25 research outputs found
Catalytic Activation of small molecules with metal complexes : CO2 and O2
Catalytic transformation of carbon dioxide into useful organic compounds has attracted much attention due to its economic and environmental benefits. In addition, other reasons are also taken into account, such as the possible utilization of CO2 as a renewable source chemical and the growing concern of the greenhouse effect. CO2 is an abundant, cheap, and safe C1 building block in organic synthesis. However, due to the inert nature of CO2, efficient catalytic processes of its chemical fixation remain a significant challenge. In this work, we have studied a possible pathway for practical utilization of CO2. The reaction of CO2 with epoxides giving cyclic carbonates, has been investigated. New catalyst systems based on cobalt capable of catalyzing the chemical transformation of carbon dioxide are described in detail.
Oxygen is a cheap, readily available and environmentally friendly natural oxidant. The catalytic activation of molecular oxygen has great potential in a variety of applications. Catalysis and reactions, which are based on molecular oxygen, can also be considered to be ecologically benign processes. Moreover, catalytic reactions in water are highly desirable in terms of green chemistry. In this context, our purpose was to develop an environmentally friendly catalytic systems, suitable for oxidation of alcohols with molecular oxygen in water solution. In this part of the work, efficient catalysts, based on copper complexes have been synthesized and studied in the presence of TEMPO for the oxidation of benzyl and aliphatic alcohols with molecular oxygen in aqueous and nonaqueous medium
Synthesis and Characterization of α,ω-disubstituted Quaterthiophenes Functionalised with Polar Groups for Solution Processed OTFTs
Synthesis and characterization of α,ω-disubstituted quaterthiophenes functionalised with polar groups for solution processed OTFTs
A series of soluble quaterthiophenes (4Ta–g) bearing ester groups in the a,u-terminal positions separated
from the quaterthiophene core by ethylene (4Ta–c), vinylene (4Td–f) or ethynylene (4Tg) spacers
was synthesized by means of a Pd-catalyzed homocoupling of bithiophenes proceeding via C–H bond
activation. The synthetic approach gave satisfying yields of 4Ta–f but resulted in only 3% yield of 4Tg due
to the competitive hydrofluorination of the triple bond. The quaterthiophenes 4Ta–g were characterized
by NMR, FTIR, UV–vis, PL spectroscopies, HRMS, TGA and CV. Thin-films of 4Ta–g were deposited either
by spin-coating or by thermal evaporation on Si/SiO2 for the fabrication of top-contact OTFTs. The devices
prepared using 4Ta–c bearing the ester functional group separated from the quaterthiophene core
by an ethylene spacer showed average hole field-effect mobility up to 2.7103 cm2 V1 s1 and up to
6103 cm2 V1 s1 for solution processed and for thermally evaporated OTFTs, respectively. The
remarkably high solubility of 4Ta–c, along with their respectable performances in OTFTs render these
molecules promising for practical applications as active layers in chemically-sensitive devices