Search results for "cross coupling"
showing 9 items of 9 documents
Hybrid ferrocene ligands (P, N) : synthesis, coordination to metals and applications in arylation coupling catalysis
2017
The research theme developed during this thesis concerns the development of new hybrid ferrocene hybrid (P, N) ligands with controlled conformation, robust and stable to air. These hybrid tetradent ligands comprise two types of coordinating functions with distinct steric and electronic properties. Their coordination chemistry with metals such as gold or palladium has been studied and some isolated Au (I) complexes have been used in the arylation coupling catalysis of aryl iodides.
Construction of green nanostructured heterogeneous catalysts via non-covalent surface decoration of multi-walled carbon nanotubes with Pd(II) complex…
2017
Abstract Green nanostructured heterogeneous catalysts were prepared via a bottom-up strategy. Designed ligands were synthesized joining covalently an electrondeficient pyrimidine residue and a scorpiand azamacrocycle. The desired molecular properties were easily transferred to nanostructured materials in two steps: first, exploiting their spontaneous chemisorption onto multi-walled carbon nanotubes (MWCNTs) via the pyrimidinic moiety in water at room temperature, then, taking advantage of the easy coordination of Pd(II) to the azamacrocycle in the same conditions. An evenly distribution of catalytic centres was obtained on the MWCNTs surface. Catalytic properties of these materials were ass…
DEEP EUTECTIC SOLVENTS E LIQUIDI IONICI: SOLVENTI PER LO SVILUPPO DI PROCESSI ECO-COMPATIBILI
2020
L’obiettivo di questi tre anni di Dottorato è stato lo studio e l’utilizzo nuovi solventi di reazione in grado di sostituire i solventi organici classici. In particolare sono stati studiati i Deep Eutectic Solvent (DES) e le miscele di Liquidi Ionici (IL). I DES sono stati utilizzati come solventi per lo studio di reazioni organiche, usate per la formazione di nuovi legami C-C. Nello specifico sono state studiate la reazione di Diels-Alder, e diverse reazioni di coupling C-C catalizzate da Pd. In seguito, i DES sono stati utilizzati per la formazione di nuovi gel supramolecolari, chiamati eutectogel. Questi gel sono stati formati usando come gelator amminoacidi naturali, consentendo quindi …
Isolation of cross-coupling products in model studies on the photochemical modification of proteins by tiaprofenic acid
1999
To gain insight into the chemical nature of drug-induced photoallergy, model studies have been carried out on the photochemical modification of proteins by tiaprofenic acid. Irradiation of decarboxylated tiaprofenic acid (DTPA) in the presence of p-cresol leads to C–C- and C–O-connected p-cresol “dimers”, together with DTPA hydrodimers. The p-cresol–DTPA cross-coupling product was not detected in this reaction. However, a product of this type is formed using a more hindered phenol, such as 2,6-di-tert-butylphenol. Similar results are obtained when tiaprofenic acid (TPA) or its methyl ester are used as photosensitizers. The observed formation of “dimers” can be related to protein photo-cross…
Palladium-Based Metal Organic Frameworks as Heterogeneous Catalysts for C-C Couplings
2022
Among the various cross coupling reactions, C−C cross coupling reaction has attracted many researchers to investigate in the last four decades. The continuous, constant, and consistent progress in this field fetched a Noble prize in 2010, showing the importance of this reaction in diversified fields. Among the various transition metals studied for this reaction, Pd is one of the metals that has exhibited the highest activity due to its unique features and reactivity. Although Pd-based homogeneous catalyst was the preferred choice for many researchers, the field slowly diverted towards the development of Pd-based heterogeneous catalysts for C−C coupling reactions. This is obviously due to th…
Supported C60-IL-PdNPs as extremely active nanocatalysts for C-C cross-coupling reactions
2016
A C60-ionic liquid hybrid has been covalently linked to three different solid supports, namely amorphous silica, SBA-15 and Fe2O3@SiO2, and the resulting materials have been employed as covalently supported ionic liquid phases (cSILP) in order to immobilize and stabilize palladium nanoparticles (PdNPs). These novel hybrid materials are based on a sort of "matryoshka" system (PdNPs@imidazolium-salt@C60@support) in which the imidazolium-based moieties have not been directly linked to the surface of the support, but they are present in an octopus-like spatial arrangement on the uniformly surface-distributed fullerenes. These materials have been fully characterized and successfully employed as …
A New Heterogeneous Catalyst Obtained via Supramolecular Decoration of Graphene with a Pd2+ Azamacrocyclic Complex
2019
A new G-(H2L)-Pd heterogeneous catalyst has been prepared via a self-assembly process consisting in the spontaneous adsorption, in water at room temperature, of a macrocyclic H2L ligand on graphene (G) (G + H2L = G-(H2L)), followed by decoration of the macrocycle with Pd2+ ions (G-(H2L) + Pd2+ = G-(H2L)-Pd) under the same mild conditions. This supramolecular approach is a sustainable (green) procedure that preserves the special characteristics of graphene and furnishes an efficient catalyst for the Cu-free Sonogashira cross coupling reaction between iodobenzene and phenylacetylene. Indeed, G-(H2L)-Pd shows an excellent conversion (90%) of reactants into diphenylacetylene under mild conditio…
Single-Walled Carbon Nanotube–Polyamidoamine Dendrimer Hybrids for Heterogeneous Catalysis
2016
We report the synthesis and catalytic properties of single-walled carbon nanotube-polyamidoamine dendrimers hybrids (SWCNT-PAMAM), prepared via a convergent strategy. The direct reaction of cystamine-based PAMAM dendrimers (generations 2.5 and 3.0) with pristine SWCNTs in refluxing toluene, followed by immobilization and reduction of [PdCl4](2-), led to the formation of highly dispersed small palladium nanoparticles homogeneously confined throughout the nanotube length. One of these functional materials proved to be an efficient catalyst in Suzuki and Heck reactions, able to promote the above processes down to 0.002 mol % showing a turnover number (TON) of 48 000 and a turnover frequency (T…
Unique Reactivity of Fluorinated Molecules with Transition Metals
2014
Organofluorine and organometallic chemistry by themselves constitute two potent areas in organic synthesis. Thus, the combination of both offers many chemical possibilities and represents a powerful tool for the design and development of new synthetic methodologies leading to diverse molecular structures in an efficient manner. Given the importance of the selective introduction of fluorine atoms into organic molecules and the effectiveness of transition metals in C–C and C–heteroatom bond formation, this review represents an interesting read for this aim.