Generation of fullerenyl radicals and chemiluminescence in the (C<Subscript>60</Subscript>—R<Subscript>3</Subscript>Al)—O<Subscript>2</Subscript> system

Fullerenyl radicals (FR) RC₆₀ ^· and chemiluminescence (CL) are generated in the presence of O₂ in C₆₀—R₃Al (R = Et, Buⁱ) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R^· radical, which is an intermediate of R₃Al autooxidation, to C₆₀. Mass spectroscopy and HPLC were used to identify Et_nC₆₀H_m (n, m = 1–6), Et_pC₆₀ (p = 2–6), and dimer EtC₆₀C₆₀Et as stable products of FR transformations. As found by ESR, the EtC₆₀ ^· radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C₆₀— R₃Al)—O₂ system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O₂, which appear as broadening of the ESR signals. Chemiluminescence arising in the (C₆₀—R₃Al)—O₂ system is much brighter (I _max = 1.86·10⁸ photon s⁻¹ mL⁻¹) than the known background CL (I _max = 6.0·10⁶ photon s⁻¹ mL⁻¹) for the autooxidation of R₃Al and is localized in a longer-wavelength spectral region (λ_max = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter ³CH₃CHO* to the products of FR transformation: R_nC₆₀H_m, R_pC₆₀, and EtC₆₀C₆₀Et. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 205–213, February, 2007.     

ESR study of spin-adducts of dialkoxyphosphoryl radicals with di(p-methoxyphenyl)methanofullerene

The addition of phosphoryl radicals to C₆₀C(p-C₆H₄OMe)₂ was shown (ESR) to result in the formation of at least seven isomers differing in their hyperfine coupling constants (HFC) with the phosphorus nuclei and in their kinetic behavior and thermodynamic stability.     

ESR study of spin-adducts of boron-centered carboranyl radicals with fullerene-60 and fullerene-70

Spin-adducts of boron-centered radicals, derivatives ofm-carboran-12, with fullerenes C₆₀ and C₇₀ have been studied by ESR spectroscopy. Constants of hyperfine splitting (HFS) of an unpaired electron with¹⁰B and¹¹B nuclei have been determined from the ESR spectra of C₆₀-B₁₀H₉C₂H₂ radicals. Three isomeric spin-adducts were detected with different HFS constants with¹¹B, andg-factors were detected in the reaction of B₁₀H₉C₂H₂ with C₇₀.Dedicated to Academician of the RAS N. S. Zefirov (on his 60th birthday).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1840–1842, September, 1995.This study was performed in the framework of the International Research Program of Russia Fullerenes and Atomic Clusters and was financially supported by the Russian Foundation for Basic Research (Project Nos. 93-03-18725 and 93-03-4101).     

Addition of carbon-centered radicals to C60. Determination of the rate constants by the spin trap method

The rate constants of addition of the^.CMe₃,^.CH₂Me,^.CH₂(CH₂)₃Me,^.CH₂Ph,^.CH₂CH=CH₂, and^.CH(Me)Et radicals to fullerene C₆₀ were determined by the method of competitive addition of free radicals to spin traps. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp 2369–2372, December, 1999.     

ESR study of spin-adducts of phosphoryl radicals with methano[60]fullerenes

The influence of structurally different methanofragments attached to [60]fullerene on the spectral parameters of the spin-adducts of phosphoryl radicals with these compounds was studied by ESR spectroscopy. The main direction of attack of phosphoryl radicals is the same fullerene hemisphere to which the methanofragment is attached. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 5, pp. 845–848, May, 2000.     

Allylic radicals as intermediates of free-radical phosphorylation of fullerene-70

Multiple addition of photochemically generated · P(O)(OMe)₂ radicals to C₇₀ results in the formation of allylic radicals with three and five phosphoryl groups.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 222–223, January, 1993.     

