The use of Piers-Rubinsztajn conditions for the placement of triarylamines pendant to silicone polymers

Article abstract of DOI:10.1021/ma202041u

The use of Piers-Rubinsztajn conditions was explored for the synthesis of silicone polymers bearing pendant triarylamine functionality. We have found that up to 60% of the hydride groups of a silicone copolymer can be successfully substituted with a triarylamine moiety, without metathesis or redistribution of the silicone. The resulting polymers are hydrolytically stable. The functionalization procedure is straightforward, conducted under ambient conditions with a simple one-step work-up, and avoids the use of a metal-based catalyst. The resulting phenylated triarylamine-silicone hybrid polymer was characterized by optical absorption and fluorescence spectroscopy, CV, and differential scanning calorimetry. The hybrids maintain the physical appearance of a silicone polymer while adopting the photophysical and electrochemical characteristics of the triarylamine.

Full text of DOI:10.1021/ma202041u

Article
pubs.acs.org/Macromolecules
The Use of Piers−Rubinsztajn Conditions for the Placement of
Triarylamines Pendant to Silicone Polymers
Michael J. Gretton,† Brett A. Kamino,† Michael A. Brook,§ and Timothy P. Bender*,†,‡
†Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario, Canada
M5S 3E5
‡Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, Canada M5S 3H6
§Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St., Hamilton, Ontario, Canada L8S 4M1
S
* Supporting Information
ABSTRACT: The use of Piers−Rubinsztajn conditions was
explored for the synthesis of silicone polymers bearing pendant
triarylamine functionality. We have found that up to 60% of the
hydride groups of a silicone copolymer can be successfully
substituted with a triarylamine moiety, without metathesis or
redistribution of the silicone. The resulting polymers are
hydrolytically stable. The functionalization procedure is
straightforward, conducted under ambient conditions with a
simple one-step work-up, and avoids the use of a metal-based
catalyst. The resulting phenylated triarylamine−silicone hybrid
polymer was characterized by optical absorption and fluores-
cence spectroscopy, CV, and differential scanning calorimetry.
The hybrids maintain the physical appearance of a silicone
polymer while adopting the photophysical and electrochemical characteristics of the triarylamine.
CHCl3, CH3CN, THF, and DMF. The latter group noted the
speed and versatility of this methodology when both nonlinear
optical (NLO) and hole-transporting moieties were grafted to
the same chain.9 The incorporation of a triarylamine pendant to
poly(methylhydrosiloxane) was also found to produce a
silicone−triarylamine hybrid polymer with hole-transporting
properties comparable to the respective small molecule.28
Similar results were observed for polymers containing the
related carbazole group.9 Another method for the formation of
pendant triarylamine silicone polymers involves the use of
organometallic reagents, such as Grignard or halolithium
triarylamines, which are reacted with chloro- or alkoxysilanes;
however, these reactions are known to create byproducts.29 It is
presumed that if the metal species remains in the final polymer,
it will result in charge trapping, unbalanced carrier transport, or
nonradiative recombination, all of which are generally
detrimental to performance of organic electronic devices.30−32
Regardless of the method, there is a clear and demonstrated
desire to form silicone polymers with pendant triarylamine
functionality, and the utility of such polymers has been
demonstrated.
INTRODUCTION
■
Triarylamines are a well-known class of organic hole-trans-
porting materials (HTMs).1,2 Often, as small molecules, HTMs
are incorporated in organic electronic devices as thin films
using vacuum deposition techniques. However, solution
processing methods, such as inkjet printing, hold particular
advantages in the production of uniform layers across large
areas.3 Incorporating a triarylamine into the structure of a
flexible polymer is recognized to provide better film-forming
properties and allows for facile, cost-effective solution
processing methods to be used.4,5 For example, a polymeric
version of a fluorinated triphenyldiamine, made by polymer-
ization of a constituent vinyl group, showed similar or better
performance in an organic light-emitting diode (OLED) than
the small-molecule analogue.6 In addition to the direct
polymerization of vinyl-containing triarylamines,7,8 a postpoly-
merization grafting technique has been used to form triaryl-
amine-containing polymers.9 Most commonly this technique
