Communication
J=9.3 Hz), 3.79 ppm (s, 12H); 13C NMR (75 MHz, [D6]acetone): d=
122.7, 123.3, 123.6, 124.1, 124.8, 126.9, 127.5, 129.6, 130.2, 132.3,
147.4, 147.9 ppm; MS: m/z 634.28 [M+]; elemental analysis calcd
for C42H38N2O4: C 79.47, H 6.03; found: C 79.08, H 5.91.
Bis(4-bis(4-methoxyphenyl)amino)phenyl)methanone (3):[16] In
a three-neck flask compound 2 (2 g, 8.72 mmol) and sodium tert-
butoxide (1.2 g, 12.49 mmol) are dissolved in 25 mL anhydrous di-
methylformamide. Then bis(4-fluorophenyl)methanone (0.86 g,
3.94 mmol) in 15 mL anhydrous dimethylformamide solution was
slowly added dropwise over 1 h under N2 atmosphere. The reac-
tion mixture was refluxed for 10 h. Upon cooling, the mixture was
poured into 100 mL ice water, then a deep yellow solid precipitate
was washed with ethanol and filtered to yield a solid (67%).
1H NMR (300 MHz, (CD3)2CO): d=7.58 (d, J=9.0 Hz, 4H), 7.16 (d,
J=6.9 Hz, 8H), 6.95(d, J=6.9 Hz, 8H), 6.76 (d, J=9.0 Hz, 4H),
3.80 ppm (S, 12H); 13C NMR (75 MHz, (CD3)2CO): d=193.0, 158.2,
153.0, 140.1, 132.1, 129.6, 128.0, 116.9, 115.8, 55.7 ppm; MS: m/z
636.26 ppm [M+]; elemental analysis calcd for C41H36N2O5: C 77.34,
H 5.70; found: C 77.02, H 5.59.
Figure 4. Time-course changes in the performance parameters of the solar
&
*
cells with EtheneDTPA ( ) and EtheneTTPA ( ) as the HTMs, respectively.
4,4’,4’’,4’’’-(Ethene-1,1,2,2-tetrayl)tetrakis(N,N-bis(4-methoxyphe-
nyl)aniline) [EtheneTTPA]:[17]
A
suspension of zinc (0.3 g,
lar, the photovoltaic performance is quite different depending
on the number of peripheral substituents. The EtheneTTPA-
based cell affords an overall conversion efficiency of 13.09%,
showing a comparable photovoltaic performance to the spiro-
OMeTAD-based cell (13.87%). We believe that the develop-
ment of highly efficient hole transporting materials compara-
ble to the spiro-OMeTAD is possible through meticulous mo-
lecular design, and studies directed to this goal are now in
progress.
1.28 mmol) in dry tetrahydrofuran (8 mL) was stirred under nitro-
gen at 08C for 10 min. Titanium(IV) chloride (0.07 mL, 0.64 mmol)
was injected slowly over a period of 30 min, the ice-salt-water bath
was removed and the reaction mixture was heated under reflux for
about 2 h. After, a solution of compound 3 (0.2 g, 0.31 mmol) in
dry tetrahydrofuran (2 mL) was added slowly using a needle/sy-
ringe and the reaction was refluxed, overnight. The reaction mix-
ture was quenched with a 5% aqueous solution of ammonium
chloride. The organic extracts were combined, washed with water,
dried over MgSO4, filtered and the solvent was removed using
a rotary evaporator. The crude product was washed with ethanol
and filtered to yield a solid (75%). 1H NMR (300 MHz, (CD3)2CO):
d=6.98 (d, J=8.4 Hz, 8H), 6.86 (d, J=8.4 Hz, 8H), 6.82 (d, J=
9.0 Hz, 4H), 6.66 (d, J=8.4 Hz, 4H), 3.75 ppm (S, 12H); 13C NMR
(75 MHz, (CD3)2CO): d=156.7, 147.5, 141.5, 137.4, 132.9, 127.1,
126.6, 120.4, 115.4, 55.7 ppm; MS: m/z 1240.54 [M+]; elemental
analysis calcd for C82H72N4O8: C 79.33, H 5.85; found: C 79.01, H
5.67.