ESR study of formation of allylic radicals in simultaneous photochemical generation of phosphoryl and carbon-centered radicals in the presence of C60 fullerene

Allylic radicals resulting upon simultaneous photochemical generation of phosphoryl [^.P(O)(OPrⁱ)₂] and carbon-centered [^.C(O)OMe,^.CH₃,^.CCl₃] radicals in saturated toluene solutions of C₆₀ have been studied by the ESR method. The donor-acceptor properties of carbon-centered radicals determine the positions of phosphoryl groups in the allylic system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2422–2424, December, 1995.This work was performed under terms of the Russian Interdisciplinary Scientific and Technical Program Fullerenes and Atomic Clusters and was financially supported by the Russian Foundation for Basic Research (Project Nos. 93-03-18725 and 93-03-4101) and the International Scientific and Technical Center (Grant No. 079 (B)).     

Addition of Me2·CCN,Me2·CPh,and CCl3CH2·CHPh radicals to fullerene C60

The rate constants for addition of the Me₂ ^·CCN, Me₂ ^·CPh, and CCl₃CH₂ ^·CHPh radicals to fullerene C₆₀ at 22 °C were determined by ESR spectroscopy using spin trapping technique.     

The ESR study of the influence of fluorinated alcohols on spin-adducts of phosphoryl radicals with C60 and C70: a change of magnetic resonance parameters and exclusive formation of monoadducts

Complex formation of^.C₆₀P(O)(OPrⁱ)₂ or three isomers of^.C₇₀P(O)(OPrⁱ)₂ with fluorinated alcohols CF₃CH₂OH (1), (CF₃)₃COH (2), and (CF₃)₂CHOH (3) results in an increase in the hyperfine splitting constants with the³¹P nucleus by approximately 3–4 G. Only monoadducts are formed when alcohols1–3 are added to toluene saturated solutions of Hg[P(O)(OPrⁱ)₂]₂ and C₆₀ under photochemical conditions of multi-addition of phosphoryl radicals to C₆₀. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1869–1871, September, 1998.     

An ESR study of radical reactions of C60 and C70

The results of ESR spectroscopic studies of radical reactions of fullerenes are presented. Reactivities of radicals of various chemical natures with respect to C₆₀ and C₇₀, delocalization of the unpaired electron in monofullerenyl radicals, and their reactivity are considered. The examples of dynamic effects in the ESR spectra of fullerenyl radicals, associated with the hindered rotation of the attached radicals, are presented. Characteristic features of the structures of the spin adducts resulting from polyaddition of free radicals to fullerenes and of fullerenyl radicals containing ²-bonded metaIloco mplexes are discussed.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2396–2406, October, 1996.     

ESR study of spin-adducts of trimethylaminoboryl radicals with fullerene C60

It was established by ESR that trimethylaminoboryl radicals formed by UV irradiation of BH₃NMe_6w in the presence of di-tert-butyl peroxide in saturated benzene solutions of fullerene C₆₀, add to fullerenes to give C₆₀-BH₂NMe₃ spin-adducts. The latter undergo dimerization with a rate constant ofca. 2.5 · 10⁶ L mol^–1 s^–1. A more prolonged photolysis of excess BH₃NMe₃ in a benzene solution of C₆₀ results in multiple addition of the trimethylaminoboryl radicals to the fullerene to give stable radicals C₆₀[BH₂NMe₃]_n.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 673–675, April, 1994.     

Interaction of Phosphoric Anhydride with CH-, NH-, PH-, SH-Acids

Abstract

Phosphoric anhydride interacts with different CH-, NH-, PH-, SH-acids with the formation of corresponding amidophosphates and esters.     

Study of ESR spectra of fullerene C60 doped with magnesium and mercury

An increase in the intensity of the ESR signal and of its g value was observed in the course of annealing of the diamagnetic product of the reaction between magnesium amalgam and a toluene solution of C₆₀. The formation of a crystalline substance Mg_rC₆₀ with semiconductor properties was assumed. The ESR spectra of the products of vapor-phase synthesis of MgC₆₀ and Hg_rC₆₀ were recorded.Translated fromlzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2256–2258, September, 1996.     

