Gebändigt: das hoch reaktive Oxoniumion

Abstract

Das dreiwertige Sauerstoffatom als Strukturelement im tricyclischen Gerüst von 1–3 verleiht dieser „ungewöhnlichen“ Klasse von tertiären Oxoniumionen beispiellose Stabilität. Das Kation 1 ist am wenigsten reaktiv, es kann ohne erkennbare Zersetzung 72 h in siedendem Wasser erhitzt werden.

The Quest for Tetracoordinated Halonium Ions: A Theoretical Investigation

“…Another unusual type of bond formation, this time not in contrast to the octet rule, is further binding of remaining lone pairs of the main group VI and VII elements to carbocations. Oxonium ions 2 (R 3 O + ) are widely known as intermediates of various transformations in organic chemistry; that have also been isolated and have been used as Meerwein’s salt in synthesis . However, their halogen counterparts, the halonium ions 5 (R 2 Hal + ), are less famous.…”

Caged Chalcogens: Theoretical Studies on a Tetracoordinated Oxonium Dication and Its Higher Homologues

“…Recently, Olah reported the synthesis of an analogous oxaadamantane 3 . Whereas the two latter examples are also highly reactive compounds that immediately undergo ring-opening reactions in the presence of water or other nucleophiles, Mascal presented a series of tamed oxonium ions 4 − 6 that lost their typical reactivity toward nucleophiles . Most surprisingly, NMR spectra of cation 4 could even be recorded in water.…”