Inert free radicals (IFR): a unique trivalent carbon species

Abstract

Perchloro-organic compounds can be viewed as constituting a chemical domain analogous to that of conventional organic chemistry. To each compound belonging to the latter-and containing at least one hydrogen atom-there can be imagined a corresponding related member belonging to the former as a result of replacing all hydrogens by chlorine atoms (perchlorination).The initiation of this "perchloro-organic" chemistry can be ascribed to the pioneering syntheses, by Faraday and Julin in 1821, of hexachloroethane, tetrachloroethylene, and hexachlorobenzene.1 The field then remained almost dormant for nearly 140 years in spite of numerous

Valence Tautomerism: New Challenges for Electroactive Ligands

“…[69] Moreover, the cyclic voltammetry of perchlorotriphenylmethyl radicals shows the formation of two different stable ionic species that correspond to the oxidation and reduction of this radical (see Scheme 6). This allows the corresponding anions and cations to be obtained, either chemically or electrochemically, both in solution and in solid state, which also show considerable stabilities in accordance with the steric shielding of their central carbon atoms.…”

Structural and Magnetic Modulation of a Purely Organic Open Framework by Selective Guest Inclusion

“…The advantages of this PTM family of radicals are manifold: 1) These bulky radicals are sterically hindered due to the presence of several chlorine atoms, which renders them thermally and chemically stable, but also prevents close packing and interpenetration within the final structure; [28] 2) carboxylic-PTM radicals are open-shell species capable of transmitting and increasing magnetic interactions through the structure, as previously shown for PTMMC, [29] which formed hydrogen-bonded R 2 2 (8) dimers that promoted the transmission of a weak ferromagnetic interaction; and 3) carboxyl-substituted PTM radicals can be considered as an expanded version of trimesic acid, in which the benzene-1,3,5-triyl units have been replaced by an sp 2 -hybridized Scheme 1. Idealistic schematic representation of the solvatomagnetic behavior of a porous solid induced by the dynamic structural flexibility of its open framework.…”

Polychlorotriphenylmethyl Radicals: Towards Multifunctional Molecular Materials

“…The thermally activated IET was also studied by variable temperature EPR for radical anions 15 −• and 16 −• . Thus, the EPR spectrum of 15 −• at 200 K displays two symmetrical lines arising from the hyperfine coupling of the unpaired electron with one hydrogen atom of the ethylene moiety and the resulting1 H hyperfine coupling constant is very close to that of related monoradicals. This result clearly demonstrates that at this temperature the unpaired electron of radical anion 15 −• 20 Experimental (left) and simulated (right) EPR spectra of 15 −• at different temperatures in dichloromethane.…”