Experimental Section
Synthesis and characterization of materials
All reactions were carried out under a nitrogen atmosphere. Sol-
vents were distilled as appropriate. All reagents were purchased
from Sigma–Aldrich and TCI. 4-(Bis(4-methoxyphenyl)amino)benzal-
dehyde (1)[23] and 4,4’-dimethoxydiphenylamine (2)[24] were synthe-
sized using procedures from the literature.
Measurements and instruments
(E)-4,4’-(Ethene-1,2-diyl)bis(N,N-bis(4-methoxyphenyl)aniline)
[EthyleneDTPA]:
A
500 mL three-neck round-bottom flask
1H and 13C NMR spectra were recorded on a Varian Mercury 300
spectrometer. Chemical shifts, d, were calibrated against TMS as an
internal standard. Elemental analyses were performed with a Carlo
Elba Instruments CHNS-O EA 1108 analyzer. The absorption and
photoluminescence spectrometer were recorded on a PerkinElmer
Lambda 2S UV–visible spectrometer and Perkin LS fluorescence, re-
spectively. Cyclic voltammetry was carried out with a BAS 100B
(Bioanalytical Systems, Inc.). Redox potential of materials was mea-
sured in dichloromethane solution with 0.1m (nC4H9)4NPF6 as the
supporting salt. The platinum working electrode consisted of a plat-
inum wire sealed in a soft glass tube with a surface of 0.785 mm2,
which was polished down to 0.5 mm with Buehler polishing paste
prior to use in order to obtain reproducible surfaces. The counter
electrode consisted of a platinum wire and the reference electrode
was an Ag/AgCl secondary electrode. Solar cell efficiencies were
characterized under simulated 100 mWcmÀ2 AM 1.5 G irradiation
from a Xe arc lamp with an AM 1.5 global filter. Simulator irradi-
ance was characterized using a calibrated spectrometer and illumi-
nation intensity was set using an NREL certified silicon diode with
an integrated KG1 optical filter; spectral mismatch factors were cal-
culated for each device in this report to be less than 5%. Short cir-
equipped with a reflux condenser, magnetic stir bar, nitrogen inlet
and rubber septum was charged with anhydrous tetrahydrofuran
(150 mL). The flask was cooled to 08C and titanium tetrachloride
(7.36 mL, 38.8 mmol) was added dropwise by syringe. Zinc (5.07 g,
77.6 mmol) was then added in small portions to the emulsion, and
the resulting mixture was refluxed for 45 min. The reaction mixture
was cooled to 08C and a solution of 4-formyltriphenylamine (5.3 g,
19.4 mmol) in anhydrous THF and pyridine (5 mL) was added drop-
wise from an addition funnel. The mixture was then refluxed, and
the progress of the reaction was monitored by TLC (dichlorome-
thane) until completion. The mixture was then cooled and poured
into water (80 mL). The resulting emulsion was stirred for 20 min
and then partitioned in a separatory funnel. The aqueous layer was
extracted with dichloromethane (100 mL), and the combined or-
ganic layers were washed with water (380 mL). The solution was
then dried with MgSO4 and the solvent was removed by rotary
evaporator. The resulting solid was recrystallized from ethanol to
1
yield a yellow solid (4.45 g, 90%). H NMR (300 MHz, [D6]acetone):
d=7.51 (d, 2H, J=8.4 Hz), 7.42 (d, 2H, J=8.4 Hz), 7.07 (d, 10H, J=
8.7 Hz), 7.00 (d, 2H, J=9.0 Hz), 6.92 (d, 6H, J=9.0 Hz), 6.84 (d, 4H,
Chem. Eur. J. 2015, 21, 15919 – 15923
15922
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