The Diels-Alder Cycloaddition Reaction of Substituted Hemifullerenes with 1,3-Butadiene: Effect of Electron-Donating and Electron-Withdrawing Substituents

Abstract

Abstract:The Diels-Alder (DA) reaction provides an attractive route to increase the number of six member rings in substituted Polycyclic Aromatic Hydrocarbons (PAHs). The density functional theory (DFT) B3LYP method has been used in this work to inquire if the substitution of H over the edge of triindenetriphenylene (pristine hemifullerene 1) and pentacyclopentacorannulene (pristine hemifullerene 2), could improve the DA cycloaddition reaction with 1,3-butadiene. The substituents tested include electron-donating (NH2, OMe, OH, Me, i-Pr) and electron-withdrawing groups (F, COOH, CF3, CHO, CN, NO2). The electronic, kinetic and thermodynamic parameters of the DA reactions of the substituted hemifullerenes with 1,3-butadiene have been analyzed. The most promising results were obtained for the NO2 substituent; the activation energy barriers for reactions using this substituent were lower than the barriers for the pristine hemifullerenes. This leads us to expect that the cycloadditions to a starting fullerene fragment will be possible.

Dimerization of pentacyclopentacorannulene C30H10 as a strategy to produce C60H20 as a precursor for C60

“…Our previous studies of the substituent effect in the reactivity of C 30 H 10 suggested that it is possible to increase its reactivity in the DA reactions. 31,32 The results presented support the possibility to dimerize C 30 H 10 and the existence of C 60 H 20 . In fact, the fullerene hydride C 60 H 20 has been detected in the mass spectra of C 60 hydrides synthesized by condensation of benzene molecules, 49 although, the structure of C 60 H 20 formed in these experiments is not necessarily the belt-like structure discussed here, which is closely connected to the structure of the precursor C 30 H 10 .…”

“…30 Although the full C 30 H 10 (1) has not been synthesized yet, one can expect that similar methods will allow for the synthesis of this fragment. On the basis of ab initio calculations Mojica et al 31,32 suggested that C 30 H 10 (1) is a good dienophile towards DA cycloaddition reaction with butadiene and possesses high symmetry, which makes it an ideal fragment to produce C 60 H 20 and the C 60 fullerene (Fig. 1).…”

Small Molecular Weight Aldose (d-Glucose) and Basic Amino Acids (l-Lysine, l-Arginine) Increase the Occurrence of PAHs in Grilled Pork Sausages

“…The definite mechanism for the formation of PAHs is not well understood. Some researchers proposed that they might be formed through free radical reactions, intramolecular addition or the polymerization of small molecules [5,6,7]. In meat products, PAHs are formed during processing at a high temperature, such as by smoking, drying, roasting, and grilling [8,9,10].…”

Quantum‐chemical approaches in the study of fullerene and its derivatives by the example of the most typical cycloaddition reactions: A review

“…In this particular case, the F I G U R E 3 Dimerization reactions between two [1+1] type moieties and between two [2+2] type moieties [122] activation barriers are lower than for the other reactions; what is more, the free energies of the process are negative, in contrast to the positive values for the other processes. Later, the same authors [124] used the B3LYP functional to find out whether the Diels-Alder cycloaddition with 1,3-butadiene can be accelerated by replacement of H at the border of triindenetriphenilene (primary hemifulleren 1) and pentacyclopentacorannulene (primary hemifulleren 2). The tested substituents included electron-donating groups (NH 2 , OMe, OH, Me, i-Pr) and electron-withdrawing ones (F, COOH, CF 3 , CHO, CN, NO 2 ).…”