464
L. Wang et al. / C. R. Chimie 15 (2012) 463–470
1–3 with the general formula Ar1(CH = N–N = HC)Ar2
(Ar1 = Ar2 = 2-OH-3,5-tBu2C6H2 (1), Ar1 = Ar2 = 2-BrC6H4
(2), Ar1 = ortho-C6H4(NHC6H3-Me2-2,6), Ar2 = 2-FC6H4
(3)). The luminescent properties of these benzaldazine
derivatives 1–3 were studied both in solution and in the
solid state. The effect of the functional groups on molecular
packing and fluorescent properties in the solid state and
solution with different solvents was also investigated.
2.4. Synthesis of ortho-C6H4F(CH = N–N = HC)C6H4(NHC6H3-
Me2-2,6)-ortho (3)
Compound ortho-C6H4F(CH = N–N = HC)C6H4F-ortho
was synthesized by the similar procedure as compound
1. Hydrazine hydrate (0.05 g, 1.00 mmol) and 2-fluoro-
benzaldehyde (0.25 g, 2.00 mmol) in ethanol afforded
compound ortho-C6H4F(CH = N–N = HC)C6H4F-ortho as
yellow solid. Yield: 0.24 g (98%). M.p. 132.3–132.8 8C.
Anal. Calcd. for C14H10N2F2 (244.24): C 68.85, H 4.13, N
11.47. Found: C 68.94, H 4.25, N 11.30. 1H NMR (300 MHz,
2. Experimental
CDCl3):
d 8.93 (s, 2H), 8.13 (t, J = 6.9 Hz, 2H), 7.48–7.42 (m,
2.1. General
2H), 7.23–7.10 (m, 4H) ppm. 13C NMR (75 MHz, CDCl3):
d
158.8, 155.4, 150.6, 150.6, 127.8, 127.7, 122.5, 122.5,
119.3, 119.2, 116.6, 116.4, 110.9, 110.6 ppm. IR (KBr,
All solvents and reagents were commercially obtained
and used as received. 3,5-Di-tert-butyl-2-hydroxyben-
zaldehyde was synthesized according to the literature
method [15]. 1H NMR and 13C NMR spectra were
measured using a Varian Mercury-300 NMR spectrome-
ter. IR spectra were recorded on a Nicolet Impact 410 FTIR
spectrometer using KBr pellets. The elemental analyses
were performed on a Perkin-Elmer 2400 analyzer. UV–vis
absorption spectra were recorded on an UV-3100
spectrophotometer. Fluorescent measurements were
carried out on a RF-5301PC. All melting points were
determined by an X-5 micr-melting point apparatus and
are uncorrected.
cmꢀ1):
653, 462.
y 1627, 1483, 1457, 1233, 1096, 959, 814, 753,
A solution of n-BuLi (1.40 mL, 1.90 mmol) in n-hexane
was added to a solution of 2,6-dimethylaniline (0.22 mL,
1.80 mmol) in THF (20 mL) at 0 8C. The mixture was
allowed to warm to room temperature and stirred
for additional 2 h. The resulting solution was transferred
into a solution of ortho-C6H4F(CH = N-N = HC)C6H4F-ortho
(0.40 g, 1.60 mmol) in THF (10 mL) at 25 8C. After stirring
for 2 h, the reaction was quenched with H2O (20 mL). The
layers were separated and the water layer was washed
with Et2O (2 ꢂ 30 mL). The combined organic phase was
dried over anhydrous MgSO4 for 2 h, and filtered. The
organic phase was evaporated to dryness to give the crude
product as brown oil. The crude product was purified by
column chromatography on silica gel with ethyl acetate/
petroleum ether (1:5 in volume) as eluent to give the pure
product as yellowish crystals. Yield: 0.48 g (85%). M.p.:
117.6–118.3 8C. Anal. Calcd. for C22H20N3F (345.41): C
76.50, H 5.84, N 12.17. Found: C 76.42, H 5.90, N 12.13. 1H
2.2. Synthesis of 3,5-di-tBu-2-OHC6H4(CH = N–N = HC)C6H4-
OH-2-tBu-di-5,3 (1)
3,5-di-tert-butyl-2-hydroxybenzaldehyde (0.40 g, 2.00
mmol) was added to hydrazine hydrate (0.05 g, 1.00 mmol)
in 5 mL ethanol. The resulting bright yellowish mixture
was refluxed for 2 h. Upon cooling the reaction mixture
to room temperature, yellow solids were precipitated.
