Palladium‐Nanoparticle‐Linked Organic Frameworks: Heterogeneous Recyclable Catalysts in Aqueous Medium

Abstract

4,4′‐Biphenylene‐bisdiazonium tetrafluoroborate and a palladium salt were reduced simultaneously to result in the formation of palladium atoms and 4,4′‐biphenylene biradicals. The palladium atoms underwent clustering forming palladium nanoparticles, whereas the 4,4′‐biphenylene biradicals underwent rapid addition reactions to other radicals and also to nanoparticle surfaces. The resulting product contains palladium nanoparticles covalently linked to an organic framework (PNOF). The effects of different reaction conditions upon metal content as well as on the morphology of the PNOF were studied. The PNOF structure was probed by different experimental techniques. The PNOFs were evaluated as heterogeneous recyclable catalyst in aqueous medium for reduction of 4‐nitrophenol and Suzuki coupling reactions. The catalyst exhibited high reactivity even in Suzuki couplings of aryl chlorides.

Highly Stable Copper Nanoparticles Linked to Organic Frameworks as Recyclable Catalyst for Three‐Component Click Cycloaddition in Water

“…The Cu 2p 1/2 peak was seen between 954–956 eV and the corresponding shake‐up satellite peak was observed between 964–966 eV. Previous studies have shown that metal nanoparticles stabilized by metal carbon covalent bonds will show M 2+ peak in the XPS . Similar results are obtained for CNOFs also.…”

“…As we go from CNOF1 to CNOF4 the metal content increased and the NMR signals became very broad. Broadening of NMR signals were observed previously in the case of nanoparticle cored dendrimers and palladium nanoparticle linked organic frameworks . The NMR line broadening arises due to the fast spin‐spin relaxation of atoms close to a metal.…”

“…A curve fitting program was used to deconvolute the C 1s, O 1s and Cu 2p peaks of CNOF. The C 1s peak observed in the 281–288 eV range could be deconvoluted adequately in to C−Cu (283.5 eV), C−C (284.5 eV), C−H (285.3 eV) and C−O‐Cu (286.3 eV) contributions. As we go from CNOF1 to CNOF4 intensity of the C−O‐Cu increases relative to the C−Cu peak suggesting that CNOF having higher metal content have more oxide content.…”

Gram‐Scale Bottom‐Up Synthesis of Macrographene

“…In this report we present a gram‐scale bottom‐up synthesis of macrographene wherein we have exploited the biradicals to undergo rapid addition reactions to give organic frameworks. Previously we have exploited this method to synthesize metal nanoparticle‐linked organic frameworks …”

Wool-anchored Pd(OAc)2 complex: a highly active and reusable catalyst for desulfurative coupling reactions

“…It is also a new and nevertheless robust 55 method of the transition-metal catalyzed synthesis in heterogeneous systems. [39][40][41][42][43][44][45][46] Studies 60 upon transition-metal complexes achieved tremendous progress, [47][48][49][50] and also inspired our explorations. and hybrid organic-inorganic (mainly grafted silica) supported transition-metal materials have been used in practice.…”