High-throughput Acid-Base Tandem Organocatalysis over Hollow Tube-Shaped Porous Polymers and Carbons

Modak, Arindam; Bhaumik, Asim

doi:10.1002/slct.201600239

Cited by 30 publications

(21 citation statements)

References 83 publications

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“…Since NPs have 2.8‐4 nm dimensions and micropores are < 2 nm, therefore NPs are possibly deposited at the surface or in the interparticle mesopores of the nanotube. The presence of interparticle mesopores has been observed from the steep rise of the isotherm at high P/P 0 (0.9) and is also indicating from desorption hysteresis . In order to determine the state of NPs, X‐ray photoelectron spectroscopy (XPS) was used to characterize Pd and Pt core level spectra (Figure d).…”

Section: Resultsmentioning

confidence: 99%

Pt and Pd Nanoparticles Immobilized on Amine-Functionalized Hypercrosslinked Porous Polymer Nanotubes as Selective Hydrogenation Catalyst for α,β-Unsaturated Aldehydes

2017

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Selective hydrogenation reaction over supported metal nanoparticles (NPs) through activation of molecular H2 is very demanding in the context of maintaining atom efficiency in chemical reactions. Although high selectivity is difficult to achieve in the reaction, but it is very challenging. In this research, we separately deposited Pd and Pt NPs on nanoporous hollow polymer tubes (PP‐3) and studied their efficiency in hydrogenation of α,β‐unsaturated aldehydes as substrates. We found hydrogenation selectivity over these two types of catalysts (Pd@PP‐3 and Pt@PP‐3) were entirely different. Pt@PP‐3 shows high selectivity in the hydrogenation of C=O bonds, producing unsaturated alcohol in high yield, whereas Pd@PP‐3 only hydrogenates C=C bonds and forms saturated aldehyde as the major product. Pd@PP‐3 and Pt@PP‐3 were thoroughly characterized by PXRD, N2 sorption, TEM, XPS, CO stripping experiment and in‐situ CO adsorption FT‐IR studies. Our research implies the utility of porous organic polymers as support for metal NPs mediated hydrogenation reactions.

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Section: Resultsmentioning

confidence: 99%

Pt and Pd Nanoparticles Immobilized on Amine-Functionalized Hypercrosslinked Porous Polymer Nanotubes as Selective Hydrogenation Catalyst for α,β-Unsaturated Aldehydes

2017

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“…Porous, template-free COPs with uniform tube morphology have been used for device manufacturing [16] and catalysis, [17,18] but reports of the synthesis and application of this type of material remain scarce. Studies of covalent nanosheets are more prevalent, but, this type of material is obtained by either liquid phase exfoliation [19] or mechanical delamination, [20] and these two methods often result in low surface areas because the mechanical forces involved often cause pore blockage.…”

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confidence: 99%

Morphological Diversity in Nanoporous Covalent Organic Materials Derived from Viologen and Pyrene

Das¹,

Škorjanc²,

Sharma

et al. 2017

ChemNanoMat

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Adjustment of the morphology of covalent organic nanomaterials is a challenge but can be achieved by perturbing the planarity of the monomers used as core moieties in these polymers. Here we describe a templatefree Zincke reaction for the synthesis of covalent organic nanosheets (CONs) that stack several layers thick and of covalent organic tubes (COTs). Both materials contain the same viologen linker but different pyrene-based cores. Both polymeric materials are nanoporous, cationic, and highly stable in water, even in the presence of acid (1 M HCl) or base (1 M NaOH). Their porosity and ionic surfaces are responsible for high affinities and adsorption capacities for iodine vapor.Porous covalent organic polymers (COPs) are well known for their diverse applications in fields such as gas storage and separation, [1][2][3][4] catalysis, [5][6][7][8] sensing, [9,10] drug delivery, [11] and environmental remediation. [12] In order to design COPs with improved functionality, considerable research has been undertaken to understand the relationship between the morphologies and properties of these materials. [13][14][15] It has been observed that the morphology of COPs can be tuned by changing the symmetry of their constituent building blocks, but precise regulation of COP nanostructure remains a challenging task.Syntheses of covalent organic hollow tubes (COTs) and nanosheets (CONs) are of interest because their large surface areas facilitate the adsorption of small molecule guests. Porous, template-free COPs with uniform tube morphology have been used for device manufacturing [16] and catalysis, [17,18] but reports of the synthesis and application of this type of material remain scarce. Studies of covalent nanosheets are more prevalent, but, this type of material is obtained by either liquid phase exfoliation [19] or mechanical delamination, [20] and these two methods often result in low surface areas because the mechanical forces involved often cause pore blockage. In short, syntheses that rely on mechanical techniques for isolating nanosheets tend to be expensive and non-scalable and produce materials that have limited adsorption efficiency. Designing an efficient and green approach to the large-scale synthesis of porous CONs stacked several (or fewer) layers thick is an open challenge. [21] In general, porous COPs are synthesized from neutral building blocks, which limits the range of application for the materials. For example, neutral COPs are not optimal for the uptake of charged species, including toxic ionic guest molecules. To address this issue, we have begun to develop charged COPs that incorporate redox-active viologens and are capable of adsorbing iodine vapor, toxic dyes, and metal ions by anion exchange. [22,23] Despite their great potential, viologen-based COPs are still rarely documented in the literature, though Li et al. [24] have reported supramolecular organic frameworks (SOFs) that contain viologen struts and form in water.Herein, we report a one-pot, template-free solvothermal synthesis ...

