Biomedical subjects

Sandro Campestrini

Publications and source records attributed to Sandro Campestrini.

7 recordsLinked to original sources

PubMed2006

Turn and helical peptide spacers: combined distance and angular dependencies in the exciton-coupled circular dichroism of intramolecularly interacting bis-porphyrins.

In a previous study we examined by the exciton-coupled circular dichroic method the distance effect generated by three-rigid-turn and helical-peptide spacers. In this connection porphyrins were confirmed to be excellent reporter chromophores. In the present investigation we have completed this research by expanding the original analysis to the assessment of the combined role of the chromophore distance and orientation with use of the same porphyrin derivatives and additional four analogous spacers of different main-chain lengths. We find that not only the intramolecular separation of the chromophores, but the angular dependence between the directions of their effective transition moments as well, are responsible for the onset and modulation of the intensity of the exciton-coupling phenomenon of the porphyrin Soret band.

Circular Dichroism↗

PubMed2006

Aerobic oxidation of alcohols in carbon dioxide with silica-supported ionic liquids doped with perruthenate.

The replacement of toxic Cr(VI) for O2 and of chlorinated solvents for supercritical carbon dioxide (or ionic liquids) in the oxidation of alcohols remains hindered by the low selectivity and activity of the current heterogeneous catalysts. Using an integrated approach that combines sol-gel entrapped perruthenate as aerobic catalyst, an encapsulated ionic liquid as solubility promoter, and scCO2 as the reaction solvent, we have developed a system capable of rapidly converting different alcohols into carbonyl compounds with complete selectivity, including substrates which are otherwise difficult to oxidise. The methodology is generally applicable and may easily be extended to other waste-free, catalytic syntheses of fine chemicals.

Aerobiosis↗

PubMed2006

FluoRuGel: a versatile catalyst for aerobic alcohol oxidation in supercritical carbon dioxide.

FluoRuGel--a hybrid fluorinated silica glass doped with TPAP (tetra-n-propylammonium perruthenate)--is a versatile catalyst for the aerobic oxidation of different alcohols in dense phase CO(2) with marked stabilization and activity enhancement of perruthenate upon its confinement in the sol-gel fluorinated silica matrix. A brief competitive analysis shows large potential rewards.

Journal Article↗

PubMed2006

Better chemistry through ceramics: the physical bases of the outstanding chemistry of ORMOSIL.

Twenty years after their invention, sol-gel organically modified silicates (ORMOSIL) are finding a number of impressive applications that range from efficient deliver of genes into mouse brains to self-ordered helices of interest to fields as diverse as optics, catalysis, molecular recognition, and chromatography. The physical bases of this mulifaceted chemistry, therefore, are of immense importance to scientists working toward new applications such as photovoltaics and catalysis that are crucially important in making sustainable global development. The purpose of this article is to provide a general picture of ORMOSIL's physical chemistry that will be useful in the creative development of new materials capable to solve a number of relevant open problems.

Journal Article↗

PubMed2005

Ru-based oxidation catalysis.

Ranging from the oxidative conversion of water to O(2) to the elegant hydroxylation of olefins and to oxidative dehydrogenation of alcohols Ru-mediated oxidations are finding increasing application due to the unique properties of this extremely versatile transition metal, whose oxidation state can vary from -II to +VIII. Covering recent developments in both homogeneously and heterogeneously catalysed oxidations (in liquid-phase as well as in novel reaction media), this tutorial review aims to provide investigators with a general picture of the chemical and structural origins of the excellent performance of many ruthenium catalysts and to promote further advancement that, it is envisaged, will soon benefit society at large.

Alcohols↗

PubMed2003

Distance dependency of exciton coupled circular dichroism using turn and helical peptide spacers.

Porphyrins are promising chromophores for the investigation of the still unexplored area of 3-dimensional structural studies of proteins by using the exciton coupled circular dichroism (CD) method. The synthesis, conformational characterization by FTIR absorption and (1)H-NMR, and CD properties are described for a model bis-porphyrin system based on homooligo-[L-(alphaMe)Val](n) peptides as rigid spacers. In particular, the coupled CD phenomenon is experimentally detected, the intensity of which is modulated by the interchromophoric distance. These results extend and integrate those already reported with steroid, dimeric steroid, and brevetoxin bridges.

Circular Dichroism↗

PubMed2002

Highly chemoselective hydrogenation of 2-ethylanthraquinone to 2-ethylanthrahydroquinone catalyzed by palladium metal dispersed inside highly lipophilic functional resins.

Most hydrogen peroxide is currently produced by the selective hydrogenation of 2-ethylanthraquinone (EAQ) to 2-ethylanthrahydroquinone (EAHQ), followed by treatment with dioxygen; this produces hydrogen peroxide and regenerates 2-ethylanthraquinone. We have developed novel catalysts for this process that are based on palladium supported on very lipophilic functional resins and that are able to promote a chemoselectivity for EAHQ slightly but definitely superior to that provided by an industrial catalyst under identical conditions. This finding demonstrates the potential of variations of the lipophilic/hydrophilic character of the support as a tool for the improvement of the chemoselectivity of resin-based metal catalysts.

Journal Article↗