No abstract

Cycloaddition of nitrile oxides to [60]fullerene led to [60]fullereno[1,2‐d]isoxazole derivatives 1b–d. [60]Fullereno[1,2‐d]isoxazole (1a) is the corresponding cycloadduct with fulminic acid. X‐ray structure analyses of compound 1b and 1e were determined.

The photodecomposition of a-methoxydeoxybenzoin (1) and a,a-dimethoxydeoxybenzoin (2) was investigated both in the absence and in the presence of 1,l-diphenylethylene. The resulting products indicate that benzoyl radicals add to the olefinic double bond (initiation of polymerization), whereas the a-methoxybenzyl radicals generated from 1 do not add to the olefinic double bond (no initiation), but preferentially combine with other radicals (termination of polymerization). This reaction is largely suppressed in the case of a,adimethoxybenzyl radicals generated from 2 owing to sequential fragmentation into inactive methylbenzoate and highly reactive methyl radicals which add to the olefinic double bond and thus contribute to the initiation. *) Part 2: H.

The mechanism of biscitraconimides (BCI) as antireversion agents for sulfur vulcanized diene rubber was investigated choosing squalene as a model substrate. Curing of squalene with sulfur in the presence of accelerator, activator and BCI at 170°C gave BCI bridged adducts. The products were identified by spectroscopic methods as being results of a Diels-Alder reaction of BCI (dienophile) with conjugated polyenes that are formed as a result of reversion. The rate at which the sulfur network degrades is comparable to the rate in which BCI adduct is formed. As a result of this, a nearly constant crosslink density is obtained after optimum cure time (t90). Based on this concept, the advantage of using 1,3-bis-(citraconimidomethyl) benzene (BCI-MX), a representative of the BCI-class, in NR based compounds is examined.

Anthracene groups have been linked to [60]fullerene by the [3+2] cycloaddition of the corresponding nitrile oxides or by esterification with a [60]fullerenol. The anthryl groups of the fullerene derivatives 3, 7, and 10 react readily with singlet oxygen to form the 9,10‐epidioxides 4, 8, and 12 under photooxidation. The anthryl moiety of the fullerenol ester 10 also reacts with the fullerene skeleton to form the stable intramolecular Diels‐Alder adduct 11.