Esters are formed from carboxylic acids and alkyl iodides upon treatment with t-butyl hypochlorite and iodine in carbon tetrachloride. Evidence is presented for a heterolytic mechanism whereby the iodine in the alkyl halide is replaced by the acyloxy-group of the acyl hypoiodite in the presence of iodine monochloride.

Key indicators: single-crystal X-ray study; T = 200 K; mean (C-C) = 0.003 Å; R factor = 0.021; wR factor = 0.059; data-to-parameter ratio = 18.5.The title compound, C 20 H 13 I, is a halogenated derivative of triptycene. The molecule shows crystallographic as well as non-crystallographic C 3 symmetry. The asymmetric unit comprises one third of the molecule. Dispersive IÁ Á ÁI contacts [IÁ Á ÁI = 3.6389 (3) Å ] connect the molecules into dimers. The shortest centroid-centroid distance between two -systems is 3.8403 (12) Å . Related literatureFor the crystal structures of 1-bromotriptycene, 9,10-dibromotriptycene and 10-bromo-9-triptycyl iodoformate, see

Nitrosotriptycene is found to be a potentially useful spin trap when used in organic solvents; the esr spectra of its spin adducts are simple, but they may show marked temperature dependence due to restricted rotation. Nitrosotriptycene traps primary alkyl radicals with a rate constant of ca. 2 × 107 L mol−1 s−1 at 40°C in benzene.

Für die Bildung der Ester (IV) aus den Säuren (I) und den Jodiden (II) in Tetrachlormethan oder Nitrobenzol in Gegenwart von tBu‐OCl/Jod wird ein heterolytischer Mechanismus vorgeschlagen.