T.-R. Chen et al. / Journal of Organometallic Chemistry 691 (2006) 799–804
803
3. Experimental
7.33 (m, 6H, ph and imidazole), 7.27 (m, 7H, ph and imid-
azole). MS data: 409.29 (26.643%), 332.2 (100%), 295.2
(11.59%), 245.2 (19.26%), 239.2 (19.37%), 166.1 (9.77%),
91.1 (6.69%). Anal. Calc. for C28H20N3B (MW = 409.2):
C, 82.11; H, 4.88; N, 10.26. Found: C, 82.09; H, 4.93; N,
10.24%.
3.1. General procedure
All starting materials were purchased from Aldrich
Chemical Co. 1H and 13C NMR spectra were recorded
on the Bruker 300 MHz NMR spectrometers in CDCl3.
Thermogravimetric analyses (TGA) were performed on a
Perkin–Elmer thermogravimeter (Pyris 1) under a dry
nitrogen gas flow at the heating rate of 20 ꢁC/min. Glass
transition temperature (Tg) and melting point (Tm) of
materials were determined by differential scanning calorim-
eter (DSC) of the Perkin–Elmer differential scanning calo-
rimeter (DSC-7). The absorption spectra were recorded
with the HP-8453A UV–vis photodiode array spectropho-
tometer. The EL spectrum and the Commission Internatio-
nale de IÕEclairage (CIE) co-ordinates were measured by
Pro-650 Spectroscanner, the current–voltage (I–V) charac-
teristics were measured by Keithley 2400 Source meter.
Photoluminescence (PL) was measured by Model LS 55
luminescence Spectrometer.
3.5. BF2(2-(2-pyridyl)naphtho[b]imidazole) (2)
1
Pale yellow solid. 30% yield. M.p. > 250 ꢁC. H NMR
(500 MHz, DMF-d7, 293 K),
d ppm: 8.69 (d, 1H,
J = 6.3 Hz, pyridyl), 8.56 (d, 1H, J = 7.8 Hz, pyridyl),
8.11 (s, 2H, imidazole), 7.95 (m, 3H, pyridyl and imidaz-
ole), 7.43 (m, 3H, imidazole and imidazole). Anal. Calc.
for C16H10N3BF2 (MW = 293.09): C, 65.57; H, 3.44; N,
14.34. Found: C, 65.53; H, 3.50; N, 14.30%.
3.6. Determination of the crystal structure
The diffraction data of PNI and complex 1 were col-
lected on a Bruker AXS P4 diffractometer, which is
equipped with graphite-monochromated Mo Ka radiation
˚
3.2. Synthesis of 2-(2-pyridyl)naphtho[b]imidazole (PNI)
(k = 0.71073 A). Structure refinements were carried out
using the SHELXTL software package [28]. The structure fac-
tors were obtained after Lorentz and polarization correc-
tions. The positions of some of the heavier atoms were
located by the direct method. The remaining atoms were
found in a series of alternating difference Fourier maps
Pyridine-2-carboxylic acid (20.0 mmol, 2.46 g), 2,3-dia-
minonaphthalene (20.0 mmol, 3.16 g), and polyphosphoric
acid (PPA, 20 ml) were added to a flask. The mixture was
heated at 200 ꢁC for 4 h. After cooling to room T, the res-
idue was slowly added to deionized water (500 ml) with
stirring. The solid was collected by suction filtration and
purified by column chromatography. Colorless crystals of
Table 2
Crystal data and structure refinement parameters
Compound
PNI
1
1
PNI were obtained in 80% yield. M.p. >250 ꢁC. H NMR
Empirical formula
Formula weight
Crystal system
Space group
C
245.28
Orthorhombic
P2(1)2(1)2(1)
16H11N3
C28H20B N3
409.2
Triclinic
(500 MHz, DMF-d7, 293 K), d ppm: 13.3 (s, 1H, NH),
8.83 (d, 1H, J = 4 Hz, pyridyl), 8.58 (d, 1H, J = 7.8 Hz,
pyridyl), 8.40 (s, 1H, imidazole), 8.21 (s, 1H, imidazole),
8.13 (dd, 2H, J = 7.7, 1.7 Hz, imidazole), 8.07 (t, 1H,
J = 10, 1.2 Hz, pyridyl), 7.62 (m, 1H, imidazole), 7.45 (m,
2H, pyridyl). Anal. Calc. for C16H11N3 (MW = 245.28):
C, 78.36; H, 4.48; N, 17.14. Found: C, 78.31; H, 4.50; N,
17.11%.
ꢀ
P1
Unit cell dimensions
˚
a (A)
10.866(2)
14.3173(17)
23.011(2)
90
90
90
3579.7(9)
12
1.365
0.084
1536
9.2216(8)
9.6733(16)
15.2655(17)
97.220(10)
90.921(8)
115.787(8)
1212.6(3)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
Volume (A )
3.3. Syntheses of 1 and 2
Z
Calculated density (Mg mꢁ3
Absorption coefficient (mmꢁ1
F(000)
)
1.237
0.179
470
)
Complexes 1 and 2 were prepared in dry THF by react-
ing, in a 1:1.05 molar ratio, PNI with triphenylboron or
boron trifluoride. The solutions were refluxed for 12 h
under nitrogen. Selected analytical data concerning 1 and
2 are:
Crystal size (mm)
h Range for data collection (ꢁ)
Reflections collected
0.2 · 0.5 · 0.3
1.77–24.99
4394
0.2 · 0.6 · 0.4
2.36–25.00
5039
Data/restraints/parameters
Goodness-of-fit on Fꢁ2
4177/0/515
1.054
4200/0/317
1.134
Final R indices [I > 2sigma(I)]
R1 = 0.0647
wR2 = 0.1471
R1 = 0.1263
wR2 = 0.1838
0.320 and ꢁ0.353
R1 = 0.0783
wR2 = 0.2017
R1 = 0.1125
wR2 = 0.2266
0.725 and ꢁ0.362
3.4. BPh2(2-(2-pyridyl)naphtho[b]imidazole) (1)
R indices (all data)
1
Pale yellow solid. 35% yield. M.p. > 250 ꢁC. H NMR
(500 MHz, DMF-d7, 293 K),
d ppm: 8.67 (d, 1H,
Largest difference peak
ꢁ3
˚
and hole (e A
)
J = 13 Hz, pyridyl), 8.63 (d, 1H, J = 13.5 Hz, pyridyl),
8.40 (s, 1H, imidazole), 8.29 (t, 1H, J = 15, 2 Hz, pyridyl),
8.0 (dd, 1H, J = 13, 1.2 Hz, pyridyl), 7.84 (s, 1H, imidaz-
ole), 7.81 (d, 1H, 7.5 Hz, pyridyl), 7.65 (m, 1H, imidazole),
P
P
P
P
R1 = iFo| ꢁ |Fci/ Fo|; wR2 ¼ ½ wðF 2o ꢁ F c2Þ = wðF 2oÞ2ꢃ1=2; quality-
2
P
2
1=2
of-fit ¼ ½ wðjF 2oj ꢁ jF 2c jÞ =Nobserved ꢁ Nparameters
ꢃ
;
w ¼ 1=½r2ðF 2oÞþ
2
ðapÞ þ ðbpÞꢃ; p ¼ ½maxðF 2o or 0Þ þ 2ðF 2cÞꢃ=3; a = 0.0185, b = 25.8531.