Chemistry Reference
In-Depth Information
i
Pr
i
Pr
i
Pr
i
Pr
9
10
11
R
R
R
R
R
R
R
R = NBu
2
R
12
13
14
Scheme 5 Macrocycles with benzene units and linear acetylene linkers
R
R
R
X
R
R
X
X
R
R
X
X
R
R
X
R
R
R
R
R
R
X
R
R
X
X
R
X
R
X
R
X
R
R
16a
X = H
16b
X = Cl
R
17a
X = H
17b
X = Cl
15
R
R
=
R
Scheme 6 Macrocycles with two benzene units and three long linkers as fullerene precursors
Compounds 15 and 16, in which two benzene units are connected by three
carbon 16-atom linkers, were designed for precursors of fullerene C
60
(Scheme
6
).
These compounds were synthesized by dimerization of terminal alkynes by oxida-
tive coupling. Macrocycle 15 has a twisted
D
3
symmetric structure with the two
benzene rings separated by 3.3
˚
as revealed by X-ray analysis [
46
,
47
]. The
calculation suggested that racemization of 15 proceeded rapidly even at low
temperature. Compounds 16 gave an ion peak of C
60
+
formed via extrusion of
indane followed by polyyne cyclization and extrusion of hydrogen or chlorine
atoms in their MALDI-TOF mass spectra [
48
-
50
]. Compounds 17 have an extra
three
p
-phenylene units in the 3D framework [
51
]. The mass spectrum of chloro
derivative 17b gave an ion peak assignable to C
78
-
.