has involved hydrosilylation of vinyl,10−13 allyl,12−23 or
ethynyl24,25 groups attached to a triarylamine or carbazole
derivative with silanes (Si−H) using hexachloroplatinate(IV)
hydrate or other Pt- or Ru-based catalysts.3,25,26,28 For example,
Belfield et al. and the groups of Moerner and Siegel and co-
workers have attached N-allylcarbazoles and an allyl-function-
alized triarylamine, respectively, to poly(methylhydro)siloxane
using hydrosilylation to synthesize new photorefractive
polymers.28,9,27 The former group found the resulting polymer
to be soluble in a broad range of solvents including CH2Cl2,
Recently, we have demonstrated the applicability of Piers−
Rubinsztajn (P−R) conditions33−40 in the functionalization of
triarylamines with simple and discrete oligosilicones.41 The
Received: September 7, 2011
Revised: November 25, 2011
Published: December 28, 2011
© 2011 American Chemical Society
723
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728

Macromolecules
Article
Scheme 1. Synthesis of Triarylamine 2 Followed by Grafting onto Silicone Polymer under Piers−Rubinsztajn Conditions To
Produce Silicone−Triarylamine Hybrid Polymer 3
procedure uses the strong Lewis acid tris(pentafluorophenyl)-
borane (BCF) to effect the reaction under mild conditions. It
was previously known that BCF selectively activates Si−H
bonds to coupling with Si−OH,39 Si−O−alkyl,40,42 and aryl−
OH43 groups.44−46 We have shown that BCF can also do the
same in the presence of a Lewis basic triarylamine substrate
containing arylmethoxy groups, the result of which is the
formation of an Si−O−triarylamine bond with the elimination
of CH4 as a byproduct. Given the utility outlined above for
silicone−triarylamine hybrid polymers, it was of interest to see
whether P−R conditions can be extended past the use of simple
small discrete silicone fragments and be applicable to the
preparation of silicone−triarylamine hybrid polymers whereby
the triarylamine is in a position pendant to the polymer main
chain. Therefore, in this article, we describe the application of
P−R conditions to install a model triarylamine pendant to a
siloxane copolymer and compare the physical properties of the
triarylamine moiety before and after grafting to the silicone.
hydride functionality available for reaction. By comparison,
poly(dimethylsiloxane) is expected to adopt a coiled con-
formation in toluene solution owing to its unfavorable χ-
parameter (0.802).51 If we extend this to the structurally related
methyl−hydride/dimethylsiloxane copolymer, the hydride
groups would potentially be unavailable for reaction due to a
likely coiled conformation in solution.
Initial reaction of HPM-502 with 1.1 equiv of triarylamine 2
(relative to hydride) at a solution concentration of 25 wt %
resulted in incorporation of only 53% of the triarylamine into
the polymer, leaving 40% of the original hydrides (Si−H)
remaining in the polymer (i.e., 60% reacted, run 1, Table 1).
Table 1. Summary of Reactions of Silicone Copolymer with
Triarylamine 2 under Piers−Rubinsztajn Conditions
mol equiv
triarylamine
( 0.02)
temp wt % solids
% conv of
triarylamine
% conv of
Si−H
run (°C)
( 1%)
1
rt
rt
rt
rt
55
80
rt
rt
rt
rt
rt
rt
25
25
20
15
25
25
25
25
25
25
25
25
1.1
53
69
60
62
54
39
60
59
48
53
53
54
56
56
2
0.9
RESULTS AND DISCUSSION
■
3
0.9
60
The synthetic route used to construct the model triarylamine 2
is outlined in Scheme 1. The synthesis of 2 was accomplished
by reaction of 3,4-dimethylaniline with 4-bromoanisole to form
the intermediate diarylamine (1) under standard Buchwald−
Hartwig coupling conditions.47,48 Further reaction of 1 with 4-
bromobiphenyl, again under standard conditions, gave the
model triarylamine 2 in good yield and purity. Triarylamine 2
contains the reactive arylmethoxy unit that is necessary for
participation in the P−R coupling reaction. It also contains
both 3,4-dimethylphenyl and biphenyl molecular fragments.
These were chosen because of their presence in the triarylamine
bis(3,4-dimethylphenyl)-(1-biphenyl)amine, whose electronic
properties, including oxidation potential and charge carrier
mobility, are known.49
4
0.9
44
5
0.9
66
6
0.9
66
7
0.6
82
8
0.55
0.55
0.55
0.55
0.55
100
100
100
100
100
9
10
11
12
The percent incorporation of the triarylamine in the polymer
was calculated based on comparison of areas of the resolved
polymer and triarylamine peaks in a GPC chromatogram
(extracted from a PDA chromatogram at a wavelength specific
for the triarylamine chromophore, 330 nm) with the
assumption of similar molar absorptivities of free and pendant
triarylamine moiety. Chromatograms of the product 3 and
HPM-502 are given in the Supporting Information (Figure S1).
