Tuning Lanthanide Ions
FULL PAPER
J=7.6, 7.6 Hz, 2H), 8.05 (d, J=8.5 Hz, 2H), 7.86 ppm (d, J=8.4 Hz,
2H); 13C NMR (50 MHz, [D6]DMSO): d=156.62, 154.89, 148.60, 145.56,
138.96, 136.42, 132.09, 129.32, 123.12, 122.52, 121.84, 118.73 ppm; elemen-
tal analysis calcd (%) for C23H14BrN11·2.8H2O: C 48.06, H 3.44, N 26.81;
found: C 47.90, H 3.09, N 26.71.
(m, 4H); 13C NMR (50 MHz, [D6]DMSO): d=165.81, 154.85, 154.09,
147.95, 143.13, 139.56, 138.82, 125.36, 124.39, 122.92, 122.79 ppm; elemen-
tal analysis calcd (%) for C12H8N6O2·1.2H2O: C 49.73, H 3.62, N 28.99;
found: C 49.81, H 3.48, N 28.69.
Synthesis of the [Ln(L1)2]NHEt3 complexes (Ln=Eu, Tb, Nd): A sus-
pension of ligand L1 (92.33 mg, 0.25 mmol) in methanol (6 mL) was re-
acted with triethylamine (69.69 mL, 0.5 mmol) to obtain a colorless solu-
tion. After addition of a solution of the appropriate lanthanide triflate
(0.12 mmol) in methanol (2 mL), the resulting slightly yellow solution
was left standing at room temperature for 12 h. The [Ln(L1)2]NHEt3
complexes were obtained as white crystals, filtered, washed with a little
methanol and ether, and dried in air (yield: 41–52%).
[Eu(L1)2]NHEt3: 1H NMR (400 MHz, MeOD): d=15.51 (d, J=8.1 Hz,
4H; H5), 12.20 (t, J=7.8, 7.83 Hz, 4H; H4), 5.33 (d, J=7.8 Hz, 4H; H3),
3.10 (q, J=7.3, 7.3, 7.3 Hz, 6H; CH2), 1.21 (t, J=7.3, 7.3 Hz, 9H; CH3)
0.72 (t, J=7.5, 7.5 Hz, 2H; H4’), ꢁ0.50 ppm (d, J=7.6 Hz, 4H; H3’); MS
(ES+): m/z: 933.0 [EuL2Na2]+; elemental analysis calcd (%) for [Eu-
Synthesis of 4’-(5-bromothiophen-2-yl)-6,6’’-bis(1H-tetrazol-5-yl)-2,2’-6’-
2’’-terpyridine ligand L4:
A
mixture of compound
9
(0.633 g,
1.425 mmol), sodium azide (0.463 g, 7.12 mmol), and ammonium chloride
(0.381 g, 7.12 mmol) in anhydrous DMF (15 mL) was stirred under argon
at 1258C for 20 h. After cooling and filtering, the precipitate was treated
with dilute HCl and stirred for 1 h. The organic phase was evaporated
and the residue taken with dilute HCl, sonicated and stirred for 1 h. The
combined acidic suspensions were filtered, washed with cold water, and
dried under vacuum to give a yellow-brown powder (0.630 g, 90%).
1H NMR (200 MHz, [D6]DMSO): d=8.86 (s, 2H), 8.77 (d, J=7.2 Hz,
2H), 8.30 (d, J=6.9 Hz, 2H), 8.22 (t, J=7.6 Hz, 7.6 Hz, 2H), 7.94 (d, J=
3.8 Hz, 1H), 7.47 ppm (d, J=3.8 Hz, 1H); 13C NMR (50 MHz,
[D6]DMSO): d=154.84, 154.46, 143.02, 142.38, 142.02, 139.36, 131.91,
127.98, 122.91, 122.83, 116.90, 114.46 ppm; elemental analysis calcd (%)
for C21H12BrN11S·3.5H2O·0.2HCl: C 41.99, H 3.22, N 25.65; found: C
41.85, H 2.84, N 25.35.
ACHNUTGTER(NGNUN C17H9N11)2]NHEt3·1.25MeOH·1.5H2O: C 46.92, H 4.01, N 30.51; found:
C 46.96, H 3.86, N 30.21.
