X.-Q. Song et al. / Journal of Solid State Chemistry 218 (2014) 202–212
203
2
. Experimental
added dropwise in 30 min and the resulting solution stirred and
heated to reflux for 12 h. After cooling down, inorganic salts were
separated by filtration and the solvent removed from the filtrate
under reduced pressure. The pure product was obtained using
chromatography on silica gel. Chromatography (10–60% ethyl acet-
ate in petroleum ether gradient). Yield: 87%. Mp: 158–159 1C.
2.1. Materials and instrumentation
Furfuryllamine and 1,4-xylene was obtained from Alfa Aesar Co.
Other commercially available chemicals were of analytical grade
and were used without further purification. The lanthanide
nitrates [16] were prepared according to the literature method.
Carbon, nitrogen and hydrogen analyses were performed using
an EL elemental analyzer. Melting points were determined on a
Kofler apparatus. Infrared spectra (4000–400 cm ) were obta-
ined with KBr discs on a Therrno Mattson FTIR spectrometer.
Powder X-ray diffraction patterns (PXRD) were determined on
Analytical data for C34
Found: C, 72.68; H, 5.69 N, 4.85. IR (KBr,
32 2 6
H N O , Calcd: C, 72.32; H, 5.71; N, 4.86;
ꢀ
1
υ, cm ): 3386 (s), 2923
(m), 1648 (vs), 1597 (s), 1537 (vs), 1480 (m), 1446 (m), 1293 (m),
1221 (s), 1004 (m), 960 (w), 750 (s) (br, broad; w, weak; m, medium;
ꢀ
1
1
s, strong; vs, very strong) H NMR (CDCl
3
, 400 MHz, ppm):
δ 2.24
(s, 6H, –CH
3
), 4.42 (t, 4H, –CH
2
–), 5.25 (s, 4H, –CH –), 5.80 (d, 2H,
2
Ar–H), 6.13 (t, 2H, Ar–H), 7.09–7.54 (m, 8H, ArH), 7.53 (t, 2H), 8.11
a Rigaku-D/Max-II X-ray diffractometer with graphite-mono-
chromatized Cu-K
CDCl
(s, 2H, –NH), 8.31 (d, 2H, ArH). ESI-MS: m/z 547.7 (MþHþ).
1
α
radiation. H NMR spectra were recorded in
3
solution at room temperature on a Bruker 400 instrument
2.3. Synthesis of the complexes
operating at a frequency of 400 MHz and referenced to tetra-
methylsilane (0.00 ppm) as an internal standard. Chemical shift
multiplicities are reported as s¼singlet, d¼doublet, t¼triplet and
m¼multiplet. Fluorescence measurements of the well grinded
thick solid samples were made on FLS920 of Edinburgh Instru-
[
Pr
2
(NO
3
)
6
L
3
]
1
(1). 56.4 mg (0.1 mmol) L and 43.5 mg (0.1 mmol)
Pr(NO
3
)
3
ꢁ 6H
2
O were dissolved in a hot ethyl acetateþmethanolþ
acetone (v: v- v¼10:1:1) solution to make a concentrated solution.
Then the flask was cooled, and the mixture was filtered into a sealed
III
ment. The 77 K solution-state phosphorescence spectra of the Gd
1
0–20 ml glass vial for crystallization at room temperature. After about
two weeks, pale green single crystals of 1 suitable for crystal analysis
were obtained (yield: 78.7 mg, 67% based on Pr(NO O. Analy-
tical data (%), Calcd: C, 52.18; H, 4.12; N, 7.16; Found: C, 51.98; H, 4.09;
N, 7.12. IR (KBr, υ, cm ): 3342 (m), 2925 (m), 1611 (s), 1560 (m), 1484
complex was recorded with solution samples (a 1:1 ethyl acetate–
MeOH (v/v) mixture) loaded in a quartz tube inside a quartz-
walled optical Dewar flask filled with liquid nitrogen in the
phosphorescence mode on a Hitachi F-7000 spectro photometer
and equipped with a xenon lamp as the excitation source (front-
facemode) [17]. Samples were placed between two quartz cover
slips and the excitation and emission slit of 1.0 nm or 2.5 nm were
used. Quantum yields were determined by an absolute method
3
)
3
ꢁ 6H
2
ꢀ1
(
s), 1295 (s), 1223 (m), 1029 (m), 985 (m), 814 (w), 754 (m).