The initial polymer, HPM-502, had an apparent molecular
weight of Mn = 1390 (PDI = 2.39, relative to polystyrene
standards). After functionalization to given polymer 3, a
moderate increase to Mn = 2700 (PDI = 2.73) was seen. The
Gaussian appearance of the polymer traces suggest that no
metathesis or other redistribution of the silicone occurred. The
A silicone polymer was then selected for reaction with the
triarylamine 2. The silicone selected was HPM-502 of Gelest
Inc., a silicone copolymer of moderate viscosity containing both
methyl−hydride (45−50%) and methyl−phenyl units with a
hydride terminus. A silicone polymer containing phenyl units
was chosen to ensure compatibility/cosolubility of the silicone
polymer and the triarylamine at ambient temperatures in
toluene (the solvent of choice for P−R reactions on
triarylamines). Furthermore, qualitatively the presence of
phenyl units should ensure the polymer adopts a largely
extended uncoiled conformation in solution,50 thus making the
724
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728

Macromolecules
Article
presence of residual Si−H groups was confirmed by FTIR
spectroscopy showing the distinctive Si−H stretch around 2160
cm−1,27 as illustrated in Figure 1. Decreasing the amount of
adsorbed on the alumina surface or present in the toluene.
These conditions were subsequently replicated four times with
equivalent results (runs 9−12, Table 1).
Having polymer 3 free of residual triarylamine in hand, its
basic physical properties were determined. The electrochemical
properties of 2 and 3 were compared by cyclic voltammetry, the
results of which are illustrated in Figure 2. In each case the
Figure 1. Representative FTIR transmission spectra of starting
siloxane copolymer HPM-502 (bottom, black) and polymer 3 (top,
gray).
Figure 2. Cyclic voltammogram of triarylamine 2 (red) and polymer 3
(blue); second cycles only are shown, corrected to the known
reference value for decamethylferrocene standard (−0.012 V).
triarylamine 2 used to 0.9 equiv resulted in a similar result: 60%
of the hydride functionality was converted (run 2, Table 1).
Continued use of 0.9 equiv of triarylamine 2, but decreasing the
concentration of the reaction solution from 25 to 20 wt % and
then 15 wt %, resulted in 54 and 39% of the hydride
functionality reacting, respectively (runs 3 and 4, Table 1).
Again, by maintaining 0.9 equiv of triarylamine 2 but increasing
the temperature to 55 and 80 °C, respectively, and while
maintaining a concentration of 25 wt % resulted in ∼60% of the
hydride functionality reacting (runs 5 and 6, Table 1). The
conclusions from these initial experiments are that there is a
ceiling above which no further reaction of the hydride occurs.
The ceiling occurs at ∼60% conversion and is independent of
temperature and the amount of triarylamine 2 present and
decreases on decreasing the concentration of the reaction. We
concluded that the cause of this observation must be steric in
nature whereby the reaction is hindered once a neighboring
hydride, or a series of neighbors, has been substituted with the
triarylamine. This occurs even though toluene is a good solvent
for the base silicone, the triarylamine, and, presumably, a
silicone−triarylamine hybrid polymer.
voltammograms were acquired using the same technique as we
have previously published which involves the use of an internal
standard of decamethylferrocene.53 The reversible oxidation of
the triarylamine moiety pendant to the silicone copolymer
occurs at higher half-wave potential (967 mV) than that of
parent triarylamine (807 mV), behavior similar to that
previously observed for oligosilicone-functionalized triaryl-
amines.47
DSC experiments were performed on triarylamine 2 and
polymer 3. The samples were first heated to ∼275 °C under an
inert atmosphere followed by flash freezing to ∼−75 °C. For
polymer 3 on second heating a glass transition temperature
(Tg) was found at ∼−60 °C and a second found at ∼20 °C
(Figure 3). The first Tg is the range expected for a silicone
Polymer 3 is a highly viscous oil or glassy solid in appearance
even when it contains residual triarylamine. Its physical state
makes removal of residual triarylamine problematic using
techniques such as selective precipitation, solvent extraction, or
chromatography on silica or alumina. Therefore, we preferred
to develop reaction conditions under which the triarylamine is
quantitatively incorporated into the hybrid polymer 3. Given
the observed ceiling of 60% conversion of hydride groups, we
initially tried reacting 0.6 equiv of triarylamine 2 (run 7, Table
1). However, we observed only 82% conversion of the
triarylamine. A small reduction to 0.55 equiv of triarylamine
resulted in its complete incorporation into the polymer (run 8,
Table 1). The only purification that was necessary was removal
of the BCF catalyst by treatment of the reaction mixture with a
small amount of alumina for a short period of time. Filtration
followed by removal of the toluene by rotary evaporation gave
the final polymer 3. We found that prolonged stirring of the
solution (overnight) in the presence of alumina resulted in the
partial hydrolysis of the triarylamine from the silicone polymer,
presumably due to the presence of trace amounts of water
Figure 3. DSC traces for polymer 3 (black) and parent triarylamine 2
(gray). DSC traces collected on second heating.
polymer while the second is in the range expected for a pure
triarylamine.53 Indeed, DSC confirms that the Tg for triaryl-
amine 2 to be ∼25 °C (Figure 3). A small melt transition is also
observed for polymer 3 at ∼62 °C. While melt transition is well
below that observed for pure triarylamine 2 (∼100 °C), its
presence and the presence of a Tg in the range expected for
725
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728

Macromolecules
Article
pure triarylamine would suggest the possibility of aggregation of
the triarylamine moieties in the solid state.