[Tb(L1)2]NHEt3: 1H NMR (400 MHz, MeOD): d=95.43 (br, 4H), 91.87
(br, 2H; H4’), 4.22 (q, J=7.0, 7.0, 7.0 Hz, 6H; CH2), 2.20 (t, J=7.0,
7.0 Hz, 9H; CH3), ꢁ4.58 (br, 4H), ꢁ67.59 (br, 4H), ꢁ140.08 ppm (br,
Synthesis
of
4’-(4-(pyridin-2-yl)phenyl)-6,6’’-bis(1H-tetrazol-5-yl)-
2,2’:6’,2’’-terpyridine ligand L5: The compound was obtained similarly to
ligand L4, starting from compound 12 (61 mg, 0.14 mmol) to give a
cream-white powder (66 mg, 91%). The compound was recrystallized
from water–ethanol. 1H NMR (200 MHz, [D6]DMSO): d=9.25 (s, 2H),
8.91 (dd, J=6.9, 1.8 Hz, 2H), 8.76 (d, J=4.3 Hz, 1H), 8.47–8.22 (m, 8H),
8.13 (d, J=7.7 Hz, 1H), 7.97 (dt, J=7.9, 7.8, 1.7 Hz, 1H), 7.44 ppm (dd,
J=6.9, 5.0 Hz, 1H); 13C NMR (50 MHz, [D6]DMSO): d=155.28, 155.11,
154.45, 154.33, 149.63, 149.36, 143.00, 139.51, 139.28, 137.64, 137.28,
127.79, 127.05, 122.93, 122.76, 122.65, 120.43, 119.09 ppm; elemental anal-
ysis calcd (%) for C28H18N12·2.8H2O·0.2C2H5OH: C 58.59, H 4.29, N
28.87; found: C 58.60, H 4.06, N 28.63.
4H);
elemental
analysis
calcd
(%)
for
[Tb(C17H9N11)2]NHEt3·5H2O·0.5CH3OH:
C
44.15,
H
4.21,
N
29.24;
found: C 44.22, H 3.83, N 28.89. (Due to the extreme paramagnetic
effect of terbium, the multiplicities of the 1H NMR spectroscopic signals
could not be determined.)
[Nd(L1)2]NHEt3: 1H NMR (400 MHz, MeOD): d=16.18 (d, J=6.3 Hz,
4H; H3’), 14.99 (brt, 2H; H4’), 11.37 (d, J=7.1 Hz, 4H; H3), 5.84 (brt,
4H; H4), 3.11 (q, J=7.3, 7.3, 7.3 Hz, 6H; CH2), 2.06 (d, J=6.4 Hz, 4H;
H5), 1.22 ppm (t, J=7.3, 7.3 Hz, 9H; CH3); elemental analysis calcd (%)
for [Nd(C17H9N11)2]NHEt3·5H2O·0.5CH3OH: C 44.72, H 4.26, N 29.63;
found: C 44.74, H 3.95, N 29.36.
Synthesis of 4’-(5’-octyl-2,2’-bithiophen-5-yl)-6,6’’-bis(1H-tetrazol-5-yl)-
2,2’:6’,2’’-terpyridine ligand L6: The compound was obtained similarly to
ligand L1, starting from compound 15 (0.190 g, 0.34 mmol) to give a
dark-red powder (214 mg, 98%). 1H NMR (200 MHz, [D6]DMSO): d=
8.97 (s, 2H), 8.86 (dd, J=7.0, 1.0 Hz, 2H), 8.35–8.23 (m, 4H), 8.10 (d, J=
3.8 Hz, 1H), 7.45 (d, J=3.7 Hz, 1H), 7.32 (d, J=3.5 Hz, 1H), 6.88 (d, J=
3.5 Hz, 1H), 2.82 (t, J=7.2, 7.2 Hz, 2H), 1.70–1.60 (m, 2H), 1.35–1.26
(m, 10H), 0.86 ppm (t, J=6.5 Hz, 6.5 Hz, 3H); 13C NMR (50 MHz,
[D6]DMSO): d=155.06, 154.49, 154.32, 145.82, 143.04, 142.95, 139.49,
139.20, 138.23, 133.33, 128.42, 125.70, 124.58, 124.28, 122.78, 122.80,
116.81, 31.22, 30.95, 29.31, 28.65, 28.61, 28.43, 22.04, 13.90 ppm; elemental
analysis calcd (%) for C33H31N11S2·1.3H2O: C 59.23, H 5.06, N 23.02;
found: C 59.53, H 4.93, N 22.68.
Synthesis of the [Ln(L2)2]NHEt3 complexes (Ln=Eu, Tb, Nd): The pro-
cedure is similar to the one used for the synthesis of [Ln(L1)2]NHEt3
(yield: 51–72%).
[Eu(L2)2]NHEt3: 1H NMR (400 MHz, MeOD): d=11.30 (d, J=7.2 Hz,
4H; H5), 9.81 (t, J=7.7, 7.7 Hz, 4H; H4), 7.10 (d, J=7.8 Hz, 4H; H3),
5.46 (t, J=7.6, 7.6 Hz, 2H; H4’), 5.01 (d, J=7.7 Hz, 4H; H3’), 3.06 (q, J=
7.3, 7.3, 7.3 Hz, 6H; CH2), 1.20 ppm (t, J=7.3, 7.3 Hz, 9H; CH3); MS
(ES+): m/z: 793.3 [Eu(HL)2]+; elemental analysis calcd (%) for
C40H34EuN7O8·3.75H2O: C 50.03, H 4.36, N 10.21; found: C 50.05, H
4.15, N 10.26.
