Synthesis of Linear Cucurbit[7]uril Pendent Copolymers Through
Radical Polymerization: Polymers with Ultra-High Binding Affinity
Hao Chen,1,2 Haili Ma,1,2 Yebang Tan1,2
of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People’s
Republic of China
2The Key Laboratory of Special Functional Aggregated Materials, Ministry of Education,
Shandong University, Jinan 250100, People’s Republic of China
1School
Supporting Information
Experimental
Materials
CB[7] and 3,3’-(Octane-1,8-diyl)-bis-(1-ethyl-imidazolium) dibromide (C8bim) were synthesized
following
literature
procedures.1,2
1,8-dibromooctane,
4,4’-dipyridyl,
L-phenylalanine,
hydroxymethylferrocene, (ferrocenylmethyl)trimethyl ammonium iodide and 1-adamantanamine
hydrochloride were purchased from J&K Scientific. 4-vinylbenzyl chloride was received from
Acros Organics. 1-Ethylimidazole was received from Strem Chemical Inc.. Spermine
tetrahydrochloride and 1,6-diaminohexane dihydrochloride were received from TCI. All of the
chemicals were used without further purification.
Instruments
NMR tests were conducted by using a Bruker Avance 400 NMR spectrometer at 298 K. Mass
spectrometry (MS) was tested on Agilent 6520 accurate mass Q-TOF. GPC experiments were
performed on Agilent 1260 – Varian 390-LC equipped with PL aquagel-OH MIXED-H 8 µm
column.
Turbidity
measurements
were
employed
with
Persee
TU1901
spectrophotometer. ITC experiments were carried on MicroCal iTC200 at 298 K.
Synthesis of monohydroxy CB[7] (HOCB[7])
ultraviolet
A mixture of C8bim (0.399 g, 0.86 mmol) and CB[7] (1.0 g, 0.86 mmol) was dissolved in 100 mL
deionized water. The solution was heated to 70 ˚C under nitrogen atmosphere and (NH4)2S2O8
(0.228 g, 1.0 mmol) was following added. The solution was heated at 85 ˚C for 5 h and
concentrated to 30 mL after the reaction. The concentrated solution was left to stand overnight and
the precipitate was removed through filtration. The supernatant was concentrated to 10 mL
through rotate evaporation for column separation. HOCB[7] was obtained as a host-guest complex
with C8bim through column separation with CHP-20P macroporous resin (0.184 g, 12.9 %).
Detailed characterization of HOCB[7] including 1H NMR,
13
C NMR, 1H-1H COSY, HQBC and
MS spectrum were listed below.
Figure S-1 1H NMR spectrum of HOCB[7] in D2O.
Figure S-2 1H-1H COSY NMR spectrum of HOCB[7] in D2O.
Figure S-3 13C NMR spectrum of HOCB[7] in D2O (supported with excess 1,6-aminohexane
dihydrochloride)
Figure S-4 HMQC spectrum of HOCB[7] in D2O
Figure S-5 Q-TOF mass spectrum of C8bim·HOCB[7]
Synthesis of 4-vinylbenzyloxy CB[7] (4VBOCB[7])
C8bim·HOCB[7] (96 mg, 0.058 mmol) was dispersed in 1 mL anhydrous DMF, then 5 mL
anhydrous DMSO was slowly added and the suspension could be dissolved under stirring. NaH
(34 mg, 1.42 mmol) was added after the solution cooled down to 0 ˚C under nitrogen atmosphere
and the mixture was stirred for 2 h. After that 4-vinylbenzyl chloride (211 μL, 1.49 mmol) was
added, the solution was slowly recovered to room temperature and reacted for 8 h. 4VBOCB[7]
can be obtained with firstly precipitated with 50 mL ether and then washed with 3 × 20 mL
methanol (70 mg, 93%). Detailed characterization of 4VBOCB[7] including 1H NMR, 13C NMR,
1
H-1H COSY, HQBC and MS spectrum were listed below.
Figure S-6 1H NMR spectrum of 4-VBOCB[7] in D2O. (Due to the recognition of CB[7] cavity to
the 4-vinylbenzyl group, this compound was supposed to self-assemble which is indicated by
high-field shift of its aromatic hydrogen).
