sp2 Carbon Stable Radicals

Abstract

sp2 Nanocarbons such as fullerenes, carbon nanotubes, and graphene molecules are not only open-shell species, but spatially extended, due to which their chemistry is quite specific. Cogently revealed dependence of the final products composition on size and shape of the carbons in use as well as on the chemical prehistory is accumulated in a particular property—the stabilization of the species’ radical efficiency, thus providing the matter of stable radicals. If the feature is highly restricted and rarely available in ordinary chemistry, in the case of sp2 nanocarbons it is just an ordinary event providing, say, tons-in-mass stable radicals when either producing such widely used technological products as carbon black or dealing with deposits of natural sp2 carbons such as anthracite, shungite carbon, and other. Suggested in the paper is the consideration of stable radicals of sp2 nanocarbons from the standpoint of spin-delocalized topochemistry. Characterized in terms of the total and atomically partitioned number of effectively unpaired electrons as well as of the distribution of the latter over carbon atoms and described by selectively determined barriers of different reactions exhibiting topological essence of intermolecular interaction, sp2 nanocarbons reveal a peculiar topokinetics that lays the foundation of the stability of their radical properties.

Virtual Vibrational Spectrometry of Stable Radicals—Necklaced Graphene Molecules

“…Bare nanosized honeycomb sheets (graphene domains below), surrounded with heteroatom necklaces of different chemical composition, were selected for the current study. These molecules are radicals [13], among which bare graphene domains are the strongest. The latter do not exist either in nature or in a laboratory, which does not prevent them from being favorite objects in virtual graphenics [14].…”

“…In this case, the effect is not connected with hydrogen atoms directly, but results from the influence of the hydrogen presence on the configuration of the sp 2 C=C bonds. The latter is quite remarkable and is obviously caused by a particular delocalization of the electron and spin density over the carbon atoms of any honeycomb structure (see [13,26] and references therein). As seen, the presence of hydrogen significantly influences Raman spectrum I of the reference (5, 5) domain , starting form one atom in the DT necklace (spectrum VI).…”

“…1 Radicalization of the studied molecules is characterized by the number of effectively unpaired electrons N D and spin contamination ∆ Ŝ2U[13] 2. …”

Virtual Vibrational Analytics of Reduced Graphene Oxide

“…All of the calculations discussed in the current paper were performed using the AM1 version of the code in the UHF approximation since all of the studied DTs are open-shell molecules [13,18]. It should be noted that such an approach, similar in essence, but less categorically formulated, was practically realized by Yamada's team previously by applying to both rGO and graphene oxide (GO) [19]. In the framework of the main algorithm of the modern VVS above-mentioned and applying it to the specification, related to different computational tools and suggested previously [12], this approach might be considered as an virtual experiment performed using a DFT Spectrodyn device.…”

“…1 Greek symbols  and  mark the molecule bending and stretching, respectively; 2 Equilibrated structures, AM1 UHF calculations; 3 Reference is taken from [20]; frequency regions are given in the experimental spectra scale; 4 Out-of-plane deformations; 5 In plane deformations; 6 Collective vibrations of the graphene domain atoms [21]. 1 Blod GFKs correspond to the most intense bands; 2 Equilibrated structures, AM1 UHF calculations; 3 Authors' suggestions on the basis of original studies [19,[22][23][24]; frequency regions are given in the experimental spectra scale; 4 Out-of-plane deformations; 5 In plane deformations.…”