, complexes containing more distinct NHC units give rise to superior catalysts due to an amplified “stereoelectronic asymmetry” within the complex. A preliminary photophysical study of some selected thiophene reaction products has been conducted as well. The ability to individually change each NHC donor in such dicarbene ligands allows for a better fine‐tuning of complex properties in search for superior catalysts.

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Controlling the Coordination Modes of Pyridyl-Functionalized N-Heterocyclic Dicarbene Ligands

Cited by 5 publications

References 21 publications

Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Robust alkyl‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones

Palladium hetero‐di(N‐heterocyclic carbene) complexes and their catalytic activities in direct C–H arylation of heteroarenes

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Controlling the Coordination Modes of Pyridyl-Functionalized N-Heterocyclic Dicarbene Ligands

Cited by 5 publications

References 21 publications

FeII, CoII and NiII complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

FeII, CoII and NiII complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Robust alkyl‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones

Palladium hetero‐di(N‐heterocyclic carbene) complexes and their catalytic activities in direct C–H arylation of heteroarenes

Contact Info

Product

Resources

About

Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties

Fe^II, Co^II and Ni^II complexes based on 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine: synthesis, structures, single-molecule magnetic and electrocatalytic properties