The obtained solid product was washed with cold
ethanol, then dried in vacuo to give the desired product
in excellent yield. Yield: 0.45 g (96%). M.p. 219.2–
221.4 8C. Anal. Calcd. for C30H44N2O2 (464.68): C 77.54,
H 9.54, N 6.03. Found: C 77.48, H 9.62, N 6.10. 1H NMR
NMR (300 MHz, CDCl3):
d 9.80 (s, 1H), 8.89 (s, 1H), 8.86 (s,
1H), 8.13 (t, J = 6.6 Hz, 1H), 7.50–7.33 (m, 2H), 7.24–7.05
(m, 6H), 6.72 (t, J = 7.4 Hz, 1H), 6.26 (d, J = 8.3 Hz, 1H), 2.24
(s, 6H) ppm. 13C NMR (75 MHz, CDCl3):
d 166.1, 153.8,
136.5, 134.4, 132.4, 132.2, 132.1, 128.2, 127.4, 127.3, 126.2,
124.2, 124.1, 115.8, 115.8, 115.6, 114.9, 111.6, 18.2. IR (KBr,
(300 MHz, CDCl3):
J = 2.0 Hz, 2H), 7.17 (d, J = 2.0 Hz, 2H), 1.47 (s, 18H), 1.32
(s, 18H) ppm. 13C NMR (75 MHz, CDCl3):
165.2, 156.8,
141.3, 136.9, 128.2, 126.9, 116.7, 31.4, 29.4 ppm. IR (KBr,
cmꢀ1):
2960, 1623, 1592, 1439, 1390, 1362, 1251,
d
11.89 (s, 2H), 8.76 (s, 2H), 7.46 (d,
cmꢀ1):
754, 465.
y 2922, 1622, 1576, 1456, 1318, 1198, 1099, 768,
d
2.5. X-ray structure determinations of 1, 2 and 3
y
1201, 1173, 963, 717.
The block-shaped single yellow crystals for X-ray
analysis of 1 and 2 were obtained from a tetrahydrofuran
solution and diethyl ether solution upon cooling to 0 8C,
2.3. Synthesis of ortho-C6H4Br(CH = N–N = HC)C6H4Br-ortho
(2)
respectively. Single crystals of 3 suitable for X-ray
structural analysis were obtained from slow evaporation
of a methanol solution. Diffraction data were collected at
226(2) K (for 1) or at 293 K (for 2 and 3) on a Bruker Smart
Similarly, 2-bromo-benzaldehyde (0.37 g, 2.00 mmol)
and hydrazine hydrate (0.05 g, 1.00 mmol) in ethanol
afforded compound 2 as yellow solid. Yield: 0.34 g (94%).
M.p. 173.2–173.4 8C. Anal. Calcd. for C14H10N2Br2 (366.05):
C 45.94, H 2.75, N 7.65. Found: C 45.98, H 2.82, N 7.54. 1H
diffractometer equipped with graphite-monochromated
˚
Mo-K
a radiation (l = 0.71073 A) for all compounds. The
structures were solved by direct methods [16] and refined
by full-matrix least-squares on F2. All non-hydrogen atoms
were refined anisotropically and the hydrogen atoms were
included in idealized position. All calculations were
performed using the SHELXTL [17] crystallographic
software packages. Details of the crystal data, data
NMR (300 MHz, CDCl3):
2H), 8.20 (d, J = 1.8 Hz, 2H), 7.42–7.29 (m, 4H) ppm. 13C
NMR (75 MHz, CDCl3): 161.4, 133.2, 132.7, 132.4, 128.6,
127.6, 125.8 ppm. IR (KBr, cmꢀ1):
1613, 1559, 1431,
1316, 1270, 1024, 953, 751, 640, 439.
d 9.02 (s, 2H), 8.23 (d, J = 1.8 Hz,
d
y