A calixarene-decorated phosphole oxide.
Résumé
A conical calix[4]arene receptor I (9, R = n-Pr) equipped with a benzo[b]phosphole oxide grafted to its upper rim was obtained in six steps by starting from 5-bromo-25,26,27,28-tetrapropyloxycalix[4]arene. The route involved the synthesis of the calixarene intermediate II (5, R = n-Pr, M = electron pair) that bears a 2-(diphenylphosphinyl)phenylethynyl substituent connected to the calixarene wider rim. Under PdII/CuI co-catalysis, mixed phosphane-alkyne 5, when heated at 120°, underwent P-Ph bond cleavage followed by attack of the phosphorus atom onto the carbon-carbon triple bond. The resulting calixarene-phosphole was then oxidized to form the corresponding phosphole oxide 9. Compd. 9 luminesced strongly under UV irradn. The solid-state structure of a deriv. of phosphane-alkyne 5, AuCl complex (8, shown as II, M = AuCl), was established by a single-crystal x-ray diffraction study. Borane complex (6, shown as II, R = n-Pr, M = BH3) and oxide of 5 (7) were also prepd. [on SciFinder(R)]