Supporting Information
for
Advanced Materials, adma.200400661
Wiley-VCH 2005
69451 Weinheim, Germany
Supporting Information
Experimental
Materials
The 1,1,1-tris(p-hydroxyphenyl)ethane (THPE) (Hoechst Celanese) and stannous(II) 2ethylhexanoate Sn(Oct)2 (Sigma), were used as delivered. 4-(Dimethylamino)pyridinium
4-toluenesulfonate (DPTS) was synthesized according to a literature procedure. The εcaprolactone was dried over CaH2 (Mallinckrodt), distilled and stored under N2 prior to
use. Toluene was dried over Na, distilled and stored under N2. The methyl methacrylate
and hydroxyethyl methacrylate (HEMA) were distilled under vacuum and refrigerated
under N2 until used. The dendrimers derived from 2, 2-bis(hydroxymethyl)propionic
acid (Bis-MPA) were prepared according to a literature procedure. The benzyl 2,2’bis(hydroxymethyl) propionate was synthesized according to a literature procedure. All
other compounds were purchased from Aldrich and used as received.
Measurements
Size-exclusion chromatography (SEC) was carried out on a Waters chromatograph
connected to a Waters 410 differential refractometer. Four 5
m Waters columns (300 X
7.7 mm) connected in series in order of increasing pore size (100, 1000, 105, 106 Å) were
used with THF as eluant. The SEC results were calibrated with polystyrene standards.
The thermophysical properties (Tg) were recorded on a Perker-Elmer DSC-7. 1H NMR
spectra were recorded in a solution with a Bruker AM 250 (250 MHz) spectrometer. 13C
NMR spectra were recorded at 62.9 MHz on a Bruker AM 250 spectrometer using the
solvent carbon signal as an internal standard.
NG3 30m SANS beam line at the National Institute of Standards and Technology was
used for SANS experiments. Neutron wavelength and wavelength spread (FWHM) were
8 Å and 0.150, respectively. SAXS experiments were performed at the IMM-CAT at the
Advanced Photon Source at Argonne National Laboratory. The incident X-rays from an
undulator were monochromatized with a Ge (111) crystal to an energy of 7.66 keV. Slits
confined the incidence beam size to either 100 x 100 m (high resolution) or 200 x 200
m (low resolution). An area detector was used with a sample-to-detector distance of
either 2750 mm (high resolution) or 235 mm (low resolution). The high and low
resolution data sets were merged and the background scattering was subtracted carefully
to give the SAXS from the ferrocenyl unit of porogens or pores.
General procedure for the polymerization of
polycaprolactone star-shaped
polymers.
The initator, a second generation dendrimer derived from bis MPA, prepared according to
literature procedures, was distilled and stored in a glove box until used. The initiator and
monomer were charged into a flamed flask and dissolved in 2 mL of toluene. The
temperature was increased to 110 °C and Sn(Oct)2 was added. The polymerization was
continued for 24 hours. The viscous solution was diluted with THF and precipitated in
cold methanol. The bis-MPA units provide exquisite markers for the spectroscopic
analysis of the polymers, as the quartenary carbon is sensitive to the substitution of the
neighboring hydroxyl groups,
and examination of the
13
C NMR spectra demonstrated
that initiation occurred from each of the hydroxyl groups of the dendritic initiator (i.e.,
quantitative initiation giving precise arm number). The polymer was isolated in nearly
quantitative yield:
1
H NMR (CDCl3) δ 7.23–7.31 (m, 5H, –Ph), 4.6 (s, 2H, -OCH2Ph),
4.14 (m, 2H, –CO2CH2–), 3.51–3.55 (m, 1H, CH-O), 2.23–2.27 (m, 2H, –CH2CO2–),
1.78–1.96 (m, 4H, –CH2CHCH2–).
General procedure for the modification of the hydroxy functional end groups of the
poly(ε-caprolactone) initiators for ATRP.
G-1 (6-OH) (8.00 g, 3.20 mmol) was
dissolved in 50 mL of dry THF, and to this solution, triethylamine (1.40 g, 17.75 mmol)
was added. The 2-bromo-2-methylpropionyl bromide (1.58 g, 6.85 mmol) was added
dropwise over a 15 min period and stirring continued at room temperature for 48 hours.