In order to examine whether aggregation of the triarylamine
moieties occurs in polymer 3, UV−vis absorbance and
fluorescence emission spectroscopy were conducted on triaryl-
amine 2 and polymer 3 (Figure 4). In each case the
compared to the same treated with acidic standard alumina over
a 2 day period in solution (conditions mentioned above which
results in hydrolysis). The thin film exposed to air showed no
change in the FTIR spectrum between 4000 and 4500 cm−1
over time, whereas the alumina-treated sample developed an
absorbance band at 3546 cm−1, which is attributable to the
stretch of an Si−OH bond formed on hydrolysis (Supporting
Information, Figure S2). The absence of a 3546 cm−1 stretch for
the thin film indicates polymer 3 is hydrolytically stable over
the period of 1 month.
CONCLUSION
■
In conclusion, Piers−Rubinsztajn conditions were found to be
useful in functionalizing a phenylmethyl−methylhydride
silicone copolymer with a triarylamine leading to the formation
of a silicone−triarylamine hybrid polymer. The reaction
requires very low concentration of the BCF catalyst; work-up
is clean and straightforward. No redistribution or metathesis of
the silicone polymer was observed, and the polymer showed
excellent hydrolytic stability in air. We did observe a ceiling
whereby only 60% of the hydride functionality present in the
silicone polymer could be reacted under these conditions. The
hybrid silicone−triarylamine hybrid polymer displayed com-
parable electronic and optical properties to the parent
triarylamine as determined from CV and optical absorption
and fluorescence spectroscopy. We can therefore conclude that
Piers−Rubinsztajn conditions are suitable to prepare polymers
of this class that have a demonstrated utility in the field where
we do not believe the residual hydride functionality would be a
problem.
Figure 4. Overlay of UV−vis absorption and fluorescence emission
spectra for triarylamine (2, red) and polymer 3 in both solution
(dashed blue) and solid state (dash-dotted blue).
characteristic absorption of the triarylamine was seen (334
nm for triarylamine 2 and 333 nm for polymer 3). Similarly,
ordinary fluorescence spectra were observed with Stokes shifts
of 73 and 71 nm for 2 and 3, respectively, in toluene solution. A
fluorescence spectrum obtained on a solid-state sample of
polymer 3 showed a nearly identical emission spectrum to the
solution sample, albeit with a slightly larger Stokes shift. In an
attempt to force aggregation in solution, we compared the
fluorescence spectrum of polymer 3 in pure toluene to that in a
series of solvent mixtures with increasing proportions of
hexamethyldisiloxane (HMDS, a nonsolvent for the triaryl-
amine). As can be seen in Figure 5, the emission maximum
EXPERIMENTAL SECTION
■
Materials and Syntheses. Toluene was purified using a PureSolv
solvent purification system prior to use. Tris(pentafluorophenyl)-
borane, montmorillonite K10 clay, and tetrabutylammonium per-
chlorate were obtained from Sigma-Aldrich and used without further
purification. HPM-502 (methylhydrosiloxane−phenylmethylsiloxane
copolymer, 45−50 mol % MeHSiO, hydride-terminated) was
purchased from Gelest Inc. (Morrisville, PA) and used without further
purification. All other solvents were 99% or higher purity from
Caledon Laboratories Ltd. (Brockville, ON, Canada), as was
chromatographic silica gel 60 (50−100 μm). Deuterated chloroform
(CHCl3) was purchased from Cambridge Isotopes and used without
further purification.
Characterization Techniques. Melting points are uncorrected.
Triarylamine syntheses were monitored by TLC on SilicaPlate 250 μm
thick silica gel with F-254 indicator, using 1:1 (v/v) cyclo-
hexane:toluene as eluent and visualizing using 254 and 365 nm UV
light. Polymer functionalization was monitored by gel permeation
chromatography (GPC) using Waters Styragel HR 4E THF and
Styragel HR 5W THF columns in series, 5 μm particle size, THF
eluent at a flow rate of 1.0 mL/min at 30 °C; a photodiode array
(254−800 nm) in “MaxPlot” mode was used for detection.