ESR study of radical adducts of dialkoxyphosphoryl radicals with (η2-C60)lrH(CO)(PPh3)2 and (η2-C60IrH(8H12)(PPh3)

The reaction of phosphoryl radicals with (η²-C₆₀)lrH(CO)(PPh₃)₂ and (η²-C₆₀IrH(₈H₁₂)(PPh₃) was shown (ESR) to result in the formation of isomers differing in the constants of hyperfine interaction (HFI) with³¹P nuclei,g-factors, and linewidths. It is likely that the addition of phosphoryl radicals at a distance of two-three bond lengths from the metallofragment is predominant. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 870–872, April, 1997.     

Kinetics of the decay of nitroxyl radicals during polymerization of a complex of acrylamide with bismuth nitrate

Kinetics of the decay of nitroxyl radicals during spontaneous polymerization of complexes of acrylamide (AAm) with Bi^III nitrate has been studied by ESR. From a comparison of the experimental and calculated kinetic curves, the initiation rate constant of polymerization has been determined. The approach proposed is suitable for determining the main kinetic characteristics of other polymerizable nonparamagnetic AAm complexes with metal nitrates.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1572–1575, September, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No93-03-4162).     

An ESR study of the products of multiple addition of diisopropoxyphosphoryl radicals to C60

The ESR spectra of the radicals resulting from the multiple addition of diisopropoxyphosphoryl radicals to C₆₀ have been studied. The formation of six different types of radical adducts was detected. A structure for the stable product, characterized by hyperfine coupling of the unpaired electron with two phosphorus nuclei, was proposed. The unpaired electron in C₆₀P(O)(OPrⁱ)₂ is delocalized in the same way as in alkylfullerenyl radicals,i.e., mainly over the two six-membered rings adjacent to the C-CP(O)(OPrⁱ)₂ bond.Translated fromIzvestiya Akademii Nauk. Seriva Khimicheskaya, No. 11, pp. 2679–2682, November, 1996.     

Stable fluoroaliphatic radicals containing functional groups: Synthesis and reactivity

β-Fluorosulphatoperfluoroalkyl radicals (3, 7 and 8) are obtained by the reaction of fluoroolefins (HFP trimer and dimer, and perfluoro4 4-dimethylpent-2-ene, respectively) with (FSO₃)₂. The pure β-fluorosulphatotetrafluoroethylperfluorodiisopropylmethyl radical (3) has been isolated and converted to the perfluoroacetyldiisopropylmethyl radical (4) under the action of CsF. The reaction of radicals 3,7 and 8 with SbF₅ leads to the replacement of the FSO₃ group by a fluorine atom. The ability of the FSO₃ group in β-fluorosulphatoperfluoroalkyl radicals to play the role of a leaving group is explained by the stabilizing effect of the unshared electron on the adjacent carbocation centre.     

Quantum chemical modeling of the addition reactions of 1‐n‐phenylpropyl radicals to C60 fullerene

Modeling of the addition of various radicals to C₆₀ fullerene is currently an active research area. However, the radicals considered are not able to adequately model polymeric radicals. In this work, we have performed a theoretical study of the possible reactions of C₆₀ fullerene with 1‐n‐phenylpropyl radicals, which are used to model polystyrene radicals. Several possible ways of subsequent addition of up to four 1‐phenylpropyl radicals to C₆₀ have been analyzed, the structures of the intermediates have been defined and thermal properties, such as the activation enthalpies of the corresponding reactions, have been calculated using density functional theory with the approximation of PBE/3z. It is shown that the topology of the spin density distribution on the fullerenyl radical causes regioselectivity for further radical addition. According to the energetic characteristics of the reactions, we assume the possibility of formation of products of one‐, two‐, three‐, and four‐ addition of the growth radical to the fullerene core in radical polymerization of styrene in the presence of C₆₀ fullerene. © 2016 Wiley Periodicals, Inc.