N-heterocyclic carbene bearing thermoresponsive poly(NIPAM) supported palladium (II) complex: Synthetic strategy and application

Pentela, Nagaraju; Gayathri, Varnakumar; Samanta, Debasis

doi:10.1016/j.jorganchem.2020.121196

Cited by 11 publications

(9 citation statements)

References 52 publications

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“…As we have reported in our previous works, in the case of the PNIPAM-NHC-Pd (II) complex (catalyst A), the breakage of the NHC-Pd bond will occur at 217 C, which is higher than the experimental temperature value (170-190 C). 22 Whereas on the other hand, in the case of PNIPAM-NHC-Pd (0) (catalyst B), such breaking of NHC-Pd bond starts from a much lower temperature, around 182 C, which is close to the experimental temperature. 19 Thus, as a result, catalyst B can easily produce the effective PNIPAM-Nheterocyclic carbenes in situ during the experimental conditions, which will aid the glycolysis of PET.…”

Section: Synthesis Of the Bis(2-([4-butoxy Benzoyl]oxy)ethyl) Terepht...mentioning

confidence: 52%

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Gayathri

Sheyara

Devassy

et al. 2022

J of Applied Polymer Sci

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Herein we have reported the effective use of palladium‐based systems which contain modified N‐Heterocyclic carbene (NHC) tagged with poly(N‐isopropylacrylamide) (PNIPAM) moiety as an organometallic catalyst. This report involves a comparative study between two catalysts, PNIPAM‐NHC‐Pd (II) complex (catalyst A) and PNIPAM‐NHC‐Pd (0) nanoparticles (catalyst B), to participate in the degradation of poly(ethylene terephthalate) (PET) into its monomer, bis(2‐hydroxyethyl terephthalate) (BHET) through glycolysis with ethylene glycol (EG). Glycolysis of the PET was carried out at different temperatures (170, 175, 180, 185, and 190°C) and times (6 and 24 h) where optimum results were obtained while glycolysis was performed at 180°C for 24 h using catalyst B. The investigation of the glycolysis product through NMR, ATR‐IR, TGA, and DSC proved the formation of BHET as the main product. To ensure the effective recycling of the PET and further value additions, the obtained glycolysis product, BHET was further transformed into its dibenzoylated derivative, bis(2‐([4‐Butoxy benzoyl]oxy)ethyl) terephthalate (BBET) by successive benzoylation using 4‐butoxybenzoyl chloride. The obtained BBET was used as an additive along with the commercial polyurethane‐based adhesive (CPU), and its effect on the properties of CPU was investigated using differential scanning calorimetry (DSC) studies.

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Section: Synthesis Of the Bis(2-([4-butoxy Benzoyl]oxy)ethyl) Terepht...mentioning

confidence: 52%

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Gayathri

Sheyara

Devassy

et al. 2022

J of Applied Polymer Sci

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“…As depicted in Scheme 1, thermoresponsive NHC‐capped palladium NPs were synthesized using PNIPAM‐tagged NHC precursor ( 1 ), which was synthesized using the procedure borrowed from our previous work. [ 38 ] Two different “Bottom‐up” approach has been employed for the successful formation of thermoresponsive NHC‐capped Pd NPs (catalysts 2 and 4) from the NHC precursor ( 1 ). In method A, Pd (OAc) 2 and DMSO were used to synthesize palladium NPs, [ 34 ] where both the formation of NHC–Pd (II) complex and reduction into PNIPAM–NHC–Pd (0) NPs (catalyst 2) take place in a single step.…”

Section: Resultsmentioning

confidence: 99%

“…For 4‐iodoacetophenone substrate (Entry 1—Table 1), both the catalysts showed high catalytic activity to yield >90% of conversion, which was comparatively higher than our previous work. [ 38 ] Furthermore to extend the scope of the substrates, coupling reactions of different aryl substrates such as with activating R groups (OH, CH 3 ) or deactivating R groups (COCH 3 , COOH) were carried out under the same condition and their percentage of conversion was tabulated in Table 1. As expected, chloro‐based substrate gave very low conversion (Entry 3) due to the strong C–Cl bond.…”

