Chemistry Reference
In-Depth Information
Fig. 1.3
X-ray crystal structure of Q[10] and twisted tQ[14]
Moreover, a number of substituted cucurbit[
n
]urils (SQ[
n
]s) and their deri-
vates were reported during the last decade. Stoddart and coworkers first reported
an alkyl-substituted cucurbit[5]uril, decamethylcucurbit[5]uril (Me
10
Q[5]) by self-
assembly of dimethylglycouril; unexpectedly, none of its homologs were found in
1992 [
12
]. Following this discovery, a number of fully and partially substituted
Q[
n
] derivatives have been reported since 2001. These include the fully or par-
tially substituted (CyH)
n
Q[
n
]s (cyclohexano
=
CyH;
n
=
5-8) [
13
], Me
12
Q[6]
[
14
,
15
], and (CyP)
n
Q[
n
] [
16
], the partially substituted Ph
2
Q[6] [
17
], HMeQ[6]
[
18
], TMeQ[6] [
19
], (CyH)
2
Q[6] [
20
], and (Me
2
CyP)
n
Q[6] [
14
]. Issacs and
coworkers reported some water soluble, fluorescence-sensitive cucurbit[
n
]uril
analogues, which were obtained starting with S- and C-shaped diastereomeric
methylene-bridged glycoluril dimers [
21
-
23
]. Moreover, they found a series of
glycouril oligomers [
24
] and used these oligomers to synthesize a number of novel
cucurbit[
n
]uril derivates [
24
-
27
]. Kim, Isaacs, and other groups synthesized and
exploited various functionalized Q[
n
]s. For example, in 2003, Kim and cowork-
ers demonstrated the first reactive cucurbit[
n
]urils, perhydroxycucurbit[
n
]urils
[(HO)
2
n
Q[
n
] (
n
=
5-8)], by direct oxidation of Q[
n
]s with K
2
S
2
O
8
in water [
28
].
In particular, Scherman recently reported a monohydroxylated cucurbit[6]uril in
2012 [
29
]. Recently, Isaacs and coworkers also reported a series of functionalized
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