Organometallics
ARTICLE
Chemicals. Bis(2-bromophenyl)acetylene33 and [2-(dimesitylboryl)-
phenyl][2-(diphenylphosphanyl)phenyl]acetylene (1c)11 were prepared
according to the literature methods. All reactions were performed under an
argon atmosphere, unless stated otherwise.
dimethylbenzene (2.24 g, 4.98 mmol) and 4 (0.876 g, 1.99 mmol) as
starting materials. Purification by filtration with a pad of silica gel
(PSQ100B, AcOEt, Rf = 0.93), followed by washing with hexane,
afforded 0.998 g (0.980 mmol) of 2e in 49% yield as yellow solids.
Mp > 275 °C (decomposition without melting was observed at 275 °C
under N2 atmosphere). Td5: 275 °C. 1H NMR (400 MHz, CD2Cl2): δ
1.99 (s, 12H), 6.94 (s, overlapped, 4H), 6.94ꢀ7.00 (m, 2H), 7.10 (d, J =
6.4 Hz, 1H), 7.29 (dt, J = 7.4 Hz, 6.4 Hz, 1H), 7.50ꢀ7.69 (m, 7H),
7.73ꢀ7.82 (m, 7H). 13C{1H, 19F} NMR (150 MHz, CD2Cl2): δ 25.77
(s, CH3), 109.31 (s, C), 110.77 (s, C), 116.67 (s, C), 117.82 (s, C),
118.63 (d, C, JCP = 82.3 Hz), 120.39 (s, CH), 123.04 (t, C, JCF = 23.9
Hz), 124.40 (s, CH), 125.55 (s, CH), 125.80 (s, CH), 127.86 (d, CH,
JCP = 8.2 Hz), 127.90 (d, C, JCP = 99.6 Hz), 127.96 (d, CH, JCP = 5.8 Hz),
129.19 (d, C, JCP = 144.0 Hz), 129.97 (d, CH, JCP = 10.7 Hz), 130.49 (d,
CH, JCP = 13.1 Hz), 131.82 (s, CH), 133.35 (d, CH, JCP = 11.5 Hz),
135.12 (d, CH, JCP = 2.5 Hz), 135.66 (d, CH, JCP = 1.7 Hz), 141.78
(s, C), 142.04 (d, C, JCP = 18.2 Hz), 150.72 (d, C, JCP = 25.5 Hz).
11B{1H} NMR (128 MHz, CD2Cl2): δ ꢀ5.03. 19F{1H} NMR (376
MHz, CDCl3): δ ꢀ125.40, ꢀ122.78, ꢀ110.17, ꢀ80.77. 31P{1H} NMR
(162 MHz, CD2Cl2): δ 13.94. HRMS (APCI): calcd for C50H35BF18P
([M + H]+) 1019.2282, found 1019.2321.
(2-Bromophenyl)[2-(diphenylphosphanyl)phenyl]acetyl-
ene (4). To a solution of bis(2-bromophenyl)acetylene (10.0 g,
27.3 mmol) in anhydrous THF (97 mL) was added n-BuLi in hexane
(1.64 M, 16.6 mL, 27.3 mmol) dropwise over 1.5 h at ꢀ78 °C. After
stirring for 1 h, Ph2PCl (5.0 mL, 6.1 g, 28 mmol) was added over 10 min,
and the resulting mixture was stirred for 2 h at the same temperature.
The resulting mixture was then concentrated under reduced pressure.