Figure S-7 1H NMR spectrum of 4-VBOCB[7] in D2O (supported with excess 1,6-aminohexane
dihydrochloride to disrupt the self-assembly)
Figure S-8 1H-1H COSY NMR spectrum of 4-VBOCB[7] in D2O (supported with excess
1,6-aminohexane dihydrochloride)
Figure S-9 13C NMR spectrum of 4-VBOCB[7] in D2O (supported with excess C8bim, red squares
represent the signal of C8bim)
Figure S-10 HMQC spectrum of 4-VBOCB[7] in D2O (supported with excess C8bim, red squares
represent the signal of C8bim)
Figure S-11 Q-TOF mass spectrum of C8bim·4-VBOCB[7]
Typical synthesis procedure of the CB[7] pendent copolymers [the synthesis procedure of
poly(4VBOCB[7]-co-NIPAA) was used as the example]
The synthesis procedure of 4VBOCB[7] copolymerized with N-isopropyl acrylamide (NIPAA)
was used as a typical example. 4VBOCB[7] (65 mg, 0.050 mmol) and C8bim (80 mg) were
dissolved in 25 mL pure water in a 50 mL flask and NIPAA (0.3 g, 2.65 mmol) was following
added. The flask was firstly vacuumized and then filled with nitrogen for 3 times. After 30 min, a
solution contains 1.2 mg (NH4)2S2O8 was firstly injected into the solution and a solution contains
0.44 mg NaHSO3 was then added. The solution was heated at 25 ˚C for 5 h and then 30 ˚C for
another 5 h. Unreacted monomer, C8bim and other soluble impurities can be removed through
dialysis with a MWCO 3500 semi-permeable membrane in 0.2 % CB[7] solution for 2 days and in
pure water for another 5 days. At last, trace insoluble impurities were removed by filtration. The
CB[7] pendent copolymer, poly(4VBOCB[7]-co-NIPAA), was obtained as colorless solid through
desiccate the solution (0.212 g).
For acrylamide and N,N’-dimethylacrylamide based CB[7] pendent copolymers, due to the limited
4VBOCB[7], they were synthesized with same method except the amount of all materials and
solvents decreased in proportion. Their 1H NMR spectra and molecular weight were listed below.
Figure S-12 1H NMR spectrum of poly(acrylamide-co-4VBOCB[7])
Figure S-13 1H NMR spectrum of poly(N,N’-dimethylacrylamide-co-4VBOCB[7])
Table S-1 Basic characterization of CB[7] pendent copolymers
Mn (g mol-1)
Mw/Mn
CB[7] moiety content (mol%)
Poly(4VBOCB[7]-co-NIPAA)
2.10 × 105
1.69
0.86
Poly(4VBOCB[7]-co-AM)
4.52 × 105
8.79
0.72
Poly(4VBOCB[7]-co-DMA)
2.02 × 105
1.67
0.75
Isothermal titration calariemetry (ITC) experiments
In ITC experiments, solution of guest molecules were used as titrant with the concentration of 0.5
– 5 mM to titrate poly(4VBOCB[7]-co-NIPAA) (concentration of CB[7] moiety is 0.05 – 0.5 mM).
The spinning speed of the needle is set as 600 rpm and all the experiments were conducted at 298
K in pure water. All the data were fitted with 1:1 binding model.
Figure S-14 ITC plots of poly(4VBOCB[7]-co-NIPAA) titrated with L-phenylalanine
Figure S-15 ITC plots of CB[7] titrated with dimethyl viologen dichloride (compete with 10 mM
L-phenylalanine)
Figure S-16 ITC plots of poly(4VBOCB[7]-co-NIPAA) titrated with spermine tetrahydrochloride
(compete with 10 mM L-phenylalanine)
Figure S-17 ITC plots of poly(4VBOCB[7]-co-NIPAA) titrated with 1,6-diaminohexane
dihydrochloride (compete with 10 mM L-phenylalanine)
Figure S-18 ITC plots of poly(4VBOCB[7]-co-NIPAA) titrated with hydroxymethylferrocene
(compete with 10 mM L-phenylalanine)
Figure
S-19
ITC
plots
of
poly(4VBOCB[7]-co-NIPAA)
titrated
with
(ferrocenylmethyl)trimethylammonium iodide (compete with 10 mM 1,6-diaminohexane
dihydrochloride)
Figure S-20 ITC plots of poly(4VBOCB[7]-co-NIPAA) titrated with 1-adamantanamine
hydrochloride (compete with 10 mM dimethyl viologen dichloride).
References
[1] A. Day, A. P. Arnold, R. J. Blanch, B. Snushall, J. Org. Chem. 2001, 66, 8094-8100.
[2] N. Zhao, G. O. Lloyd, O, A. Scherman, Chem. Commun. 2012, 48, 3070-3072.