Ricerc@Sapienza

The oxidation of a series of alkylaromatic compounds with H2O2 catalyzed by an imine-based non-heme iron complex prepared in situ by reaction of 2-picolylaldehyde, 2-picolylamine, and Fe(OTf)2 in a 2 : 2 : 1 ratio leads to a marked chemoselectivity for aromatic ring hydroxylation over side-chain oxidation. This selectivity is herein investigated in detail. Side-chain/ring oxygenated product ratio was found to increase upon decreasing the bond dissociation energy (BDE) of the benzylic C-H bond in line with expectation.

The oxidation of a series of N-acetyl amino acid methyl esters with H2O2catalyzed by a very simple iminopyridine iron(ii) complex 1 easily obtainable in situ by self-assembly of 2-picolylaldehyde, 2-picolylamine, and Fe(OTf)2was investigated. Oxidation of protected aliphatic amino acids occurs at the α-C-H bond exclusively (N-AcAlaOMe) or in competition with the side-chain functionalization (N-AcValOMe and N-AcLeuOMe). N-AcProOMe is smoothly and cleanly oxidized with high regioselectivity affording exclusively C-5 oxidation products.

A kinetic study of the hydrogen atom transfer (HAT)reaction from a series of N-Boc- or N-Acetyl-protected amino acids to the phthalimide N-oxyl radical (PINO)was carried out to obtain information about reactivity and selectivity patterns. With amino acids containing aliphatic side chains, the 2nd order rate constants are of the same order of magnitude, in agreement with a HAT process involving the Cα−H bond. Proline is the most reactive substrate suggesting that HAT process involves the Cδ−H bond instead of Cα−H bond.

The upgrading of complex bio-renewable feedstock, such as lignocellulose, through depolymerisation benefits from the selective reactions at key functional groups. Applying homogeneous catalysts developed for selective organic oxidative transformations to complex feedstock such as lignin is challenged by the presence of interfering components. The selection of appropriate model compounds is essential in applying new catalytic systems and identifying such interferences.

Predictability is a key requirement to encompass late-stage C-H functionalization in synthetic routes. However, prediction (and control) of reaction selectivity is usually challenging, especially for complex substrate structures and elusive transformations such as remote C(sp3 )-H oxidation, as it requires distinguishing a specific C-H bond from many others with similar reactivity.

Gas phase ion chemistry has fundamental and applicative purposes since it allows the study of the chemical processes in a solvent free environment and represents models for reactions occurring in the space at low and high temperatures. In this work the ion-molecule reaction of sulfur dioxide ion SO.+2 with carbon monoxide CO is investigated in a joint experimental and theoretical study.

The oxidation of a series of aryl 1-methyl-1-phenylethyl sulfides with H2O2catalyzed by the two tetradentate nonheme-iron complexes [(PDP)FeII(SbF6)2] and [(BPMCN)FeII(OTf)2] occurs by an electron transfer-oxygen transfer (ET/OT) mechanism as supported by the observation of products deriving from fragmentation of the corresponding radical cations in association with S-oxidation products (sulfoxides). © 2017 Taylor & Francis Group, LLC.

The aim of this work was to investigate the aggregation of metallic iron nanoparticles in a Rushton equipped agitated vessel open at the atmosphere. The particles were synthetized using oxygen-free reagent solutions and subsequently were suspended in water in an open lab-scale agitated vessel. The particle size distribution, zeta-potential, pH and Fe(0) content were monitored over the time, up to the complete oxidation of the particles.