1
H-NMR (CDCl3) δ 1.28–1.40(m, poly, -CH2CH2CH2-), 1.55–1.70 (m, poly, -
CH2CH2CH2-), 1.89(s,6H, CH3), 2.24–2.35 (t, poly, -CH2CO- ), 4.00–4.05 (t, poly, CH2O-), 4.11–4.16 (t, 18H, ,-CH2OH ), 4.31 (2, 12H,-CH3(CH2O)2) ), 6.89–7.07 (dd,
12H, Ph–).
13
C NMR (CDCl3) 17.74, 24.51, 25.47, 28.29, 30.70, 34.05, 46.71, 51.61,
55.88, 64.05, 65.11, 65.70, 120.69, 129.65, 146.23, 148.62, 171.37, 171.57, 172.77,
173.43.
General
procedure
polycaprolactone.
for
G-1
ATRP
(6-Br)
of
methyl
(0.40
g
methacrylate
0.15
mmol)
from
functional
and
dibromo-
bis(triphenylphosphine)nickel(II) (7.00 mg, 0.009 mmol) were charged into a flask,
which was evacuated for 12h and then purged with nitrogen and evacuated . Dry methyl
methacrylate (2.00 g, 20.00
mmol) was added through a rubber septum and allowed to
stir at room temperature until the macroinitiator dissolved. Optionally, toluene or THF
could be added to facilitate the dissolution of the initiator and/or reduce the viscosity of
the polymerization. The reaction flask was placed in a hot oil bath (110°C) and allowed
to react for 5–8 hours. The polymers were isolated in hexane, stirred with methanol and
isolated by filtration.
Monomer Synthesis
δ-(ε-Caprolactone) 2,2-bis(phenyldioxymethyl)propionate
4-Hydroxycyclohexyl 2,2-bis(phenyldioxymethyl)propionate
The 2,2’-bis(phenyldioxymethyl)propionyl chloride (10.0 g, 42.0 mmol) was added to a
THF solution of 1,4-cyclohexanediol (5.70 g, 0.049 mol) and triethylamine (7.42 g, 0.07
mol). After 24 h, CH2Cl2 (1000 mL) was added and the solution was washed with 1M
HCl (3X), water (2X), dried (MgSO4) and concentrated. The product was purified by
column chromatography (silica gel using hexane/ethyl acetate gradient as eluant). Yield
(40%). 1H-NMR (CDCl3) δ 1.01 (s, 3H, –CH3), 1.57–1.61 (m, 4H, CHCH2–), 1.95–2.02
(m, 4H, –CHCH2–), 3.66 (m, 3H, –CCH2OR– and –CHOH), 4.62 (d, ABq, 2H, –
CCH2OR–), 4.99 (m, 1H, –CHPh), 7.22–7.38 (m, 5H, Ar).
4-Ketocyclohexyl 2,2-bis(phenyldioxymethyl)propionate
Pyridinium chlorochromate (PCC) (4.95 g, 0.022 mol) was added to a solution of 5 (5.40
g, 0.019 mol) in CH2Cl2. After 24 h, diethyl ether was added (300 mL) and the mixture
filtered through silica gel. The product was then purified by column chromatography
(silica gel using ethyl acetate/hexane as the eluant): yield 64%. 1H-NMR (CDCl3)
(s, 3H, –CH3), 2.01–2.07 (m, 2H, –COCH2–), 2.12–2.39 (m, 4H, –CHCH2–), 2.50–2.65
(m, 2H, –COCH2–), 3.64 (d, ABq, 2H, –CCH2OR–, J=12 Hz), 4.64 (d, ABq, 2H, –
CCH2OR–, J = 12 Hz), 5.25 (m, 1H, –CHOR), 5.46 (s, 1H, –CHPh), 7.31–7.47 (m, 5H,
Ar).
4-(ε-Caprolactone) 2,2-bis(phenyldioxymethyl)propionate
6 (2.55 g, 0.0096 mol) was dissolved in 30 mL of CHCl3 and added dropwise to a
solution of 3-chloroperoxybenzoic acid (60%) (3.16 g, 0.018 mol) in CHCl3 (300 mL).
