Chemistry Reference
In-Depth Information
with zwitterionic [3,3
0
-Co(8-C
4
H
8
O
2
-1,2-C
2
B
9
H
10
)(1
0
,2
0
-C
2
B
9
H
11
)] [
57
,
58
]. Nucleo-
philic groups on the porphyrin macrocycle, such as hydroxy and pyridyl, efficiently
open the dioxane ring of [3,3
0
-Co(8-C
4
H
8
O
2
-1,2-C
2
B
9
H
10
)(1
0
,2
0
-C
2
B
9
H
11
)], pro-
ducing porphyrins bearing Co(III) bis(dicarbollide) linked via a short PEG linkage
[
57
-
62
]. In the absence of these groups, metal-free porphyrins produce the
corresponding mono- and di-alkylated derivatives [
61
]. Since the Co(III) bis
(dicarbolide) is negatively charged, porphyrins
23
and
24
are octa- and tetra-
anionic, respectively. On the other hand, when pyridylporphyrins are used as the
starting materials for the ring opening reaction of [3,3
0
-Co(8-C
4
H
8
O
2
-1,2-C
2
B
9
H
10
)
(1
0
,2
0
-C
2
B
9
H
11
)], zwitterionic carboranylporphyrins are formed [
57
,
61
,
62
].