Chromatograms were uncorrected by individual compounds’ molar
absorptivities. All NMR spectra were collected on a Varian Mercury
400 spectrometer in CDCl3. Chemical shifts are reported in parts per
million referenced relative to tetramethylsilane internal standard.
Coupling constants (J) are reported in hertz. High-resolution mass
spectroscopy was taken with an AB/Sciex QStar mass spectrometer.
Samples were introduced with an ESI source in solution (50:50
methanol and water) via an HPLC pump. Cyclic voltammetry (CV)
was performed with a Bioanalytical Systems C3 electrochemical cell
setup. The working electrode was a 1 mm platinum disk with a
platinum wire used as a counter electrode. The reference electrode was
Ag/AgCl saturated salt solution. All electrochemistry was done in
“Spectro” grade dichloromethane from Caledon Laboratories with
Figure 5. Overlay of fluorescence emission spectra of polymer (3) in
toluene solution (green) and 99:1 (v/v) hexamethyldisiloxane:toluene
(blue).
underwent a small hypsochromic shift, but no additional
shoulders or structure was seen in the spectrum. The rather
ordinary photophysical behavior of polymer 3 in both solution
and solid state indicates that if aggregation of the triarylamine
does occur (as suggested by the DSC thermogram), it does not
result in energy transfer on excitation and emission from an
excimer or aggregate.54,55 Finally, the hydrolytic stability of 3
was evaluated using FTIR spectroscopy on a thin film of
polymer 3 exposed to air at rt over a 1 month period. This was
726
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728

Macromolecules
Article
(Bu)4NClO4 as a supporting electrolyte. Decamethylferrocene was
added to the solutions as an internal reference. All DSC half-wave
potentials are reported from the second scan and corrected by the
internal reference (−0.012 V vs Ag/AgCl2).56 Fourier transform
infrared (FTIR) spectra were recorded on KBr plates using a Perkin-
Elmer Spectrum 100 spectrometer from 4000 to 400 cm−1. Solution
spectroscopy was performed in quartz cuvettes with 1.0 cm path
length. Optical absorption measurements were conducted using a
Perkin-Elmer Lambda 1050 UV/vis/NIR spectrometer. Fluorescence
measurements were conducted using a Perkin-Elmer FS55 spectro-
fluorometer. Polymer films were drop-cast onto quartz disks and dried
overnight at 80 °C under vacuum before fluorescence measurements
were taken. Spectra were processed using Spekwin 32 (all types),
Perkin-Elmer UV Winlab (UV−vis), or FL WinLab (fluorescence)
software. Differential scanning calorimetry was performed with a TA
Instruments 2920 DSC with a refrigerated cooling system, using Al
hermetic pans. Tests were performed under a blanket of nitrogen.
N-(3,4-Dimethylphenyl)-4-anisidine (1). The synthesis proce-
dure is similar to that previously reported,53 using Buchwald−Hartwig
reaction conditions, washing crude product with 1.0 M HCl(aq) and
NaHCO3, and substituting silica gel and montmorillonite K10 clay for
alumina and acidic benonite clay. Recrystallization from n-heptane
ASSOCIATED CONTENT
■
S
* Supporting Information
GPC data for silicone HPM-502 and polymer 3; H and 13C
NMR for compounds 1 and 2 and polymer 3. This material is
available free of charge via the Internet at http://pubs.acs.org.
1
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: tim.bender@utoronto.ca.
ACKNOWLEDGMENTS
■
We thank the Natural Sciences and Engineering Research
Council of Canada (NSERC) for their support through the
Discovery Grant Program (T.P.B.) and an NSERC-CREATE
fellowship (M.J.G.) as well as the Ontario Graduate Scholarship
program and the Bert Wasmund Fellowship (University of
Toronto) for assistance (B.A.K.). Mohsen Soleimani Kheibari
and Prof. Mitchell A. Winnik (Department of Chemistry,
University of Toronto) are acknowledged for assistance in
acquiring the DSC data.
1
yielded white needles (46%); mp 99−101 °C. H NMR (400 MHz,
CDCl3): δ 7.02 (2H, d, J = 8.9 Hz), 6.98 (1H, d, J = 8.2 Hz), 6.84 (2H,
d, J = 8.9 Hz), 6.75 (1H, d, J = 2.2 Hz), 6.70 (1H, dd, J1 = 8.8 Hz, J2 =
2.4 Hz), 5.34 (1H, br s), 3.79 (3H, s), 2.20 (3H, s), 2.19 (3H, s). 13C
NMR (100 MHz, CDCl3): δ = 155.3, 143.4, 137.3, 137.3, 130.7, 127.9,
121.5, 118.6, 115.0, 114.6, 55.1, 20.0, 19.0. HRMS (ESI, [M + H]+)
calcd for C15H18NO m/z = 228.1388; found 228.1377.
