Phosphine (oxide)‐(thio) phenolate palladium complexes: Synthesis, characterization and (co)polymerization of norbornene

Zhang, Yanping; Mu, Hongliang; Li, Yanguo; Li, Yuesheng

doi:10.1002/aoc.4013

Cited by 10 publications

(1 citation statement)

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“…The vinyl polymerization of norbornene (NB) has attracted considerable attention due to the outstanding performance of polynorbornenes, with attributes such as a high optical transparency, a high chemical resistance, a high glass transition temperature, a low birefringence, etc. − To date, although extensive early- and late-transition-metal catalytic systems have been reported to promote the polymerizations, very few of them were able to be carried out under high temperature conditions, largely owing to the inferior thermal stabilities of the active species. − Considering the high turnover numbers (TONs) and therefore the rapid and strong exothermicity that were encountered during the previous polymerization studies (some polymerizations were accomplished even within a few minutes), addressing the thermal stability issues becomes very essential.…”

Section: Resultsmentioning

confidence: 99%

Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness

et al. 2021

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Increasing the thermostability of α-diimine late-transition-metal complexes and therefore rendering them more active at higher temperatures is of great importance, yet challenging for the olefin polymerization field. In the present research, a new family of α-diimine palladium complexes that can promote norbornene polymerization at high temperatures (up to 140 °C) is disclosed. Because of the conformational restriction caused by increasing the axial and equatorial bulkiness as well as the presence of intraligand H···F hydrogen bonds, N-aryl rotations can be efficiently restricted, therefore circumventing the deactivation of the active species at high temperatures. At 80–140 °C, these complexes can efficiently catalyze norbornene homopolymerizations, giving high catalytic activities up to 5.65 × 107 g of PNB per mole Ni per hour and polymers with high molecular weights up to 37.2 × 104 g/mol, which are highly superior to catalytic systems mediated by CF3-free complexes. Moreover, these complexes could also afford medium catalytic activities in the presence of polar 5-norbornene-2-carboxylic acid methyl ester (NB-COOCH3).

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Section: Resultsmentioning

confidence: 99%

Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness

et al. 2021

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Diverse Catalytic Applications of Phosphine Oxide‐Based Metal Complexes

Vijai Anand,

Perinbanathan,

Singh

et al. 2024

ChemCatChem

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Phosphine oxides are an interesting class of compounds possessing tetracoordinate and pentavalent phosphorus atoms and have been employed in a wide range of applications including reagents in organic synthesis, metal extractants, flame retardants, pharmaceuticals, and bioactivity studies. Among all, the degree of basicity of phosphoryl oxygen driven by the nature of substituents influences the electronic properties of the central metal in a complex toward the diversified catalytic processes. Further, the presence of heteroatoms adjacent to the central phosphorus atom enhances the nucleophilicity of the phosphoryl oxygen atom. In view of this, the present review covers the past two decades of remarkable catalytic versatility of P=O‐based metal complexes and describes the governing factors influencing the structural properties and the resultant coordination behavior. Interestingly, some of the P=O bond distances of metal complexes are either longer or shorter compared to their free ligands, indicating the catalytic activity. These complexes can effectively catalyze a wide range of chemical reactions including polymerizations, C‐C and Si‐C bond activations, oxidation, reduction, hydroformylation, hydrophosphination, hydrogenation and cyclization reactions. Furthermore, this review emphasizes the impact of substituents, solvents, additives, light, and temperature on the catalytic efficiency.

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Crystallinity in quasi‐alternating cycloolefin copolymers: Overcoming brittleness

Moon

Park

Baek

et al. 2020

Journal of Polymer Science

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Cycloolefin copolymers (COCs, which are produced via ethylene/cycloolefin copolymerization) and cycloolefin polymers (COPs, which are synthesized by a rather complicated two‐step process via ring‐opening metathesis polymerization and subsequent hydrogenation) are commercialized materials used especially widely in optical applications. Although a COP can be used after processing into a film, films made from conventional COCs are too brittle. Optical‐grade COCs and COPs are generally known as amorphous polymers. By contrast, here, a quasi‐alternating ethylene/norbornene copolymer (norbornene content 56 mol%), prepared from a constrained‐geometry Hf complex, shows some melting (Tm) signals in a broad temperature range (150–200°C) in the first heating scan of differential scanning calorimetry (DSC) when the samples are prepared by precipitation from a toluene solution. In the second heating scan, only glass transition (Tg) signals are observed at ~140°C with disappearance of Tm signals. The quasi‐alternating ethylene/norbornene copolymer has better mechanical properties (greater elongation at break) than random congeners, which do not show any melting signal, though elongation at break is still inferior to that of the COP which shows the melting signal in the first heating scan of DSC. The enhanced mechanical properties of the quasi‐alternating ethylene/norbornene copolymer and commercial‐grade COP may be ascribed to semicrystallinity observed in the first heating scan.

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Phosphine (oxide)‐(thio) phenolate palladium complexes: Synthesis, characterization and (co)polymerization of norbornene

Cited by 10 publications

References 53 publications

Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness

Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness

Diverse Catalytic Applications of Phosphine Oxide‐Based Metal Complexes

Crystallinity in quasi‐alternating cycloolefin copolymers: Overcoming brittleness

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