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Škoch K, Antala J, Císařová I, Štěpnička P. Synthesis and catalytic properties of palladium(II) complexes with P,π-chelating ferrocene phosphinoallyl ligands and their non-tethered analogues. Dalton Trans 2024; 53:8722-8731. [PMID: 38712379 DOI: 10.1039/d4dt00961d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Hybrid phosphines usually combine a phosphine moiety with another heteroatom secondary donor group in their structures while compounds equipped with hydrocarbyl π-donor moieties remain uncommon. This contribution reports the synthesis and structural characterization of the first P/π-allyl-chelating complexes that were obtained using the structurally flexible and redox-active ferrocene unit as the scaffold, viz. [PdCl(R2PfcCHCHCH2-η3:κP)] (1R; R = Ph and cyclohexyl (Cy); fc = ferrocene-1,1'-diyl). These compounds were synthesized from the respective phosphinoferrocene carboxaldehydes R2PfcCHO via reaction with vinylmagnesium bromide to generate 1-(phosphinoferrocenyl)allyl alcohols, which were subsequently acetylated. The resulting allyl acetates reacted smoothly with [Pd2(dba)3]/[Et3NH]Cl (dba = dibenzylideneacetone) to produce the target compounds. Complexes 1R and their nontethered analogues [PdCl(η3-C3H5)(FcPR2-κP)] (5R; Fc = ferrocenyl) were evaluated as pre-catalysts for the Pd-catalysed allylic amination of cinnamyl acetate with aliphatic amines and Suzuki-Miyaura-type cross-coupling of 4-tolylboronic acid with benzoyl chloride. In these reactions, better results were achieved with compounds 5R (particularly with 5Ph), presumably because they form more stable LPd(0)-type catalysts.
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Affiliation(s)
- Karel Škoch
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež, Czech Republic
| | - Jakub Antala
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Petr Štěpnička
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
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Hood TM, Lau S, Chaplin AB. Capture of mechanically interlocked molecules by rhodium-mediated terminal alkyne dimerisation. RSC Adv 2024; 14:7740-7744. [PMID: 38444978 PMCID: PMC10914095 DOI: 10.1039/d4ra00566j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
The transition metal-mediated dimerisation of terminal alkynes is an attractive and atom-economic method for preparing conjugated 1,3-enynes. Using a phosphine-based macrocyclic pincer ligand, we demonstrate how this transformation can be extended to the synthesis of novel, hydrocarbon-based interlocked molecules: a rotaxane by 'active' metal template synthesis and a catenane by sequential 'active' and 'passive' metal template procedures.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
| | - Samantha Lau
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
| | - Adrian B Chaplin
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
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Emerson-King J, Pan S, Gyton MR, Tonner-Zech R, Chaplin AB. Synthesis of a rhodium(III) dinitrogen complex using a calix[4]arene-based diphosphine ligand. Chem Commun (Camb) 2023; 59:2150-2152. [PMID: 36727440 PMCID: PMC9933454 DOI: 10.1039/d2cc06837k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The synthesis and characterisation of the rhodium(III) dinitrogen complex [Rh(2,2'-biphenyl)(CxP2)(N2)]+ are described, where CxP2 is a trans-spanning calix[4]arene-based diphosphine and the dinitrogen ligand is projected into the cavity of the macrocycle.
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Affiliation(s)
- Jack Emerson-King
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Sudip Pan
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität LeipzigLinnéstraße 2LeipzigD-04103Germany
| | - Matthew R. Gyton
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Ralf Tonner-Zech
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität LeipzigLinnéstraße 2LeipzigD-04103Germany
| | - Adrian B. Chaplin
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventryCV4 7ALUK
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Poole EW, Bustos I, Hood TM, Smart JE, Chaplin AB. Iridium complexes of an ortho-trifluoromethylphenyl substituted PONOP pincer ligand. Dalton Trans 2023; 52:1096-1104. [PMID: 36602231 PMCID: PMC9872493 DOI: 10.1039/d2dt03608h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis and iridium coordination chemistry of a new pyridine-based phosphinito pincer ligand 2,6-(ArF2PO)2C5H3N (PONOP-ArF; ArF = 2-(CF3)C6H4) are described, where the P-donors have ortho-trifluoromethylphenyl substituents. The iridium(III) 2,2'-biphenyl (biph) derivative [Ir(PONOP-ArF)(biph)Cl] was obtained by reaction with [Ir(biph)(COD)Cl]2 (COD = 1,5-cyclooctadiene) and subsequent halide ion abstraction enabled isolation of [Ir(PONOP-ArF)(biph)]+ which features an Ir ← F-C bonding interaction in the solid state. Hydrogenolysis of the biphenyl ligand and formation of [Ir(PONOP-ArF)(H)2]+ was achieved by prolonged reaction of [Ir(PONOP-ArF)(biph)]+ with dihydrogen. This transformation paved the way for isolation and crystallographic characterisation of low valent iridium derivatives through treatment of the dihydride with tert-butylethylene (TBE). The iridium(I) π-complex [Ir(PONOP-ArF)(TBE)]+ is thermally stable but substitution of TBE can be achieved by reaction with carbon monoxide. The solid-state structure of the mono-carbonyl product [Ir(PONOP-ArF)(CO)]+ is notable for an intermolecular anagostic interaction between the metal centre and a pentane molecule which co-crystallises within a cleft defined by two aryl phosphine substituents.