REFERENCES
■
(1) Shirota, Y.; Kageyama, H. Chem. Rev. 2007, 107, 953−1010.
(2) Klenkler, R. A.; Voloshin, G. J. Phys. Chem. C 2011, 115 (34),
16777−16781.
(3) Igarashi, T. EP 2 083 013 (A1). Filed Oct 31, 2007.
(4) Bellmann, E.; Jabbour, G. E.; Grubbs, R. H.; Peyghambarian, N.
Chem. Mater. 2000, 12, 1349−1353.
N-(3,4-Dimethylphenyl)-N-(4-methoxyphenyl)biphenyl-4-
amine (2). The synthesis procedure is similar to that previously
reported,57 using a bis(dibenzylideneacetone)palladium(0) and tri-tert-
butylphosphine catalyst system and using silica gel with montmor-
illonite K10 clay in purification. Excess 4-bromobiphenyl was distilled
off at elevated temperature. Product was recrystallized from n-heptane
as fluffy white powder (48%); mp 134−136 °C. 1H NMR (400 MHz,
CDCl3): δ 7.60−7.56 (2H, m), 7.47−7.39 (4H, m), 7.30 (1H, t, J =
7.4 Hz), 7.12 (2H, d, J = 8.8 Hz), 7.05 (3H, d, J = 8.8 Hz), 6.95 (1H,
d, J = 2.1 Hz), 6.91−6.84 (3H, m), 3.83 (3H, s), 2.25 (3H, s), 2.21
(3H, s). 13C NMR (100 MHz): δ 156.0, 147.9, 145.6, 140.8, 137.5,
133.4, 131.1, 130.3, 128.7, 127.5, 127.0, 126.5, 125.5, 121.8, 121.6,
114.7, 55.5. 19.9, 19.1. HRMS (ESI, [M + H]+) calcd for C27H26NO
m/z 380.2014; found 379.2025. UV−vis (nm) 311.1, 333.2.
Fluorescence (nm) 406.2; CV oxidation (mV) 795 vs Ag/AgCl.
Poly[methyl-N-(3,4-dimethylphenyl)-N-(4-biphenyl)-N-(4-
phenyloxy)siloxane-co-phenylmethylsiloxane-co-methylhy-
drosiloxane] (3). N-4-Anisyl-N-3′,4′-xylyl-4-biphenylamine (600 mg,
1.53 mmol), methylhydrosiloxane−phenylmethylsiloxane copolymer
(5) Nuyken, O.; Jungermann, S.; Wiederhirn, V.; Bacher, E.;
Meerholz, K. Monatsh. Chem. 2006, 137, 811−824.
(6) Shaheen, S. E.; Jabbour, G. E.; Kippelen, B.; Peyghambarian, N.;
Anderson, J. D.; Marder, S. R.; Armstrong, N. R.; Bellmann, E.;
Grubbs, R. H. Appl. Phys. Lett. 1999, 74 (21), 3212−3214.
(7) Lindner, S. M.; Thelakkat, M. Macromolecules 2004, 37 (24),
8832−8835.
(8) Sommer, M.; Lindner, S. M.; Thelakkat, M. Adv. Funct. Mater.
2007, 17 (9), 1493−1500.
(9) Bratcher, M. S.; DeClue, M. S.; Grunnet-Jepsen, A.; Wright, D.;
Smith, B. R.; Moerner, W. E.; Siegel, J. S. J. Am. Chem. Soc. 1998, 120,
9680−9681.
(10) Ushakov, N. V.; Pritula, N. A.; Rebrov, A. I. Russ. Chem. Bull.
1993, 42 (8), 1372−1376.
(11) Chen, K.-B.; Chang, Y.-P.; Yang, S.-H.; Hsu, C.-S. Thin Solid
Films 2006, 514, 103−109.
(12) Witker, D. Suzuki, T. WO2009/089031 (A1). Filed Jan 8, 2009.
(13) Mochizuki, A.; Kondo, T.; Li, S.; Froelich, J., D.; Chae, H.-S.
WO2010/045263 (A3). Filed Oct 13, 2009.