The mixture was stirred for 24 h and then filtered through Celite. The yellow solution
was washed with 2M NaHCO3 (2X) and NaCl solution (2X) and concentrated. The
extracted product was purified by column chromatography (silica gel using hexane/ethyl
acetate as the eluant) followed by crystallization from ethanol to give a white crystalline
powder in 51% yield. 1H-NMR (CDCl3) δ = 1.03 (s, 3H, –CH3), 1.85–2.18 (m, 4H, –
CHCH2–), 2.39–2.49 (m, 1H, –CH2COO–), 2.89–3.00 (m, 1H, –CH2COO–), 3.66 (d,
ABq, 2H, –CCH2OR–, J = 12 Hz), 4.11 (m, 1H, –COOCH2–), 4.40–4.50 (m, 1H, –
COOCH2–), 4.62 (d, ABq, 2H, –CCH2OR–, J = 12 Hz), 5.21 (m, 1H, –CHOR), 5.45 (s,
1H, –CHPh), 7.31–7.47 (m, 5H, Ar).
13
C-NMR (CDCl3) δ 174.9, 173.0, 138.0, 129.0,
128.2, 125.8, 101.6, 73.9, 73.7, 73.6, 73.6, 70.4, 63.5, 42.7, 33.7, 28.3, 27.4, 17.6. Anal.
Calcd. for C, 64.66; H, 6.63. Found: C, 64.54; H, 6.73.
4-(ε-Caprolactone) 2,2-bis(hydroxymethyl)propionate
4-(ε-Caprolactone) 2,2-bis(phenyldioxymethyl)propionate was deprotected by catalytic
hydrogenolysis
using
Pd/C
(10
%).
3g
of
4-(ε-Caprolactone)
2,2-
bis(phenyldioxymethyl)propionate was dissolved in 10 mL of THF and diluted with
EtaOAC 100(mL) before 1.0 g of Pd/C (10 %) was added. The apparatus for catalytic
hydrogenolysis was evacuated and filled with H2(g). The reaction mixture was stirred for
24h, and the Pd/C was removed by filtration and the reaction concentrated. 1H-NMR
(CDCl3) δ = 1.02 (s, 3H, –CH3), 1.93–2.07 (m, 4H, –CHCH2–), 2.40–2.49 (m, 1H, –
CH2COO–), 2.89–2.95 (m, 1H, –CH2COO–), 3.66- 4.07 (2m, 2H, –CCH2OH–), (m, 1H,
–COOCH2–), 4.12- 4.22 (m, 1H, –COOCH2–), 5.15-5.16 (m, 1H, –CHOR).
4-(ε-Caprolactone) 2,2-bis(dioxymethyl ferrocenyl)propionate
4-(ε-Caprolactone) 2,2-bis(hydroxymethyl)propionate (2.00g, 0.008mol) and ferrocene
carboxylic acid (4.02g, 0.017mol) were dissolved in 40mL of THF. To this solution,
4.57g (0.017mol) of triphenylphosphine was added and DIAD (3.53g, 0.017mol) was
added dropwise over a 30 min. period and allowed to react overnight. The reaction was
concentrated and the product isolated by column chromatography (ethyl acetate/hexane).
1
H-NMR (CDCl3) δ = 1.28 (s, 3H, –CH3), 2.03–2.20 (m, 4H, –CHCH2–), 2.89–2.90 (m,
1H, –CH2COO–), 2.89–2.95 (m, 1H, –CH2COO–), 4.11- 4.47 (2m, 2H, –CCH2OR–),
4.23 (s, 5H, Cp), 4.44 (d, 2H, Cp), 4.79-4.08 (d, 2H, Cp), 5.23-5.24 (m, 1H, –CHOR).
&DSURODFWRQHG10
To a 3-neck flask equipped with mechanical stirrer and a nitrogen purge, was added 3chloroperoxybenzoic (56.5 g, 0.19 mole) acid dissolved in chloroform (180 mL).
Cyclohexanone- d10
( 19.3 g, 0.18mole) dissolved in 40 mL chloroform was added
dropwise with vigorous stirring while maintaining the reaction temperature below 50 C
with slight cooling. After the reaction subsided the mixture was stirred at 50 C for 45
minutes. The mixture was then cooled to room temperature, white solids were filtered
and washed with cold chloroform. The combined filtrate was extracted with dilute
aqueous sodium bicarbonate followed by water. The organic layer was separated, dried
with sodium sulfate and concentrated in vacuo. The product was isolated in 66% yield as
clear liquid by distillation: bp 85 C, 3.4 Torr.