Full Paper
Crystal data for C17H15O2BF2 (1dBF2): Yellow blocks, 0.80.6
0.2 mm3, monoclinic, C2/c, a=15.3182(13), b=7.0036(5), c=
the FL emission, the lFL,C of type III crystals are 467–469 nm,
which are smaller values than those for the type II crystals.
Moreover, the participation of S0–Sn transitions may lead to the
FL with long tFL of 5.6–6.8 ns. The insight gained in this effort
concerning the novel “excited multimer” FL domain could
shed light on ways to manipulate FL properties through
changes in the nature of molecular aggregation.
13.5957(10) , b=95.440(2)8, V=1452.01(19) 3, Z=4, 1calcd
=
1.386 gcmÀ3, m=0.105 mmÀ1, MoKa radiation, l=0.71070 , T=
93.1 K, 2qmax =55.08, 6790 reflections measured, 1645 unique re-
flections, Rint =0.026, 102 parameters, R1 =0.047 (I>2sI), wR2 =
0.149 (all data), CCDC-1412043.
Crystal data for C21H23O2BF2 (1eBF2): Yellow needles, 1.00.5
0.1 mm3, monoclinic, C2/c, a=21.794(3), b=7.0013(13), c=
16.034(3) , b=129.094(6)8, V=1898.9(5) 3, Z=4, 1calcd
=
1.246 gcmÀ3, m=0.091 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 8709 reflections measured, 2150 unique reflec-
tions, Rint =0.092, 121 parameters, R1 =0.070 (I>2sI), wR2 =0.234
(all data), CCDC-412046.
Experimental Section
General
Melting points were measured by using a Rigaku Thermo plus EVO
II/DSC8230 differential scanning calorimeter. The X-ray diffraction
data for the crystals were collected by using a Rigaku RAXIS-RAPID
diffractometer and were refined by using SHELX[48] and Yadokari-
XG 2009[49] programs. UV/Vis absorption spectra were recorded by
using a JASCO V-570 spectrophotometer. FL spectra were recorded
by using a JASCO FP-8500 spectrophotometer. The tFL values were
determined by using a HORIBA Jobin Yvon FluoroCube lifetime
spectrofluorometer and analyzed by DAS6 FL decay analysis soft-
ware. The absolute FFL values were determined by utilizing the in-
tegrating sphere method with a Hamamatsu Photonics C9920–02
absolute photoluminescence quantum yields measurement
system.
Crystal data for C23H27O2BF2 (1 fBF2): Pale yellow platelets, 1.0
0.50.4 mm3, monoclinic, C2/c, a=29.455(3), b=7.0775(6), c=
10.4286(8) , b=104.082(3)8, V=2108.7(3) 3, Z=4, 1calcd
=
1.210 gcmÀ3, m=0.086 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 9679 reflections measured, 2387 unique reflec-
tions, Rint =0.074, 131 parameters, R1 =0.061 (I>2sI), wR2 =0.194
(all data), CCDC-1412042.
Crystal data for C21H27O2BF2Si2 (1gBF2): Pale yellow platelets, 0.6
0.30.1 mm3, monoclinic, C2/c, a=29.625(5), b=7.2557(15), c=
10.8706(18) , b=103.918(4)8, V=2268.0(7) 3, Z=4, 1calcd
=
1.220 gcmÀ3, m=0.186 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 10636 reflections measured, 2546 unique re-
flections, Rint =0.194, 131 parameters, R1 =0.085 (I>2sI), wR2 =
0.248 (all data), CCDC-1412044.
Preparation of organic substances
Diaroylmethanes 1a–gH, possessing two alkyl or trimethylsilyl
groups, were prepared by using Claisen condensation reactions be-
tween the corresponding 4-substituted methyl benzoate and 4’-
substituted acetophenone. Treatment of 1a–gH with BF3·OEt2 gave
the corresponding BF2 complexes 1a–gBF2.[43,45]
Measurement of UV/Vis absorption and FL spectra
UV/Vis absorption spectra were recorded for approximately 0.5
10À5 m CH2Cl2 solutions of 1a–gBF2. FL spectra were recorded by
using the same solutions and crystals of these substances with
a lEX of 365 nm. Analyses of time-dependent changes of FL intensi-
ties in CH2Cl2 solutions and in crystals were carried out by using
first- and multi-order fittings to give tFL,S and tFL,C, respectively.
X-ray crystallographic analysis
X-ray crystallographic analyses were performed on single crystals
of 1a–gBF2, which were obtained by recrystallization from benzene
crystallographic data for this paper. These data are provided free
Computational methods
Theoretical studies were carried out by using the Gaussian 09 pro-
gram.[47] Geometry optimizations for 1a–gBF2 were carried out by
DFT calculations with the B3LYP method and a 6–311+G(d) basis
set. Single-point calculations for a single molecule or two or three
stacked molecules in geometries derived from the X-ray-deter-
mined packing structures were performed with a 6–311G(d) basis
set to determine EH and EL. Electronic transitions associated with
a single molecule or two or three stacked molecules were estimat-
ed by using TD-DFT calculations with a 6–311G(d) basis set.
Crystal data for C23H27O2BF2 (1aBF2): Pale yellow needles, 1.0
0.50.2 mm3, monoclinic, C2/c, a=17.257(4), b=6.9753(14), c=
17.605(4) , b=93.218(5)8, V=2115.8(8) 3, Z=4, 1calcd
=
1.206 gcmÀ3, m=0.086 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 9801 reflections measured, 2408 unique reflec-
tions, Rint =0.103, 129 parameters, R1 =0.081 (I>2sI), wR2 =0.234
(all data), CCDC-1412048.
Crystal data for C21H23O2BF2 (1bBF2): Pale yellow needles, 0.8
0.30.2 mm3, monoclinic, C2/c, a=16.8514(15), b=6.8712(5), c=
15.9835(17) , b=93.412(4)8, V=2115.8(8) 3, Z=4, 1calcd
=
Acknowledgments
1.281 gcmÀ3, m=0.093 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 8690 reflections measured, 2103 unique reflec-
tions, Rint =0.068, 120 parameters, R1 =0.054 (I>2sI), wR2 =0.186
(all data), CCDC-1412045.
A.S. and M.T. are grateful for financial support in the form of
a Grant-in-Aid for JSPS Fellows from the Japan Society for the
Promotion of Science (Nos. 25·10489 and 26·11802, respective-
ly). E.O. acknowledges financial support from the Ministry of
Education, Culture, Sports, Science and Technology (MEXT),
Japan, in the form of a Grant-in-Aid for Young Scientists (B)
(No. 24750044) and the Challenging Exploratory Research (No.
26620034). K.M. is grateful for financial support from MEXT,
Japan in the form of a Grant-in-Aid for Scientific Research (C)
Crystal data for C19H19O2BF2 (1cBF2): Pale yellow platelets, 0.8
0.50.3 mm3,
orthorhombic,
Pnma,
a=12.5719(12),
b=
17.2908(19), c=7.9430(7) , V=1726.6(3) 3, Z=4, 1calcd
=
1.262 gcmÀ3, m=0.094 mmÀ1, MoKa radiation, l=0.71070 , T=
298 K, 2qmax =55.08, 15820 reflections measured, 2014 unique re-
flections, Rint =0.083, 118 parameters, R1 =0.086 (I>2sI), wR2 =
0.297 (all data), CCDC-1412047.
Chem. Eur. J. 2015, 21, 18128 – 18137
18136
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