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“…Synthesis of PP-3 was followed in accordance with a previously reported procedure [24]. For the preparation of Pd/PP-3, we initially dissolved 0.010 g of palladium acetate in a 20 mL glass vial containing 10 mL of distilled water and stirred until the solution became yellow.…”

Section: Methodsmentioning

confidence: 99%

“…The size of the organic tubes are found to be ~5-7 μm in length, and the inner hollow diameter is ~80-100 nm, together with ~300-350 nm is the wall thickness. This thickness accounts for excessive polymerization/non-covalent interaction, which is due to the addition of a large quantity of DMM linker during the synthesis [24]. Pd immobilization to PP-3 was performed by loading with Pd(OAc)2, followed by a reduction with aqueous NaBH4 under mild conditions.…”

Section: Synthesis and Characterization Of Pd/pp-3 Tubesmentioning

confidence: 99%

“…Nevertheless, POPs having uniform morphology of hollow tubes/fibers are still scarce; moreover, their application is merely limited to device manufacturing [23]. Recently, Modak and Bhaumik reported interesting microporous polymer tubes (PP-1, PP-2, PP-3; PPs) that are uniform and show high heterogeneity for one-pot tandem catalysis [24]. However, PPs could also be interesting as support for metal nanoparticles' owing to their amine functionality; therefore, we investigated its activity for SuzukiMiyaura cross coupling reactions.…”

Section: Introductionmentioning

confidence: 99%

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Palladium Nanoparticles Tethered in Amine-Functionalized Hypercrosslinked Organic Tubes as an Efficient Catalyst for Suzuki Coupling in Water

et al. 2016

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It is highly desirable to design functionalized supports in heterogeneous catalysis regarding the stabilization of active sites. Pd immobilization in porous polymers and henceforth its application is a rapidly growing field. In virtue of its' scalable synthesis and high stability in reaction conditions, amorphous polymers are considered an excellent scaffold for metal mediated catalysis, but the majority of them are found as either agglomerated particles or composed of rough spheres. Owing to several important applications of hollow organic tubes in diverse research areas, we aimed to utilize them as support for the immobilization of Pd nanoparticles. Pd immobilization in nanoporous polymer tubes shows high activity in Suzuki cross coupling reactions between aryl halides and sodium phenyl trihydroxyborate in water, which deserves environmental merit.

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High-throughput Acid-Base Tandem Organocatalysis over Hollow Tube-Shaped Porous Polymers and Carbons

Cited by 30 publications

References 83 publications

Pt and Pd Nanoparticles Immobilized on Amine-Functionalized Hypercrosslinked Porous Polymer Nanotubes as Selective Hydrogenation Catalyst for α,β-Unsaturated Aldehydes

Pt and Pd Nanoparticles Immobilized on Amine-Functionalized Hypercrosslinked Porous Polymer Nanotubes as Selective Hydrogenation Catalyst for α,β-Unsaturated Aldehydes

Morphological Diversity in Nanoporous Covalent Organic Materials Derived from Viologen and Pyrene

Palladium Nanoparticles Tethered in Amine-Functionalized Hypercrosslinked Organic Tubes as an Efficient Catalyst for Suzuki Coupling in Water

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