(458 mg, 2.78
0.08 mmol of Si−H), and 3.06 mL of anhydrous
(14) Strohriegl, P. Makromol. Chem., Rapid Commun. 1986, 7, 771−
toluene were loaded into a 4 dram vial with stir bar. The vial was
heated to the reaction temperature if not rt. 115 μL of 0.025 g/mL
tris(pentafluorophenyl)borane in anhydrous toluene was then injected,
resulting in vigorous bubbling within seconds to <4 min after catalyst
addition. Catalyst loading was either 0.25 or 0.50 mol % relative to
triarylamine R−O−Ar groups. Caution: an exotherm and flammable gas
evolution are associated with this reaction, which should be accounted for in
larger scale experiments. Stirring was continued for 20−30 min after
bubbling was no longer visible, after which 600 mg of basic standard
alumina was added, stirred for 20−30 s, and the mixture filtered
through 0.22 μm PTFE. Overnight stirring with silica or alumina, in
ambient conditions or at elevated temperature, was found to result in
775.
(15) Bisberg, J.; Cumming, W. J.; Gaudiana, R. A.; Hutchinson, K.
D.; Ingwall, R. T.; Kolb, E. S.; Mehta, P. G.; Minns, R. A.; Petersen, C.
P. Macromolecules 1995, 28, 386−389.
(16) Chun, H.; Moon, I. K.; Shin, D.-H.; Kim, N. Chem. Mater. 2001,
13, 2813−2817.
(17) Lee, S. H.; Jahng, W. S.; Park, K. H.; Kim, N.; Joo, W.-J.; Choi,
D. H. Macromol. Res. 2003, 11 (6), 431−436.
(18) Moon, I. K.; Oh, J.-W.; Kim, N. J. Photochem. Photobiol., A 2008,
194, 327−332.
(19) Moon, I. K.; Oh, J.-W.; Kim, N. J. Photochem. Photobiol., A 2008,
194, 351−355.
1
more extensive decomposition and so was avoided. H NMR of the
(20) Moon, I. K.; Choi, C.-S.; Kim, N. J. Photochem. Photobiol., A
2009, 202, 57−62.
purified product showed no detectable toluene after drying overnight
at 80 °C under vacuum. UV−vis (nm) 310.7, 331.4. Fluorescence
(nm) 402.3 (toluene solution), 406.0 (film). CV oxidation (mV) 891
vs Ag/AgCl. Tg (°C) 27.8 (second heating curve in DSC).
(21) Yang, X.; Froehlich, J. D.; Chae, H. S.; Li, S.; Mochizuki, A.;
Jabbour, G. E. Adv. Funct. Mater. 2009, 19, 2623−2629.
(22) Lin, Y. C.; Chen, C. T. Org. Lett. 2009, 11 (21), 4858−4861.
727
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728

Macromolecules
Article
(23) Moon, I. K.; Oh, J.-W.; Lee, C. K.; Kim, N. Opt. Mater. 2010, 32,
436−442.
(52) Bratcher, M. S.; DeClue, M. S.; Grunnet-Jepsen, A.; Wright, D.;
Smith, B. R.; Moerner, W. E.; Siegel, J.S. J. Am. Chem. Soc. 1998, 120,
9680−9681.
(24) Lee, T.; Song, K. H.; Jung, I.; Kang, Y.; Lee, S.-H.; Kang, S. O.;
Ko, J. J. Organomet. Chem. 2006, 691, 1887−1896.
(25) Lu, P.; Lam, J. W. Y.; Liu, J.; Jim, C. K. W.; Yuan, W.; Chan, C.
Y. K.; Xie, N.; Hu, Q.; Cheuk, K. K. L.; Tang, B. Z. Macromolecules
2011, 44 (15), 5977−5986.
(53) Bender, T. P.; Graham, J. F.; Duff, J. M. Chem. Mater. 2001, 13,
4105−4111.
(54) Halkyard, C. E.; Rampey, M. E.; Kloppenburg, L.; Studer-
Martinez, S. L.; Bunz, U. H. F. Macromolecules 1998, 31 (25), 8655−
8659.
(55) Prieto, I.; Teetsov, J.; Fox, M. A.; Vanden Bout, D. A.; Bard, A. J.
J. Phys. Chem. A 2001, 105, 520−523.
(56) Noviandri, I.; Brown, K. N.; Fleming, D. S.; Gulyas, P. T.; Lay,
P. A.; Masters, A. F.; Phillips, L. J. Phys. Chem. B 1999, 103, 6713−
6722.
́
(26) Waehner, J.; Marciniec, B.; Pawluc, P. Eur. J. Org. Chem. 2007,
2975−2980 . Synthetic routesother than hydrosilylation continue to be
used, such as this Ru-catalyzedsilylative coupling, but based on a
literature search, this techniqueis still less common than hydro-
silylation.
