Cyclic Polyynes: Generation, Characterization, and Reactions - Polyynes: Synthesis, Properties, and Applications - page 101

FIGURE 6.2 [2 þ 1] type organic precursors of monocyclic carbon clusters.
observation of cyclocarbon was not achieved owing to the extensive frag-
mentation under strong laser power. Dehydro oligomers of 1,1-diethynyl-
cyclopropane such as 7a,b were also prepared by de Meijere et al., from
which extrusion of tetramethylethylene or ethylene would form cyclo[5m]-
carbons [8]. However, it remains to be seen whether these form C 30 and C 60 ,
respectively, by fragmentation in the gas phase. Moreover, radialenes 8a-d
having bicyclo[4.3.1]deca-1,3,5-triene units were prepared which would
produce cyclo[6m]carbons through the isomerization of the corresponding
vinylidene intermediates generated by the loss of the indane fragments [9].
Indeed, the negative mode LD TOF mass spectra of 8a-d exhibited the
peaks due to the corresponding carbon anions (C 18 ,C 24 ,C 30 , and C 36 )