[2+2]-cycloadditions of alkenes with the triphenylallenyl cation

The triphenylallenyl cation (8), generated from triphenylpropynol (7) and FSO3H, reacts with alkenes to give the allyl cations 12, which may be deprotonated to yield the methyleneccylobutenes 14. Alternatively, 12 can be converted into the 2-vinyl-indenes 13 two subsequent electrocyclic reactions

Electrochemical intercalation and electrical conductivity of graphite fibers

Lamellar compounds of graphite fibers were prepared by electrochemical intercalation. The dependence of the electrical resistance on the intercalate concentration was determined by a quasi simultaneous method. A factor 30 decrease of the relative fiber resistance was obtained with fluorosulfuric acid

Method for separating single-wall carbon nanotubes and compositions thereof

The invention relates to a process for sorting and separating a mixture of (n, m) type single-wall carbon nanotubes according to (n, m) type. A mixture of (n, m) type single-wall carbon nanotubes is suspended such that the single-wall carbon nanotubes are individually dispersed. The nanotube suspension can be done in a surfactant-water solution and the surfactant surrounding the nanotubes keeps the nanotube isolated and from aggregating with other nanotubes. The nanotube suspension is acidified to protonate a fraction of the nanotubes. An electric field is applied and the protonated nanotubes migrate in the electric fields at different rates dependent on their (n, m) type. Fractions of nanotubes are collected at different fractionation times. The process of protonation, applying an electric field, and fractionation is repeated at increasingly higher pH to separated the (n, m) nanotube mixture into individual (n, m) nanotube fractions. The separation enables new electronic devices requiring selected (n, m) nanotube types

Alkaline-earth (Be, Mg and Ca) bonds at the origin of huge acidity enhancements

The interaction between alkaline-earth derivatives with the general formula X2M (X = H, F and Cl; M = Be, Mg and Ca) and a set of Lewis bases, including first and second-row hydrides, namely YHn(Y = O, N, F, S, P and Cl) hydrides, as well as other typical cyclic organic bases, such as aniline, 1H-1,2,3-triazole, 1H-tetrazole and phenylphosphine, was investigated using the G4 ab initio composite method. Contrary to what was expected, it was found that the interactions involving Mg and Ca derivatives were not necessarily weaker than those between beryllium bonds. The origin is two-fold: larger deformation of the interacting systems when Be-derivatives are involved and appearance of secondary non-covalent interactions in the formation of some of the Mg- and Ca-containing complexes. Hence, the dissociation of the latter complexes may require higher enthalpies than that of the Be complexes. These deformations are triggered by a significant redistribution of electron density of the two interacting moieties, which also result in dramatic changes in the reactivity of the interacting compounds and in particular in the intrinsic basicity of the Lewis bases investigated, to the point that conventional bases, such as ammonia or aniline, upon complexation with MCl2(M = Be, Mg and Ca), become stronger Brønsted acids than phosphoric acid, whereas other bases, such as 1H-tetrazole, become stronger acids than perchloric acid.This work was carried out with financial support from the Ministerio de Economía, Industria y Competitividad (projects CTQ2015-63997-C2 and CTQ2013-43698-P), by the COST Action CM1204 and Comunidad Autónoma de Madrid (S2013/MIT2841, Fotocarbon

Structures of Protonated Methyl Phenols in Antimony Pentafluoride-Fluorosulfuric Acid at - 60 °C

The site of protonation of a series of methyl substituted phenols in 11.5 mole \u27°/o SbF5 in HS03F was determined using NMR spectrometry. Some substituent effects are explicable without invoking specific salvation. Protonation para to the hydroxy group was favored, but was blocked completely in all but one case by .a p-alkyl group. In para substituted phenols, ortho protonation predominated. Both oxygen and ring protonation were observed for the p-cresol

Oxo and Oxyfluoro Complexes of Iodine (V) and (VII)

The behaviour of potassium iodate, iodic acid and various other iodine V compounds as solutes in fluorosulfuric acid has been studied using cryoscopy, conductivity, Raman and nmr spectroscopy. Evidence has been obtained for the species IOF₂SO₃F as the major product of the reactions, and this species has been shown by Raman spectroscopy to be fluorosulfate bridged. The IO₂⁺ and IOF₂⁺ cations have been prepared from the corresponding oxyfluorides and a strong fluoride ion acceptor and characterized for the first time. The structure of IO₂F₃ has been the subject of several publications and although they all agree that the molecule is polymeric, no definite conclusion on the polymer size had been reached. It has been shown in this work, that IO₂F₃ is a cis oxygen bridged trimer in the solid, liquid and solution phases. The chemistry of IO₂F₃ with strong Lewis acids was studied and it was found to be a fluoride ion acceptor forming polymeric complexes of the type (IO₂F₄ MF₄)n. The previously unknown salt KIO₂F₄ was prepared and characterized and it was found to exist as the trans isomer in the solid and in acetonitrile solution but as a mixture of cis and trans in solvents where fluoride ion transfer can occur. IOF₅ has previously been shown not to be a fluoride ion donor but the ¹⁹F nmr and Raman spectrum of solutions containing IOF₅ and SbF₅ indicated an interaction between IOF₅ and the Lewis acid through the oxygen. At low temperature in SO₂F₂ as a solvent, 1:1 and 1:2 complexes were observed. An attempt to prepare periodyl fluoride IO₃F, the last of the series of iodine (VII) oxyfluorides proved unsuccessful.Doctor of Philosophy (PhD