Cobalt-mediated synthesis of angular [4]phenylene: structural characterization of a metallacyclopentadiene(alkyne) intermediate and its thermal and photochemical conversion.
[reaction: see text] The first X-ray crystal structure of a mononuclear metallacyclopentadiene(alkyne) complex has been obtained. This type of metallacycle is believed to be the key intermediate in the cobalt-mediated [2 + 2 + 2]cycloaddition of alkynes. Thermal treatment leads to the generation of angular [4]phenylene, the X-ray structural details of which are described. Under photochemical conditions, the cobaltacycle isomerizes to a highly strained (cyclobutadieno)dibenzocyclooctatrienyne complex.
Dosa
Peter I
PI
CLRC Daresbury Laboratory, Warrington, Cheshire, WA4 4AD, UK.
Whitener
Glenn D
GD
Vollhardt
K Peter C
KP
Bond
Andrew D
AD
Teat
Simon J
SJ