(27) Belfield, K. D.; Chinna, C.; Najjar, O. Macromolecules 1998, 31,
(57) Monguchi, Y.; Kitamoto, K.; Ikawa, T.; Maegawa, T.; Sajiki, H.
Adv. Synth. Catal. 2008, 350, 2767−2777.
2918−2924.
(28) Wright, D.; Gubler, U.; Moerner, W. E.; DeClue, M. S.; Siegel, J.
S. J. Phys. Chem. B 2003, 107, 4732−4737.
(29) Tachikawa, M. Takei, K. US 5,994,573. Nov 30, 1999.
(30) Kang, S. H.; Crisp, T.; Kymissis, I.; Bulovíc, V. Appl. Phys. Lett.
2004, 85 (20), 4666−4668.
(31) Choi, J.-S.; Cho, Y. S.; Yook, J. Y.; Suh, D. H. Polym. Adv.
Technol. 2010, 21, 780−783.
(32) Kuik, M.; Nicolai, H. T.; Lenes, M.; Wetzelaer, G.-J. A. H.; Lu,
M. T.; Blom, P. W. M. Appl. Phys. Lett. 2011, 98, 093301:1−3. Trap
creationcan also occur by evaporationor diffusion of metal contact
material in, e.g., field effect transistors.See, for example: Koehler, M.;
Biaggio, I.; da Luz, M. G. E. Phys. Rev. 2008, 78, 153312:1−4.
(33) Parks, D. J.; Piers, W. E. J. Am. Chem. Soc. 1996, 118, 9440−
9441.
(34) Blackwell, J. M.; Foster, K. L.; Beck, V. H.; Piers, W. E. J. Org.
Chem. 1999, 64, 4887−4892.
(35) Parks, D. J.; Blackwell, J. M.; Piers, W. E. J. Org. Chem. 2000, 65,
3090−3098.
(36) Gevorgyan, V.; Rubin, M.; Benson, S.; Liu, J.-X.; Yamamoto, Y.
J. Org. Chem. 2000, 65 (19), 6179−6186.
(37) Gevorgyan, V.; Rubin, M.; Liu, J.-X.; Yamamoto, Y. J. Org. Chem.
2001, 66, 1672−1675.
(38) Blackwell, J. M.; Morrison, D. J.; Piers, W. E. Tetrahedron 2002,
58, 8247−8254.
(39) Piers, W. E. The chemistry of perfluoroaryl boranes. In Advances
in Organometallic Chemistry; West, R., Hill, A. F., Eds.; Elsevier
Academic Press: San Diego, 2005; Vol. 52, pp 1−46.
(40) Chojnowski, J.; Rubinsztajn, S.; Cella, J. A.; Fortuniak, W.;
Cypryk, M.; Kurjata, J.; Kazmierski, K. Organometallics 2005, 24,
6077−6084.
(41) Kamino, B. A.; Grande, J. B.; Brook, M. A.; Bender, T. P. Org.
Lett. 2011, 13 (1), 154−157.
(42) Thompson, D. B.; Brook, M. A. J. Am. Chem. Soc. 2008, 130,
32−33.
(43) Cella, J.; Rubinsztajn, S. Macromolecules 2008, 41 (19), 6965−
6971.
(44) Rubinsztajn, S.; Cella, J. A. Macromolecules 2005, 38 (4), 1061−
1063.
(45) Chojnowski, J.; Fortuniak, W.; Kurjata, J.; Rubinsztajn, S.; Cella,
J. A. Macromolecules 2006, 39, 3802−3807.
(46) Brook, M. A.; Grande, J. B.; Ganachaud, F. Adv. Polym. Sci.
2011, 235, 161−183.
(47) Hartwig, J. F.; Kawatsura, M.; Hauck, S. I.; Shaughnessy, K. H.;
Alcazar Roman, L. M. J. Org. Chem. 1999, 64, 5575−5580.
(48) Jiang, L.; Stephan, B. L. Palladium-Catalyzed Aromatic Carbon-
Nitrogen Bond Formation. Metal-Catalyzed Cross-Coupling Reactions,
2nd ed.; de Meijere, A., Diederich, F., Eds.; Wiley-VCH: New York,
2004; Chapter 13.
(49) Klenkler, R. A.; Xu, G.; Graham, J. F.; Popvic, Z. D. Appl. Phys.
Lett. 2006, 88, 102101−1:3.
(50) Morariu, S.; Brunchi, C. E.; Cazacu, M.; Bercea, M. J. Chem. Eng.
Data 2011, 56, 1468−1475.
(51) Summers, W. R.; Tewari, Y. B.; Schreiber, H. P. Macromolecules
1972, 5, 12−16.
728
dx.doi.org/10.1021/ma202041u | Macromolecules 2012, 45, 723−728