SUPRAMOLECULAR CHEMISTRY
9
intermolecular aggregation properties were investigated.
The identity of the synthesised compounds was confirmed
by NMR spectroscopy and mass spectral analysis. The
supramolecular assembly processes were monitored and
illustrated by concentration-dependent 1H NMR, 2D NMR,
SEM, DSC and viscosity measurements. The fluorescent
results show that the assemblies display fluorescence
weakening with the increase of concentration at high con-
centrations, and the formation of the excimers is found in
the guests with protonated amine groups. The results
suggest that the spiro structure building blocks probably
favour the formation of linear supramolecular polymers,
not cyclic species, which is most likely due to the substitu-
ent effects, and further study needs to be done to find the
precise reasons leading to such different supramolecular
polymerisation behaviour.
and tetrakis(triphenylphosphine)palladium [Pd(PPh3)4]
(110 mg) were added to a 100 mL two-necked round-
bottomed flask. Toluene (10 mL), THF (10 mL), KF and
K2CO3 each 1mol/L hydroxide (3 mL) were added to
the flask under nitrogen. The mixture was refluxed for
24 h under a nitrogen atmosphere. After the mixture
had been cooled to room temperature, the mixture
was poured into brine. Then, the mixture was
extracted with dichloromethane, the two phases
were separated, and the aqueous phase was extracted
twice with dichloromethane. The combined organic
extracts were washed three times with water, dried
over MgSO4, evaporated, and purified with column
chromatography (silica gel, ethyl acetate–dichloro-
methane (4/1) as eluent) to yield 670 mg (Yield:
37.0%) of 1a as a light yellow semi-solid. 1H NMR
(400 MHz, Chloroform-d) δ 7.79–7.75 (d, J = 8.1 Hz,
2H), 7.57–7.53 (d, J = 7.5 Hz, 2H), 7.51 (s, 2H), 7.39–7.33
(d, J = 10.3 Hz, 4H), 7.20–7.16 (d, J = 8.2 Hz, 2H),
7.11–7.04 (m, 8H), 4.45–4.26 (m, 16H), 3.88–3.75 (m,
16H), 3.69–3.60 (m, 16H). 13C NMR (400 MHz,
Experimental
Materials and methods
Chloroform-d)
δ 148.23, 137.16, 125.90, 123.63,
All reagents were obtained from commercial sources with-
out further purification unless otherwise mentioned. The
compounds of 4a, 4b were prepared according to the
literature procedures (51, 52). NMR was recorded on
a Bruker 400 MHz spectrometer using CDCl3, MeOD-d4,
DMSO-d6 and CDCl3–CF3COOD (3:1, v/v) as solvents.
MALDI-TOF mass spectra were taken on a Bruker BIFLEX III
ultra-high resolution Fourier transform ion cyclotron reso-
nance (FT-ICR) mass spectrometer with α-cyano-4-hydroxy-
cinnamic acid as matrix. DSC measurements were acquired
using a Shimadzu Instruments DSC-60A. DSC data were
collected from 30°C to 210°C at a rate of 5°C/min for both
of the baseline and sample. SEM images were obtained
using a Hitachi S-4800 field-emission scanning electron
microscopy. Specific viscosity was obtained using
a Viscosimeter (0.5–0.6 mm). Absorption spectra (1 μM
increase to 50 mM in CHCl3–CF3COOH, 3:1, v/v) were mea-
sured with a Shimadzu UV-3600 spectrometer at 25°C, and
emission spectra (1 μM increase to 50 mM in CHCl3–CF3
COOH, 3:1, v/v) were recorded on a Shimadzu RF-5301(PC)
luminescence spectrometer. The fluorescence decay was
measured using an Edinburgh FLSP920 fluorescence spec-
trophotometer equipped with a xenon arc lamp (Xe900).
123.40, 122.27, 121.10, 120.20, 116.92, 116.54, 116.25,
115.75, 69.29, 69.04, 68.48, 68.25, 67.76, 67.62, 67.51,
67.31, 67.21, 55.41, 40.38, 31.77, 29.99, 29.71, 29.21,
23.87, 22.59, 14.09 . MS (Madi-Tof): calcd [M]+
1282.717, [M+Na]+ 1305.706, Found: [M]+ 1282.672,
[M+Na]+ 1305.672, [M+K]+ 1321.673.
The methods for preparing 1b are the same. Yield:
30.4%. The proton NMR spectrum of 1b is shown in
Figure S6. 1H NMR (400 MHz, Chloroform-d) δ 7.90–7.84
(d, J = 7.9 Hz, 4H), 7.56–7.52 (dd, J = 8.0, 1.6 Hz, 2H),
7.40–7.35 (t, J = 7.5 Hz, 2H), 7.14–7.09 (t, J = 7.5 Hz, 2H),
6.95 (s, 2H), 6.94–6.91 (d, J = 2.1 Hz, 2H), 6.89–6.84 (m,
8H), 6.84 (s, 2H), 6.83–6.77 (t, J = 8.4 Hz, 4H), 4.17–4.08
(m, 16H), 3.93–3.84 (dt, J = 8.5, 5.1 Hz, 16H), 3.83–3.77
(d, J = 3.4 Hz, 16H). 13C NMR (400 MHz, Chloroform-d) δ
149.74, 148.92, 148.91, 148.88, 148.58, 140.46, 134.50,
127.90, 127.75, 126.60, 124.29, 122.26, 121.42, 120.23,
120.18, 120.07, 114.06, 113.98, 113.55, 71.24, 71.19,
69.91, 69.85, 69.76, 69.44, 69.37, 69.34, 29.72 . MS (Madi-
Tof): calcd [M]+ 1208.513, [M+Na]+ 1230.421. Found (%):
[M]+ 1207.411, [M+Na]+ 1230.421, [M+k]+ 1246.416.
Synthesis of compounds 2a and 2b
2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9‘-
spirobi[fluorene] (5) (1.42 g, 2.5 mmol), N-benzyl-1-(4-bro-
mophenyl)methanamine (1.72 g, 6.25 mmol), and tetrakis-
(triphenylphosphine)palladium [Pd(PPh3)4] (180 mg) were
added to a 100 mL two-necked round-bottomed flask.
Toluene (15 mL), THF (15 mL), KF and K2CO3 each 1mol/
Synthetic procedures
Synthesis of compounds 1a and 1b
2,2‘-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(4,4,5,5-tetra-
methyl-1,3,2-dioxaborolane) (4a) (0.85 g, 1.5 mmol),
4-Bromo-dibenzo-24-crown-8 (1.62 g, 3.08 mmol),