Functionalization of silica through thiol-yne radical chemistry: a catalytic system based on gold nanoparticles supported on amino-sulfide-branched silica

Abstract

Synthesis of a novel catalytic system based on gold nanoparticles supported on silica functionalized via a thiol-yne radical reaction.

Encapsulation of Metal Nanoparticles within Metal–Organic Frameworks for the Reduction of Nitro Compounds

“…Au NPs supported on the ethynyl-based MOF by electrostatic interaction resulted in being a stable and reusable catalyst to perform the reduction of 4-nitrophenol or 2,4-dinitrophenol to their corresponding amino derivatives by using NaBH 4 in aqueous media. The activity of this catalyst for the 4-nitrophenol reduction by NaBH 4 was more than one order of magnitude (rate constant 6.64 × 10 −2 s −1 ) greater or comparable than analogous Au catalysts supported on Nano ActiveTM Mg [59], meso-HAP (HAP: hydroxyapatite) [73], PAMAM G3 (PAMAM G3: 3 rd generation poly(amidoamine)) [74], SiO 2 [75], SiO 2 @Yne (Yne: alkynyl carbamate moieties) [76], Au-SiO 2 @AeThio (AeThio: amino-sulfide branches) [77], CeO 2 -NT (NT: nanotubes) [78], PPy-NTs (PPy: polypyrrole) [79], MIL-100(Fe) [80], or hm-ZrO 2 (hm: hollow-mesoporous) [81]. Interestingly, if the reduction of 4-nitrophenol takes place using ethanol as solvent the resulting product was its azo derivative.…”

Structure, morphology and magnetic properties of Au/Fe3O4 nanocomposites fabricated by a soft aqueous route

“…Up to date, to the best of our knowledge, Au/Fe 3 O 4 systems are typically prepared either by mixing the magnetite with pre-formed AuNP [23] , or by the chemical or physical reduction of an Au(III) precursor in the presence of Fe 3 O 4 [24][25] [26] [27]. To this regard, our research group has successfully developed a convenient method for the anchoring of AuNP on nanosilica matrices modified with a propynylcarbamate organic functionality, without the need of any additional reducing and/or stabilizing agents [28] [29]. Such a synthetic methodology has been extended to the preparation of AuNP supported on commercial micrometer-sized oxides, including SiO 2 , Al 2 O 3 and TiO 2 [21].…”

A Combined Mechanochemical and Calcination Route to Mixed Cobalt Oxides for the Selective Catalytic Reduction of Nitrophenols

“…We observe a similar enhanced absorbance at 310 nm which decreases as 4NP is consumed ( Figure 6B and Figure S7). Thus, we postulate that increased concentration of K + in the system, studied herein, could promote a complementary reaction pathway via 4-nitrosophenol, thus, accounting for the increased absorbance, and slight reduction in k app (δ − 0.057 min −1 ) [112][113][114][115]. Overall, it is evident that trace KOH is not the driving factor in the catalytic activity reported herein but could enhance a complementary or concurrent reaction pathway, ultimately leading to the same product.…”