Carlo Fragale

Reaction of silylalkylmono- and silylalkyldi-amines with carbon dioxide: evidence of formation of inter- and intra-molecular ammonium carbamates and their conversion into organic carbamates of industrial interest under carbon dioxide catalysis

The reactivity of industrially relevant silylalkylamines towards CO2 and dialkyl/arylcarbonates is discussed. The kinetics of uptake of carbon dioxide at various temperatures shows that at 295 K, silylalkylmonoamines react with carbon dioxide in a 2∶1 molar ratio, affording classic intermolecular ammonium carbamates of formula RNHCOO−+NH3R, while at 273 K, dimeric carbammic acids, (RNHCOOH)2, are formed. Conversely, silylalkyldiamines react at 297 K with carbon dioxide to afford zwitterionic intramolecular six-membered cyclic ammonium carbamates of formula RNH2+CH2CH2NHCOO−, a unique example of CO2 uptake by an amine with a 1∶1 molar ratio. Such systems may have a potential application in CO2 separation. The catalytic role of carbon dioxide in the carbamation of the above mentioned amines by reaction with organic carbonates is described.

Bioinorganic chemistry of nickel and carbon dioxide: an Ni complex behaving as a model system for carbon monoxide dehydrogenase enzyme

Abstract In this paper we report the results of our studies on Ni complexes, the chemistry of which is relevant to the carbon monoxide dehydrogenase (CODH) enzyme of acetogenic bacteria. A single Ni system is able to promote both the reduction of carbon dioxide to carbon monoxide and the subsequent coupling of bound CO with an oletin and a thio group to afford an organic thioester, mimicking the enzyme activity.

Carbon dioxide as modulator of the oxidative properties of dioxygen in the presence of transition metal systems

In the presence of transition metal (Fe, Rh) catalysts, CO2 can modulate the oxidative properties of O2 towards tetrahydrofuran (THF) and styrene; the intermediate formation of metal-peroxocarbonate species, [Ln[graphic omitted]], seems to play a key role in these processes.

Charge transfer complexes of hexamethylphosphoramide chalcogenides

Abstract Charge transfer complexes between iodine and hexamethylphosphoramide chalcogenides have been investigated spectrophotometrically. The equilibrium constant increases on passing from O to Se but not proportionally to the ionization potential of the atoms. A linear correlation was found between ΔG (or ΔS ) and ΔH . The structure of the complexes is discussed.