Section: Resultsmentioning

confidence: 99%

“…To overcome those problems, we recently designed various thermoresponsive organometallic catalysts, [ 29,38 ] which offer the advantage of both homogeneous and heterogeneous catalysts where the catalytic reactions can be performed in the homogeneous condition under ambient temperature followed by recovery at elevated temperature due to temperature‐dependent phase separations in water. To improve the recovery, herein we report palladium NPs with thermoresponsive NHC ligands using two different methods.…”

Section: Introductionmentioning

confidence: 99%

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Palladium nanoparticles capped by thermoresponsive N‐heterocyclic carbene: Two different approaches for a comparative study

Gayathri

Pentela

Samanta

2021

Applied Organom Chemis

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In this article, we reported the synthesis of thermoresponsive palladium nanoparticles, stabilized by polymer‐tagged N‐heterocyclic carbenes (NHCs), using two different approaches. In one case, the nanoparticles were synthesized from the NHC–palladium complex, while in other cases, palladium nanoparticles and NHC were synthesized simultaneously for the in situ cappings of the nanomaterial. While the thermoresponsive nature of the nanomaterials was observed in both cases, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analyses showed distinct characteristics in the thermal behavior of those materials. High‐resolution transmission electron microscopic (HRTEM) and scanning electron microscopic studies separately revealed temperature‐dependent aggregation in both cases although separate patterns were observed when the nanomaterials were synthesized using different approaches. Finally, both the nanomaterials were successfully used as a recyclable catalyst for Suzuki reactions in an aqueous medium, with slightly different catalytic activity, plausibly due to variations in the size of the nanoparticles.

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“…There are some recent advances reported where smart polymers are involved in the preparation of hybrid materials for heterogeneous catalysis, which offer some advantages in terms of easy separations and recyclability [21][22][23]. However, applications can be extended to other fields as biomedical applications [8,[24][25][26][27][28] or nanotechnology [29].…”

Section: Introductionmentioning

confidence: 99%

Concentration Effect over Thermoresponse Derived from Organometallic Compounds of Functionalized Poly(N-isopropylacrylamide-co-dopamine Methacrylamide)

et al. 2021

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The functionalization of smart polymers is opening a new perspective in catalysis, drug carriers and biosensors, due to the fact that they can modulate the response regarding conventional devices. This smart response could be affected by the presence of organometallic complexes in terms of interactions which could affect the physical chemical properties. In this sense, the thermoresponsive behavior of copolymers based on N-isopropylacrylamide (NIPAM) could be affected due to the presence of hydrophobic groups and concentration effect. In this work, the functionalization of a copolymer based on NIPAM and dopamine methacrylamide with different amounts of bis(cyclopentadienyl)titanium (IV) dichloride was carried out. The resulting materials were characterized, showing a clear idea about the mechanism of functionalization through FTIR spectroscopy. The thermoresponsive behavior was also studied for various polymeric solutions in water by UV–vis spectroscopy and calorimetry. The hydrophobic interactions promoted by the organometallic complex could affect the transition associated with the lower critical solution temperature (LCST), specifically, the segments composed by pure NIPAM. That fact would explain the reduction of the width of the LCST-transition, contrary to what could be expected. In addition, the hydrophobicity was tested by the contact angle and also DNA interactions.

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N-heterocyclic carbene bearing thermoresponsive poly(NIPAM) supported palladium (II) complex: Synthetic strategy and application

Cited by 11 publications

References 52 publications

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Palladium nanoparticles capped by thermoresponsive N‐heterocyclic carbene: Two different approaches for a comparative study

Concentration Effect over Thermoresponse Derived from Organometallic Compounds of Functionalized Poly(N-isopropylacrylamide-co-dopamine Methacrylamide)

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