[Tb(L2)2]NHEt3: 1H NMR (400 MHz, MeOD): d=13.23 (br, 6H; CH2),
12.51 (br, 2H; H4’), 9.50 (br, 9H; CH3), ꢁ2.72 (br, 4H), ꢁ51,73 (br, 4H),
ꢁ58.75 (br, 4H), ꢁ90.18 ppm (br, 4H); elemental analysis calcd (%) for
C40H34TbN7O8·0.7MeOH·1.6H2O: C 51.48, H 4.24, N 10.31; found: C
51.38, H 4.06, N 10.30. (Due to the extreme paramagnetic effect of terbi-
um, the multiplicities of the 1H NMR spectroscopic signals could not be
determined.)
[Nd(L2)2]NHEt3: 1H NMR (400 MHz, MeOD): d=11.37 (d, J=7.9 Hz,
4H; H3’), 10.61 (t, J=7.5, 7.5 Hz, 2H; H4’), 9.90 (d, J=7.8 Hz, 4H; H3),
7.28 (t, J=7.4, 7.4 Hz, 4H; H4), 5.22 (d, J=7.2 Hz, 4H; H5), 3.20 (q, J=
7.3, 7.3, 7.3 Hz, 6H; CH2), 1.29 ppm (t, J=7.3, 7.3 Hz, 9H; CH3); ele-
mental analysis calcd (%) for C40H34NdN7O8·3H2O: C 51.16, H 4.29, N
10.44; found: C 51.22, H 4.12, N 10.37.
Synthesis of 6,6’-bis(1H-tetrazol-5-yl)-2,2’-bipyridine ligand L7: The com-
pound was obtained similarly to ligand L1, starting from compound 18
(0.412 g, 2 mmol) to give
a
white powder (0.449 g, 77%). 1H NMR
(200 MHz, [D6]DMSO): d=9.00 (p, J=4.0, 4.0, 4.0, 4.0 Hz, 2H), 8.33–
8.31 ppm (m, 4H); 13C NMR (50 MHz, [D6]DMSO): d=154.61, 143.15,
139.45, 123.12, 123.03 ppm; elemental analysis calcd (%) for
C12H8N10·0.2H2O: C 48.72, H 2.86, N 47.34; found: C 48.82, H 2.91, N
47.16.
Synthesis of 6’-(1H-tetrazol-5-yl)-2,2’-bipyridine-6-carboxylic acid ligand
L8: A mixture of compound 25 (0.682 g, 2.69 mmol), sodium azide
(0.875 g, 13.45 mmol), and ammonium chloride (0.720 g, 13.45 mmol) in
anhydrous DMF (25 mL) was stirred under argon for 44 h at 1358C.
After cooling, the inorganic salts were filtered and the solvent removed
under reduced pressure. After addition of dilute HCl, the resulting sus-
pension was stirred for 1 h, then the precipitate was filtered, washed with
cold water, and dried, giving 0.483 g intermediate. The product was dis-
solved in an aqueous molar solution of potassium hydroxide (10 mL,
6 equiv) and heated at reflux overnight. After addition of dilute HCl
(down to pHꢀ2), the resulting suspension was stirred for 1 h, filtered
and the precipitate washed with cold water and dried under vacuum to
give a white product (0.425 mg, 59%). 1H NMR (200 MHz, [D6]DMSO):
d=9.04 (d, J=7.3 Hz, 1H), 8.74 (dd, J=6.7, 2.0 Hz, 1H), 8.32–8.15 ppm
Synthesis of the [Ln(L3)2]NHEt3 complexes (Ln=Eu, Tb): The proce-
dure is similar to the one used for the synthesis of [Ln(L1)2]NHEt3
(yield: 67–78%).
[Eu(L3)2]NHEt3: 1H NMR (400 MHz, MeOD): d=15.70 (d, J=8.0 Hz,
4H; H5), 12.27 (t, J=7.9, 7.9 Hz, 4H; H4), 6.06 (d, J=8.9 Hz, 4H; HPh3),
5.40 (d, J=7.8 Hz, 4H; H3), 4.08 (d, J=9.0 Hz, 4H; HPh2), 3.17 (q, J=
7.3, 7.3, 7.3 Hz, 6H; CH2), 1.28 (t, J=7.3, 7.3 Hz, 9H; CH3), ꢁ0.30 ppm
(s,
4H;
H3’);
elemental
analysis
calcd
(%)
for
C52H40Br2EuN23·1MeOH·3H2O: C 45.97, H 3.64, N 23.26; found: C
46.03, H 3.26, N 23.15.
Chem. Eur. J. 2009, 15, 9458 – 9476
ꢁ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
9473