Toluene (deoxygenated by Ar bubbling for 30 min) was added, and the
resulting suspension was filtered through a plug of Celite under an argon
atmosphere and rinsed with toluene. After concentration of the filtrate,
the resulting mixture was subjected to silica gel column chromatography
(PSQ100B, toluene, Rf = 0.93), followed by further purification by
washing with cyclohexane to afford 9.77 g (22.1 mmol) of 4 in 81% yield
as colorless solids: mp 108.4ꢀ109.2 °C. 1H NMR (400 MHz, CD2Cl2):
δ 6.84 (dd, J = 3.2 Hz, 7.6 Hz, 1H), 7.12ꢀ7.34 (m, overlapped, 15H),
7.53 (d, J = 8.0 Hz, 1H), 7.63 (dd, J = 3.2 Hz, 7.0 Hz, 1H). 13C{1H}
NMR (100 MHz, CD2Cl2): δ 92.98 (d, C, 3JCP = 7.5 Hz), 94.10 (d, C,
4JCP = 2.4 Hz), 125.08 (d, C, 2JCP = 17.3 Hz), 127.06 (s, CH), 127.32
(s, C), 127.61(s, C), 128.50 (s, CH), 128.61 (s, CH), 128.82 (s, CH),
128.82 (d, CH, 2JCP = 12.4 Hz), 129.67 (s, CH), 132.37 (s, CH), 132.68
(s, CH), 132.83 (d, CH, 3JCP = 3.3 Hz), 133.53 (s, CH), 134.14 (d, CH,
2JCP = 19.7 Hz), 136.58 (d, C, 1JCP = 10.7 Hz), 140.82 (d, C, 1JCP = 14.0
Hz). 31P{1H} NMR (162 MHz, CD2Cl2): δ ꢀ8.93. HRMS (APCI):
calcd for C26H19BrP ([M + H]+) 441.0408, found 441.0408.
Compound 2c. A Schlenk flask was charged with 1c (0.101 g, 0.166
mmol) and CH2Cl2 (deoxygenated by Ar bubbling for 30 min, 136 mL)
and was immersed in a solution filter (KNO3 0.4 M aqueous solution)
with a thickness of ca. 5 cm. This mixture was irradiated with a high-
pressure mercury lamp for 1 h. After concentration under reduced
pressure, the resulting mixture was subjected to reversed-phase silica gel
column chromatography (Wakosil 40C18, CH3CN, Rf = 0.53) to afford
62.0 mg (0.102 mmol) of 2c as yellow solids. Mp > 147 °C
(decomposition without melting was observed at 147 °C under N2
Compound 2d. To a mixture of Mg (turnings, 0.166 g, 6.83 mmol)
and anhydrous Et2O (5.0 mL) was added 5-chloro-2-iodo-1,3-dimethyl-
benzene (1.33 g, 4.99 mmol). The resulting mixture was stirred at reflux
temperature for 2 h. The prepared Grignard reagent in Et2O was added
1
atmosphere). Td5: 147 °C. H NMR (400 MHz, CDCl3): δ 1.92 (s,
12H), 2.10 (s, 6H), 6.54 (s, 4H), 6.89ꢀ6.90 (m, 2H), 7.02ꢀ7.04 (m,
1H), 7.24 (dt, J = 4.8 Hz, 7.4 Hz, 1H), 7.48ꢀ7.71 (m, 7H),
7.72ꢀ7.79(m, 6H), 7.89 (dd, J = 3.4 Hz, 7.8 Hz, 1H). 13C{1H} NMR
(100 MHz, CD2Cl2): δ 20.46 (s, CH3), 25.69 (s, CH3), 119.21 (d, C,
1JCP = 82.3 Hz), 119.954 (s, CH), 123.48 (s, CH), 125.18 (s, CH),
126.54 (d, C, 1JCP = 127.2 Hz), 126.95 (d, C, 1JCP = 103.2 Hz), 127.47(d,
CH, JCP = 10.7 Hz), 127.82 (s, C), 128.26 (d, CH, JCP = 9.1 Hz), 128.93
(s, C), 129.60 (d, CH, JCP = 10.7 Hz), 130.32 (d, CH, JCP = 13.2 Hz),
131.70 (s, CH), 133.37 (d, CH, JCP = 11.5 Hz), 134.82 (d, CH, JCP = 3.3
dropwise into BF3 OEt2 over 1 min at 0 °C. After stirring for 1 h, all
3
volatiles were removed under reduced pressure, and anhydrous hexane
(10 mL) was added. The resulting suspension was filtered under an
argon atmosphere and rinsed with anhydrous hexane. After concentra-
tion of the filtrate, the resulting solids were dissolved in anhydrous THF
(2.0 mL) to prepare a Ar2BF solution.
