W. Sun et al.
1.34 (s, 12H), 1.7–2.0 (m, 4H), 6.9–7.1 (m, 8H), 7.21 (m, 4H), 7.58 (m,
2H), 7.76 ppm (m, 2H).
ence absorption measurement. The dipolar terpyridine li-
gands 1L, 2L, and 3L exhibit two-photon absorption at the
near-IR region, with the 2PA band maxima coincide with
their respective 1PA band maxima. The general trend of the
Ligand 1L: Compound 9 (0.75 g, 0.80 mmol) and 4’-bromo-2,2’:6’,2’’-ter-
pyridine (311 mg, 1.00 mmol) were added to toluene (50 mL). 2mK2CO3
aqueous solution (2.5 mL) was added. The mixture was degassed in
2PA cross-section (s2) value follows the sequence of s2
ACHTUNGTNER(NUNG 2L)
argon for 20 min. [PdACHTNUTRGNE(UNG PPh3)4] (46 mg, 0.04 mmol) was added. The mix-
> s2(3L) > s2(1L), suggesting that triple bond connection
G
ACHTUNGTRENNUNG
ture was heated to reflux under argon overnight. The organic layer was
washed with water, dried over MgSO4 and filtered. After the solvent was
removed, the crude product was purified on a silica gel column eluted by
CH2Cl2 to give a pale yellow solid (422 mg, 67%). 1H NMR (500 MHz,
CDCl3): d = 0.6 (m, 8H), 0.7–1.0 (m, 22H), 1.86–2.10 (m, 4H), 7.03 (m,
2H), 7.11 (m, 6H), 7.16 (m, 4H), 7.38 (t, J=6.5 Hz, 2H), 7.66 (m, 1H),
7.76 (m, 1H), 7.86 (t, J=7.0 Hz, 2H), 7.91 (2H, t, J=7.0 Hz), 8.70 (d, J=
8.0 Hz, 2H), 8.78 ppm (m, 4H); HRMS: m/z (%): calcd for [C56H61N4]+:
789.4891; found: 789.4875 (100).
between the donor and acceptor favors the 2PA. The maxi-
mum 2PA cross-section was obtained to be 448 GM in 2L.
The s2 values of the platinum complexes (600–2000 GM)
measured by Z-scan experiment are much larger than those
of their corresponding ligands, with the largest s2 value to
be 2000 GM at 800 nm for 2. To the best of our knowledge,
these values are the largest s2 values reported for platinum
complexes to date. Complex 2 with the ethynylene linker
shows much stronger 2PA than complex 3 with the vinylene
linker. However, we should point out that the s2 values ob-
tained by the Z-scan method could be overestimated com-
pared to those obtained by the two-photon excited fluores-
cence method.
Complex 1: Ligand 1L (560 mg, 0.71 mmol) and [PtACTHNUGRTNEUNG(dmso)2Cl2] (300 mg,
0.73 mmol) were added to CHCl3 (80 mL). The mixture was heated to
reflux under argon for 24 h. After the solvent was removed, the residue
was purified on an Al2O3 column eluted by CH2Cl2, followed by CH2Cl2/
MeOH 1:1. The crude product was purified by recrystallization from
CH2Cl2/hexane/Et2O to give
a
red solid (486 mg, 65%). 1H NMR
(500 MHz, CDCl3): d = 0.6 (m, 8H), 0.7–1.2 (m, 22H), 2.0 (m, 2H), 2.35
(m, 2H), 7.13 (m, 8H), 7.29 (m, 4H), 7.48 (m, 2H), 7.70 (d, J=8.0 Hz,
1H), 7.97 (d, J=8.0 Hz, 1H), 8.32 (m, 3H), 8.53 (m, 3H), 8.77 (t, J=
8.0 Hz, 2H), 9.11 ppm (d, J=7.5 Hz, 2H); HRMS: m/z (%): calcd for
[C56H60N4PtCl]+: 1019.4156; found: 1019.4159 (100); elemental analysis
calcd (%) for C56H60N4PtCl2·2.5CH2Cl2: C 55.30, H 5.12, N 4.41; found:
C 55.75, H 5.30, N 4.57.
Experimental Section
Compound 10: Compound 8 (1.10 g, 1.70 mmol) and 2-methyl-3-butyn-2-
ol (0.33 mL, 3.40 mmol) was added to triethylamine (30 mL). CuI
(7.00 mg, 0.04 mmol), PPh3 (18.00 mg, 0.07 mmol), and [PdACHTUNGTRENNUNG(PPh3)4]
Synthesis: All reagents and solvents (analytical grade) were purchased
from VWR Scientific Company and used without further purification
unless otherwise stated. The silica gel (230–400 mesh) was purchased
from Alfa Aesar Company. Neutral Al2O3 (standard grade, 150 mesh)
was purchased from Aldrich Company. All products were characterized
by 1H NMR, elemental analysis, and HRMS. 1H NMR spectra were ob-
(50.0 mg, 0.04 mmol) were added. The mixture was heated to reflux
under argon overnight. The solvent was removed, and the residue was
dissolved in CH2Cl2. The solution was washed with water, and dried over
Na2SO4. After the solvent was removed, the crude product was purified
on a silica gel column eluted by hexane/CH2Cl2 1:1 to give a colorless oil
(435 mg, 40%). 1H NMR (400 MHz, CDCl3): d = 0.46–0.53 (m, 8H),
0.68–0.86 (m, 22H), 1.62 (t, J=2.8 Hz, 6H), 1.75–1.89 (m, 4H), 1.99 (t,
J=3.2 Hz, 1H), 7.01 (m, 8H), 7.22 (m, 4H), 7.34 (m, 2H), 7.52 ppm (m,
2H).
tained using
a Varian 400 MHz or 500 MHz VNMR spectrometer.
