Publisher Summary The dimerization of cation radicals of simple benzene derivatives is usually accompanied by the formation of the corresponding biphenyl derivative. This, by virtue of the extended conjugation is more easily oxidized, and frequently only intractable tars are found as final products. If the reaction medium is carefully selected, so that the biphenyl cation radicals are stable, useful synthetic procedures can be developed. Two mechanisms are probable for the dimerization of cation radicals of anisoles and related compounds. They are termed “radical–radical dimerization” (RRD) and “radical–substrate coupling” (RSC). The oxidation of aromatic hydrocarbons and alkylaromatic compounds in media of low nucleophilicity results in the formation of dimers. The cation radicals of triphenylamines form dimers in high yield when generated in acetonitrile. The products are tetraphenylbenzidines.

Kinetics and mechanisms of reactions of organic cation radicals in solution

Novel intrinsically microporous homopolymers and copolymers derived from PIM-1 monomers (5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethylspirobisindane and 2,3,5,6-tetrafluoroterephthalonitrile) with two additional monomers—tetrahydroxydinaphthyl and tetrafluorotetraoxide thianthrene—are reported as potential materials for membrane-based gas separations. The resulting copolymers prevent efficient space packing of the stiff polymer chains and consequently exhibit analogous behavior to that of PIM-1, the most widely reported polymer in this class of materials. In addition, the copolymerization provides high molecular weight copolymers and low polydispersity if the polymerization reactions were conducted at elevated temperature for an extended period of time. Detailed structural characterization of the new monomers and polymers was determined by 1H and 19F nuclear magnetic resonance spectroscopy (NMR). The thermal properties were detected by differential scanning calorimetry (DSC) and thermogravimetric analysis ...

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Polymers of Intrinsic Microporosity with Dinaphthyl and Thianthrene Segments

2-mm Waveband electron paramagnetic resonance spectroscopy of conducting polymers

The results of studies in the chemistry of disulfides during recent years are surveyed and treated systematically. The structures, methods of synthesis, and the physicochemical and chemical properties of disulfides are examined. The bibliography includes 151 references.

https://iopscience.iop.org/article/10.1070/RC1994v063n09ABEH000115/pdf

The chemistry of disulfides

A practical preparation of terminal alkynes from aldehydes.

In Reaktionsgemischen von Acetylenen RC CR (1) mit R H, CH3, C2H5, C3H7, C4H9, C(CH3)3, C6H5 mit ClSSCl/AlCl3/H2CCl2 oder mit S8/SbCl5/H2CCl2 lassen sich bei 250 K zunachst 1,2-Dithiet-Radikalkationen R2C2S2⊕ (2a – g) und nach Erwarmen auf 300 K zusatzlich 1,4-Dithiin-Radikalkationen R4C4S2⊕ (3) ESR-spektroskopisch nachweisen. Ihre Erzeugung gelingt auch durch Umsetzung von 1,2-Dichlorethen- oder 1,1,2,2-Tetrabrom-ethan-Derivaten mit Na2S2/AlCl3/H2CCl2, die sich zur 33S-Isotopenmarkierung eignet. Nach geometrie-optimierten closed und open shell MNDO-Berechnungen ist sowohl fur H2C2S2 wie fur H2C2S⊕ die Vierring-Struktur bevorzugt; hohe Spindichte in der Disulfid-Gruppierung erklart die beobachteten grosen g-Faktoren und 33S-Koppungskonstanten.



Radical Ions, 71. Oxidative Sulfurization of Acetylenes to 1,2-Dithiete and 1,4-Dithiine Radical Cations



In reaction mixtures of acetylenes RC CR (1) with R H, CH3, C2H5, C3H7, C4H9, C(CH3)3, C6H5 and ClSSCl/AlCl3/H2CCl2 or S8/SbCl5/H2CCl2 at 250 K first 1,2-dithiete radical cations R2C2S2⊕ (2a – g) and after warming to 300 K in addition 1,4-dithiine radical cations R4C4S2⊕ (3) are characterized ESR spectroscopically. Their generation can also be accomplished by the reaction of 1,2-dichloroethene or 1,1,2,2-tetrabromoethane derivatives with Na2S2/AlCl3/H2CCl2, a method well suited for 33S isotope marking. According to geometry-optimized closed and open shell MNDO calculations, the preferred structures both for H2C2S2 and for H2C2S⊕ are four-membered rings; high spin density in the disulfide moiety allows to rationalize the observed large g values and 33S coupling constants.

Radikalionen, 71. Oxidative Schwefelung von Acetylenen zu 1,2-Dithiet- und 1,4-Dithiin-Radikalkationen

Novel 1,2-dithiete derivatives R2C2S2 with R = [sbnd]C(CH3)3 and [sbnd]C(CH3)2[sbnd]CH2[sbnd]CH2[sbnd]CH2[sbnd]C(CH3)2[sbnd] are readily oxidized by the one-electron transfer system AlCl3/H2CCl2 to their radical cations. The single line ESR spectra, on high amplification, exhibit 33S satellites in natural abundance. Both the ESR data, i.e. rather large g values and 33S hyperfine coupling constants as well as MNDO closed and open shell calculations for the parent molecule H2C2S2 illustrate that spin and positive charge are predominantly located in the SS bridge of the four-membered ring.

Radical ions 561,2 one-electron oxidation of 1,2-dithiete derivatives

Elektronenspinresonanz‐Untersuchungen zur Schwefel‐Katalyse der technischen Benzol‐Dichlorierung

The single electron oxidation of 14 alkyl and alkoxy substituted diaryldisulfides by AlCl3H2CCl2 has been investigated by ESR/ENDOR spectroscopy. The radical cations observed prove the following skeletal rearrangements: Those with ring hydrogens in ortho positions to the disulfide bridge preferentially form thianthrene derivatives. The isomeric dinaphthyl disulfides react differently, the 2,2′-isomer yielding the dibenzothianthrene radical cation and the 1,1′-isomer the well-known naphthalene-1,8-disulfide radical cation. For all diaryl disulfides with completely alkyl- or methoxy-blocked ortho positions, oxidative desulfuration is observed. As substantiated by additional 2D and 33S isotope marking, the bis(2,5-dimethoxyphenyl)disulfide reacts both to the corresponding thianthrene derivative as well as via desulfuration to the radical cation of the monosulfide. Accompanying cyclovoltammetric and photoelectron spectroscopic measurements prove that all ESR spectroscopically detected radical cations...

RADIKALIONEN 891,2 EINELEKTRONEN-OXIDATIONEN VON DIARYLDISULFIDEN MIT AlCl3/H2CCl2

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1145. DOI:10.1002/anie.198211450

Peter Rittmeyer

Papers

Radikalionen, 71. Oxidative Schwefelung von Acetylenen zu 1,2-Dithiet- und 1,4-Dithiin-Radikalkationen

Radical ions 561,2 one-electron oxidation of 1,2-dithiete derivatives

Elektronenspinresonanz‐Untersuchungen zur Schwefel‐Katalyse der technischen Benzol‐Dichlorierung

RADIKALIONEN 891,2 EINELEKTRONEN-OXIDATIONEN VON DIARYLDISULFIDEN MIT AlCl3/H2CCl2

Electron Spin Resonance Studies of the Sulfur Catalysis of the Industrial Dichlorination of Benzene