Iron Oxide Nanoparticles Modified with Carbon Quantum Nanodots for the Stabilization of Palladium Nanoparticles: An Efficient Catalyst for the Suzuki Reaction in Aqueous Media under Mild Conditions

Magnetic Fe3O4 nanoparticles (NPs) functionalized with carbon dots (C-dots) that contain carboxylic acid and hydroxyl groups were synthesized successfully and used for the reduction of PdII and the formation of Pd NPs. The new material was characterized by SEM, TEM, energy-dispersive spectroscopy, solid UV spectroscopy, vibrating sample magnetometry, XRD, and X-ray photoelectron spectroscopy and was used as a very efficient catalyst in the Suzuki–Miyaura cross-coupling reaction of aryl bromides and chlorides with arylboronic acids in aqueous media. Design of experiments indicates that the use of 0.22 mol % of Pd, K2CO3 as the base, and aqueous ethanol are the best reaction conditions. The reactions of aryl bromides take place at room temperature, and aryl chlorides react at 80 °C. The easily synthesized and air-stable catalyst Pd@C-dots@Fe3O4 NPs could be separated from the reaction mixture by using an external magnet and reused in eight consecutive runs with no significant loss of catalytic activity.The authors are grateful to the Institute for Advanced Studies in Basic Sciences (IASBS) and the Iran National Science Foundation (INSF-Grant number of 94010666) for support of this work. C.N. is grateful to the Spanish Ministerio de Economia y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), FEDER, the Generalitat Valenciana (PROMETEOII/2014/017), and the University of Alicante for financial support

Dispersible microporous di-block co-polymer Nanoparticles via polymerisation-induced self-assembly

Microporous materials are predominantly formed as insoluble powders which means that they can be difficult to process. Here we report a new class of solvent-dispersible porous polymers synthesised by reversible addition-fragmentation chain transfer mediated polymerisation-induced self-assembly (RAFT-mediated PISA), formed from a PEG macro-CTA polymerised with divinylbenzene and fumaronitrile. The particles have a dual morphology consisting of smaller spheres of 24-29 nm aggregated into larger particles of 204 - 262 nm. Gas sorption analysis showed the particles to have BET surface areas of 274 to 409 m2/g with internal pore sizes centred around 1.8 nm and further larger pores arising from the sphere packing of the aggregates. The particles were found to be photoluminescent (emission λmax = 326 nm) when exposed to UV light which could be quenched by the addition of nitroaromatic compounds. For example, 99% if the emission was quenched in the presence of 38 ppm of picric acid

CO₂ Capture by Porous Hyper-Cross-Linked Aromatic Polymers Synthesized Using Tetrahedral Precursors

Low-cost synthesis of porous hyper-cross-linked aromatic polymers (PHAPs) was achieved via the FeCl₃-catalyzed Friedel–Crafts alkylation reaction between tetraphenylsilane or tetraphenylgermanium as a building block and formaldehyde dimethylacetal as a cross-linker. The synthesized polymers were chemically and thermally stable and exhibited high surface areas of up to 1137 m² g^–1 (PHAP-1) and 1059 m² g^–1 (PHAP-2). The adsorption isotherms of the PHAPs revealed a high CO₂ adsorption capacity (104.3–114.4 mg g^–1) with an isosteric heat of adsorption in the range 26.5–27.3 kJ mol^–1 and a moderate CH₄ adsorption capacity (12.6–13.8 mg g^–1) at 273 K and 1 bar. The PHAP networks also exhibited high CO₂/N₂ and CO₂/CH₄ relativities of 29.3–34.2 and 11.3–12.5, respectively, at 273 K