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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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