HRMS was conducted on a Bruker Daltonics BioTOF system with elec-
trospray ionization (ESI) source. Elemental analyses were conducted by
NuMega Resonance Labs, Inc. in San Diego, CA.
The precursors 2-iodofluorene (5),[26] 2-bromo-7-iodofluorene (6),[18] 2-
bromo-9,9-di(2-ethylhexyl)-7-iodofluorene (7), 2-bromo-9,9-di(2-ethyl-
hexyl)-7-diphenylaminofluorene (8),[18] 4’-bromo-2,2’:6’,2’’-terpyridine,[27]
Compound 11: Compound 10 (0.41 g, 0.64 mmol) and KOH (0.30 g,
5.36 mmol) were added to 2-propanol (10 mL). The mixture was heated
to reflux under argon for 3 h. After the solvent was removed, the residue
was purified on a silica gel column eluted by hexane to give a colorless
4’-vinyl-2,2’:6’,2’’-terpyridine
(12),[28]
4’-(trifluoromethyl)sulfonyloxy-
2,2’:6’,2’’-terpyridine (OTf-tpy),[28] were synthesized according to the pro-
1
oil (268 mg, 72%). H NMR (400 MHz, CDCl3): d = 0.51 (m, 8H), 0.68–
cedures reported in the literature.
0.90 (m, 22H), 1.55–1.99 (m, 4H), 3.06 (s, 1H), 6.96–7.06 (m, 8H), 7.23
(m, 4H), 7.42 (m, 2H), 7.53 ppm (m, 2H); HRMS: m/z (%): calcd for
[C43H51N]+: 581.4016; found: 581.4019 (100).
2-Bromo-9,9-di(2-ethylhexyl)-7-diphenylaminofluorene (8): 2-Bromo-9,9-
di(2-ethylhexyl)-7-iodofluorene (7) (7.00 g, 0.012 mol), diphenylamine
(2.58 g, 0.015 mol), [18]crown-6 (0.26 g, 0.001 mol), Cu (1.50 g,
0.023 mol), and K2CO3 (2.60 g, 0.019 mol) were added to mesitylene
(40 mL). The mixture was heated to reflux under argon overnight. After
the solvent was removed, the residue was dissolved in Et2O. The organic
phase was washed with water, and dried over MgSO4. After removal of
the solvent, the crude product was purified by a silica gel column using
Ligand 2L: Compound 11 (323 mg, 0.56 mmol) and OTf-tpy (212 mg,
0.56 mmol) were added to a mixture of benzene (50 mL) and isopropyla-
mine (20 mL). [PdACTHNUTRGNEUNG(PPh3)4] (30 mg, 0.02 mmol) was then added. The mix-
ture was heated to reflux under argon overnight. After the solvent was
removed, the residue was dissolved in CH2Cl2. The solution was washed
with water, and dried over Na2SO4. After the solvent was removed, the
crude product was purified on a neutral Al2O3 column eluted by hexane/
CH2Cl2 10:1 to remove the unreacted reagent, and then eluted with
hexane/CH2Cl2 1:1 to give a pale yellow solid (341 mg, 75%). 1H NMR
(400 MHz, CDCl3): d = 0.58 (m, 8H), 0.7–1.0 (m, 22H), 1.8–2.0 (m, 4H),
7.0 (m, 8H), 7.23 (t, J=8.1 Hz, 4H), 7.35 (m, 2H), 7.57 (m, 4H), 7.87 (dt,
J=7.5, 1.5 Hz, 2H), 8.63 (m, 4H), 8.74 ppm (dt, J=4.8 Hz, 2H); HRMS:
m/z (%): calcd for [C58H61N4]+: 813.4891; found: 813.4917 (100).
1
hexane to give a colorless oil (4.50 g, 42%). H NMR (400 MHz, CDCl3):
d = 0.56 (m, 8H), 0.75–1.00 (m, 22H), 1.73–1.92 (m, 4H), 7.00–7.12 (m,
8H), 7.25 (m, 4H), 7.46 (m, 3H), 7.55 ppm (m, 1H).
7-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-di(2-ethylhexyl)fluo-
ren-2-yl-diphenylamine (9): Compound 8 (1.0 g, 1.12 mmol) was dissolved
in dried THF (50 mL) at ꢀ788C. 1.6m BuLi/hexane solution (2.0 mL,
3.20 mmol) was added slowly. The mixture was stirred at ꢀ788C for 1 h.
2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
(0.42 mL,
Complex 2: Ligand 2L (340 mg, 0.42 mmol) and [PtACTHNUGRTNEUNG(dmso)2Cl2] (212 mg,
1.12 mmol) was added dropwise. The mixture was allowed to reach room
temperature and stirred at RT overnight. After that brine (50 mL) was
added to terminate the reaction. The aqueous layer was extracted with
Et2O (3ꢁ30 mL). The combined organic layer was dried over Na2SO4.
After removal of the solvent, the crude product was purified by a silica
gel column using hexane/toluene 5:1 to give a colorless oil (735 mg,
0.52 mmol) were added to CHCl3 (80 mL). The mixture was heated to
reflux under argon for 24 h. After the solvent was removed, the residue
was purified by an Al2O3 column eluted first by CH2Cl2/CH3CN 5:2, and
then by CH2Cl2/MeOH 10:1. The crude product was further purified by
recrystallization from CH2Cl2/hexane/Et2O to give a red solid (258 mg,
57%). 1H NMR (400 MHz, CDCl3): d = 0.6 (m, 8H), 0.7–1.0 (m, 22H),
1
70%). H NMR (400 MHz, CDCl3): d = 0.50 (m, 8H), 0.6–0.9 (m, 22H),
2488
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 2479 – 2491