Angelo Alberti

Poly(glycidyl methacrylate): a highly versatile polymeric building block for post-polymerization modifications

The treatment of poly(glycidyl methacrylate) with nucleophilic agents yielded new linear homo/co-polymers. The materials obtained have different physicochemical properties depending upon the nucleophiles utilized and thus, by this way, water soluble polymers are easily accessible. This approach is also very convenient for the synthesis of amphiphilic block copolymers. Additional chemical modifications can further transform the obtained polymers after the post-polymerization treatment. Starting from RAFT pre-synthesized/pre-functionalized polymers, the described procedures allow us to obtain a wide variety of chemically diverse materials characterized by controlled structure and specific functions.

Addition of organometallic radicals to organic substrates. Reaction between manganese decacarbonyl and α-dicarbonyl compounds

Abstract Some o -quinones and 1,2-diketones were allowed to react with manganese pentacarbonyl radicals generated in situ and the resulting persistent paramagnetic adducts studied by ESR spectroscopy. The evolution of carbon monoxide during the reaction together with the symmetrical distribution of the spin density in the organic framework (as implied by the spectral data) indicated chelation of a Mn(CO) 4 moiety by the two oxygens of the dicarbonyl substrates. One or more carbon monoxide groups can be replaced by compounds containing nitrogen, phosphorus, arsenic or antimony as binding sites. A conjugative transfer of spin density is proposed for the last three classes of substituents, while a σ mechanism is probably involved in the case of nitrogen-containing ligands.

Dynamic migration of organometallic groups in free radical adducts of benzil

Abstract Adducts formed by silyl and germyl radicals with benzil exhibit alternating line-width effects in their ESR spectra which we attribute to migration of the organometallic moiety between the two carbonyl groups.

Paramagnetic adducts between manganese-centred radicals and nitro derivatives. A new class of manganese-containing radicals

Abstract The photolytic or thermal reaction of pentacarbonylmanganese radicals with either aromatic or aliphatic nitro compounds in the presence of PBu 3 , and in one case of pyridine, gives spin adducts which have been studied by ESR spectroscopy. On the basis of the spectral parameters these paramagnetic species, which represent the first example of a new class of transition metal-containing radicals, have been assigned a cyclic structure, with the manganese atom acting as a bridge between the two oxygens of the nitro group; this implies the loss of a CO unit during complexation. The role of the phosphine in stabilizing these radicals by replacing one or two CO moieties is critical; doubly-substituted species are much more persistent than their mono-substituted analogues. In the absence of PBu 3 the corresponding paramagnetic adduct could be observed only with 2-methyl-2-nitropropane.

3,5-Di-tert-butylthiobenzoyltriphenylsilane: A versatile spin trapping agent

Abstract 3,5-Di-tert-butylthiobenzoyltriphenylsilane (DBTBTPS) has been synthesized and tested as a spin trapping agent for electron spin resonance studies. Upon reaction with a variety of radicals of different nature inside the cavity of the ESR spectrometer, DBTBTPS leads to the observation of rather persistent spectra which in nearly all cases allow the unambiguous identification of the trapped species. DBTBTPS is somewhat less stable than thiobenzoyltriphenylsilane (TBTPS), the unsubstituted thiobenzoyltriphenylsilane; yet, as it affords spin adducts whose spectra are characterized by a smaller number of lines, it may prove more useful than TBTPS itself when dealing with radicals leading to species with a large number of magnetically active nuclei interacting with the unpaired electron.

An esr investigation on group IVb organometalloxy- and organometalthio-pyryl and thiapyryl radicals

Abstract The spin adducts of triphenylsilyl, triphenylgermyl and triphenylstannyl radicals with γ-pyrone, γ-thiopyrone, thia-γ-pyrone and thia-γ-thiopyrone have been studied by ESR spectroscopy. The spectral parameters indicate that these radicals adopt the conformation where the O-M or S-M bonds are eclipsed with the 2 p z orbital of the γ-carbon, despite the absence of hindering substituent groups in proximity of the radical centre. The electronic effects of sulphur and oxygen on the spin density distribution are also discussed.

Regioselective addition reactions of group IVB organometallic radicals with p-diones. An ESR study

Abstract The group IVB organometallic radical adducts of a number of substituted p -diones and related compounds have been investigated by ESR spectroscopy. In the case of substrates with unequivalent carbonyl groups two distinct isomeric adducts have been detected, and the factors affecting the regioselectivity of the addition reaction are discussed. The magnitude of the hyperfine splitting constants at the metal atoms and the trend of the g -values are consistent with a conformation for the adducts where the organometallic substituent eclipses the p π orbital on the radical centre.

Adducts of silyl, germyl and stannyl radicals with heterocyclic α-diketones: an electron spin resonance investigation

Hyperfine coupling constants are reported for adducts of silyl, germyl and stannyl radicals with a series of substituted benzo [b]thiophen-2,3-diones (Ia—Ip), benzo [b] furan-2,3-dione (II), ninhydrin (III), and thieno [ 3,2-b] thiophen-2,3-dione (IV). The conformational and electronic properties of these radicals are compared with those of similar adducts formed by diaryl ketones.

An ESR study of some Group IVB radical adducts with aromatic ketones

Abstract Hyperfine coupling constants are reported for the paramagnetic adducts of silyl, germyl and stannyl radicals with five aromatic ketones. The spin distribution in these systems is compared with the H atom adducts and analogous hydrocarbon radicals. The large 117Sn and 119Sn satellite splittings observed in the stannyl adducts indicate that these radicals exist in a conformation with the O  Sn bond orthogonal to the π-system. The ESR spectrum of the previously unknown anthronyl radical has been recorded and analysed.

Oxidative stress, d-ROMs test, and ceruloplasmin

ABSTRACT Human serum samples were evaluated for oxidative stress with the d-ROMs test. The ceruloplasmin (CP) and copper contents of the samples was independently measured and compared to those calculated on the basis of the d-ROMs test results for pure CP solutions. The d-ROMs readings did not show any significant correlation with either the CP or copper contents of the samples. Critical interference of CP on the d-ROMs test was therefore excluded and the usefulness of the test in the evaluation of global oxidative status of a biological sample could be reassessed.