Another brown-colored Schlenk flask was charged with 4 (0.696 g,
1.57 mmol) and anhydrous THF (10 mL). A pentane solution of t-BuLi
(1.55 M, 2.0 mL, 3.2 mmol) was added to this mixture over 5 min at
ꢀ78 °C. After stirring for 1 h, the aforementioned Ar2BF solution in
THF was added over 10 min, and the resulting mixture was stirred at
ꢀ78 °C for 3 h and then at 60 °C for 5 h. After removal of volatiles, the
mixture was subjected to silica gel column chromatography (PSQ100B,
CH2Cl2, Rf = 0.93), followed by further purification by washing with
hexane to afford 0.457 g (0.702 mmol) of 2d in 44% yield as yellow
solids. Mp > 267 °C (decomposition without melting was observed at
Hz), 135.42 (d, CH, 4JCP = 1.6 Hz), 141.04 (s, C), 141.81 (d, C, JCP
=
18.2 Hz), 151.48 (d, C, JCP =25.6 Hz). 11B{1H} NMR (128 MHz, THF-
d8): δ ꢀ3.29. 31P{1H} NMR (162 MHz, THF-d8): δ 14.70. HRMS
(APCI): calcd for C44H41BP ([M + H]+) 611.3039, found 611.3051.
X-ray Crystallographic Analysis of 1c. Single crystals of 1c
suitable for X-ray crystallographic analysis were obtained by recrystalli-
zation from cyclohexane. Intensity data were collected at 100 K with Mo
KR radiation (λ = 0.71070 Å) and a graphite monochromator. A total of
24 686 reflections were measured at a maximum 2θ angle of 50.0°, of
which 6602 were independent reflections (Rint = 0.0610). The structure
was solved by the direct method (SIR97)34 and refined by full-matrix
least-squares on F2 (SHELXL-97).35 All non-hydrogen atoms were
refined anisotropically, and all hydrogen atoms were placed using AFIX
instructions. The crystal data are as follows: formula C44H40BP,
fw = 610.54, crystal size 0.20 mm ꢁ 0.20 mm ꢁ 0.15 mm, monoclinic,
P21/c (#14), a = 17.177(3) Å, b = 12.4963(19) Å, c = 17.480(3) Å,
1
267 °C under N2 atmosphere). Td5: 267 °C. H NMR (400 MHz,
CD2Cl2): δ 1.95 (s, 12H), 6.72 (s, 4H), 6.93ꢀ6.97 (m, 2H), 7.05ꢀ7.07
(m, 1H), 7.28 (dt, J = 4.80 Hz, 7.20 Hz, 1H), 7.52ꢀ7.67 (m, 7H),
7.74ꢀ7.83 (m, 7H). 13C{1H} NMR (100 MHz, CD2Cl2): δ 25.60 (s,
CH3), 118.80 (d, C, 1JCP = 82.4 Hz), 124.03 (s, CH), 125.57 (s, CH),
127.39 (s, CH), 127.75(d, CH, JCP = 11.6 Hz), 127.96 (d, CH, JCP = 9.1
Hz), 128.04 (d, C, 1JCP = 100.4 Hz), 128.15 (s, C), 129.83 (d, CH, JCP
=
11.5 Hz), 130.42 (d, CH, JCP = 12.3 Hz), 131.68 (s, CH), 133.31 (d, CH,
JCP = 11.5 Hz), 135.00 (d, CH, JCP = 3.3 Hz), 135.60 (d, CH, 4JCP = 1.6
Hz), 141.78 (d, C, JCP = 18.1 Hz), 143.18 (s, C), 150.89 (d, C, JCP = 26.4
Hz), signals of three carbons bound to the boron atom were not
observed. 11B{1H} NMR (128 MHz, CD2Cl2): δ ꢀ5.78. 31P{1H}
NMR (162 MHz, CD2Cl2): δ 13.36. HRMS (APCI): calcd for
C42H34BCl2P ([M + H]+) 651.1946, found 651.1921.
β = 114.0966(19)°, V = 3425.1(10) Å3, Z = 4, Dcalcd = 1.184 g cmꢀ3
,
μ = 0.111 mmꢀ1, R1 = 0.0490 (I > 2σ(I)), wR2 = 0.1207 (all data),
GOF = 1.089.
Photophysical Data Measurements. UVꢀvisible absorption
spectra were recorded on a Shimadzu UV-3510 spectrometer with a
resolution of 0.5 nm. Emission spectra of solution samples were
measured with a Hitachi F-4500 spectrometer with a resolution of
1 nm. Dilute solutions in degassed spectral grade solvents in a 1 cm
Compound 2e. This compound was prepared in a similar
manner to that described for 2d, using 5-nonafluorobutyl-2-iodo-1,3-
3877
dx.doi.org/10.1021/om200453w |Organometallics 2011, 30, 3870–3879