[Nd(NO L(CH O)](C O)} (2). The procedure was the
same as that for 1 using Nd(NO O instead. Pale purple
ꢁ 6H
single crystals of 2 were formed after three weeks (yield: 63.2 mg,
{
3
)
3
4
3
H
6
1
3
)
3
2
[18] using an integrating sphere on FLS920 of Edinburgh Instru-
6
5% based on Nd(NO
H, 4.35; N, 7.20; Found: C, 45.78; H, 4.38; N, 7.16. IR (KBr, υ, cm ):
3
)
3
ꢁ 6H
2
O. Analytical data (%), Calcd: C, 45.67;
ment. The luminescence decays were recorded using a pumped
dye laser (Lambda Physics model FL2002) as the excitation source.
The nominal pulse width and the line width of the dye-laser
ꢀ1
3
1
336 (m), 2925 (m), 1611 (s), 1561 (m), 1486 (s), 1303 (s), 1223 (m),
031 (m), 988 (m), 815 (w), 754 (m).
[Eu(NO L(CH O)](C O)} (3). The procedure was the same
as that for 1 using Eu(NO O instead. Colorless single
ꢁ 6H
crystals of 3 were formed after three weeks (yield: 58.8 mg, 60%
ꢀ
1
output were 10 ns and 0.18 cm , respectively. The emission of
the sample was collected by two lenses in a monochromator
{
3
)
3
4
3
H
6
1
3
)
3
2
(
WDG30), detected by a photomultiplier and processed by a
Boxcar Average (EGG model 162) in line with a microcomputer.
Reported quantum yields and luminescence lifetimes are averages
of at least three independent determinations. The estimated errors
for quantum yields and luminescence lifetimes are 10%.
based on Eu(NO
3
)
3
ꢁ 6H
2
O. Analytical data (%), Calcd: C, 45.31; H,
ꢀ1
4
3
.32; N, 7.14; Found: C, 45.48; H, 4.29; N, 7.16. IR (KBr, υ, cm ):
350 (m), 2924 (m), 1616 (s), 1557 (m), 1490 (s), 1291 (s), 1227 (m),
1
030 (m), 985 (m), 815 (w), 758 (m).
Gd (NO (4). The procedure was the same as that for
1 using Gd(NO O instead. Colorless micro crystals of 4 were
ꢁ 6H
formed after two weeks (yield: 73.7 mg, 62% based on Gd(NO 6H O.
Analytical data (%), Calcd: C, 51.47; H, 4.06; N, 7.06; Found: C, 51.48; H,
[
2
3 6 3 1
) L ]
2.2. Synthesis of the ligand
3
)
3
2
3
)
3
·
2
The synthetic route for the ligand (L) is shown in Scheme 1.
-Furfurylsalicylamide [19] and 1,4-bis(bromomethyl)-2,5-dimethyl-
ꢀ
1
2
4.07; N, 7.05. IR (KBr,
1503 (s), 1308 (s), 1223 (m), 1034 (m), 985 (m), 815 (w), 754 (m).
[Tb (NO (5). The procedure was the same as that for 1 using
Tb(NO O instead. Colorless micro crystals of 5 were formed
ꢁ 6H
after two weeks (yield: 77.4 mg, 65% based on Tb(NO O.
ꢁ 6H
Analytical data (%), Calcd: C, 51.39; H, 4.06; N, 7.05; Found: C, 51.34;
υ, cm ): 3334 (m), 2926 (m), 1611 (s), 1564 (m),
benzene [20] was prepared according to the literature procedure.
To a solution of 2-furfurylsalicylamide (2.28 g, 10.5 mmol) in dry
2
3 6 3 1
) L ]
acetone was added 1.52 g (11 mmol) dried K
was stirred for 30 min at room temperature, 1.45 g (5 mmol) 1,4-bis
bromomethyl)-2,5-dimethyl-benzene in 20 ml of dry acetone was
2 3
CO , and the mixture
3
)
3
2
3
)
3
2
(
Scheme 1. The synthetic route of the ligand L.