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Affiliation(s)
- Ethan W. Poole
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Itxaso Bustos
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK,Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU)Apdo. 107220080 San SebastiánSpain
| | - Thomas M. Hood
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Jennifer E. Smart
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Adrian B. Chaplin
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
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Parker GL, Van Lommel R, Roig N, Alonso M, Chaplin AB. Modulation of Metal Carbonyl Stretching Frequencies in the Second Coordination Sphere through the Internal Stark Effect. Chemistry 2022; 28:e202202283. [PMID: 36082961 PMCID: PMC10092048 DOI: 10.1002/chem.202202283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Indexed: 12/14/2022]
Abstract
Spectroscopic and computational examination of a homologous series of rhodium(I) pybox carbonyl complexes has revealed a correlation between the conformation of the flanking aryl-substituted oxazoline donors and the carbonyl stretching frequency. This relationship is also observed experimentally for octahedral rhodium(III) and ruthenium(II) variants and cannot be explained through the classical, Dewar-Chatt-Duncanson, interpretation of metal-carbonyl bonding. Instead, these findings are reconciled by local changes in the magnitude of the electric field that is projected along the metal-carbonyl vector: the internal Stark effect.
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Affiliation(s)
- Gemma L Parker
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK
| | - Ruben Van Lommel
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium.,Molecular Design and Synthesis, Department of Chemistry, KU Leuven, 3001, Leuven, Belgium
| | - Nil Roig
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK.,Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium
| | - Mercedes Alonso
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium
| | - Adrian B Chaplin
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK
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Takimoto K, Watanabe Y, Yoshida J, Sato H. Five-coordinate iridium(III) complex with ΔΛ chirality. Dalton Trans 2021; 50:13256-13263. [PMID: 34608912 DOI: 10.1039/d1dt01960k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The coordinatively unsaturated bis-chelated iridium(III) complex, [Ir(2-Bubzq)2Cl] (2-BubzqH = 2-butyl-benzo[h]quinoline), denoted as complex 1, was obtained by reacting iridium(III) trichloride with 2-BubzqH in a 1 : 2 molar ratio. The results were in contrast to the common view that a chlorine-bridged dimer, [Ir(L)2Cl]2 (L = bis-chelate ligand), is formed under the corresponding conditions. A single-crystal X-ray diffraction structural analysis revealed that complex 1 has a five-coordinate geometry with a distorted square pyramidal configuration. The optical resolution of complex 1 was measured chromatographically on a chiral column, yielding Δ and Λ as enantiomers. The resolved enantiomers were stable enough against racemization in CDCl3 as confirmed by the vibrational circular dichroism measurements. Complex 1 reacted with carbon monoxide (CO) to give [Ir(2-Bubzq)2(CO)Cl] and with 1,10-phenanthroline (phen) to give [Ir(2-Bubzq)2(phen)]Cl within a minute with its absolute configuration (ΔΛ chirality) maintained.
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Affiliation(s)
- Kazuyoshi Takimoto
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-chou, Matsuyama, Ehime 790-8577, Japan.
| | - Yutaka Watanabe
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-chou, Matsuyama, Ehime 790-8577, Japan.
| | - Jun Yoshida
- Department of Chemistry, College of Humanities & Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan
| | - Hisako Sato
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-chou, Matsuyama, Ehime 790-8577, Japan.
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