Molecular ion found at 427.2349 (12C24 H2714N8 requires 427.2358,
error of 2.2 ppm).
1
Experimental
Radiochemical experiments were performed at the CEA (France)
as previously described.7,8 The nitric acid stability test was
performed at the CEA by shaking solutions of the extractants
(0.01 M) and N,Nꢀ-dimethyl-N,Nꢀ-dioctyl-2-(2-hexyloxy-ethyl)-
malonamide (0.25 M, DMDOHEMA) in octanol nitric acid
Synthesis of C4-BTBP
2,2ꢀ-Bipyridine-6,6ꢀ-dicarboxbisamidrazone (1) (810 mg) was re-
acted with of decane-5,6-dione (1.97 g) in tetrahydrofuran
(175 mL) as described above so furnishing C4-BTBP (811 mg,
50%) after recrystallisation from hot ethanol. Found: C, 71.1; H,
7.8; N, 20.7%; C24H26N8 requires C, 71.3; H, 7.9; N, 20.8%. dH 8.85
(2H, d, 7.1 Hz), 8.52 (2H, d, 7.8 Hz), 7.96 (2H, t, 7.9 Hz), 3.01
(4H, t, 7.7 Hz), 2.88 (4H, t, 7.7 Hz), 1.80 (8H, m), 1.45 (8H, m),
0.95 (12 H) ppm. dC 162.20 (quat), 161.62 (quat), 160.13 (quat),
156.53 (quat), 153.10 (quat), 138.37, 124.45, 123.47, 34.05 (CH2),
32.51 (CH2), 30.86 (CH2), 29.96 (CH2), 23.08 (CH2), 22.99 (CH2),
14.36 and 14.29 ppm.
(1 M) at 25 ◦C for two h. Then the mixture was allowed to stand
1
for 1 h and then the procedure was repeated. 1H, 13C–{ H} and 13
C
NMR spectra were recorded using either a Bruker AMX400 or an
Avance DPX250 instrument. Chemical shifts are reported in parts
per million downfield from tetramethylsilane. All organic reagents
were purchased from Acros or Aldrich, while inorganic reagents
were obtained from either BDH or Aldrich. Dodecane-6,7-dione
was obtained by the sequential reaction of ethyl hexanoate with
sodium/trimethylchlorosilane, aqueous hydrochloric acid and
copper(II) acetate. 3,3,6,6-Tetramethyl-cyclohexane-1,2-dione was
obtained by the bromine oxidation of 3,3,6,6-tetramethyl-1,2-
bis-(trimethylsilanyloxy)-cyclohexene.9 The 6,6ꢀ-bis-(5,6-dialkyl-
1,2,4-triazin-3-yl)-2,2ꢀ-bipyridines (BTBPs) were obtained from
the sequential reaction of 6,6ꢀ-dicyano-2,2ꢀ-bipyridine10 with
hydrazine11 and then with a 1,2-diketone. The overall procedure
by which the BTBPs were prepared is shown in Fig. 2. On
cooling solutions of the tetraethyl (C2-BTBP) and CyMe4-BTBP
derivatives in THF, crystals were obtained.
Synthesis of C5-BTBP
2,2ꢀ-Bipyridine-6,6ꢀ-dicarboxbisamidrazone (1) (10.50 g) was re-
acted with dodecane-6,7-dione (23.69 g) in tetrahydrofuran
(500 mL) as described above to furnish after a recrystallisation
from ethanol C5-BTBP (14.62 g, 63%). Found: C, 72.6; H, 8.6; N,
19.0%; C24H26N8 requires C, 72.7; H, 8.5; N, 18.8%. dH 8.94 (2H,
dd, 7.9 and 1.0 Hz), 8.61 (2H, dd, 7.8 and 1.0 Hz), 8.07 (2H, t,
7.9 Hz), 3.09 (4H, t, 7.7 Hz), 2.96 (4H, t, 7.7 Hz), 1.90 (4H, m),
1.50 (8H, m), 0.98 (6H, m) ppm. dC 162.19 (quat), 161.63 (quat),
160.13 (quat), 156.53 (quat), 153.12 (quat), 138.35, 124.45, 123.44,
34.29 (CH2), 32.78 (CH2), 32.10 (CH2), 32.02 (CH2), 28.47 (CH2),
27.55 (CH2), 22.93 (CH2), 22.88 (CH2), 14.39 and 14.37 ppm.
Synthesis of C6-BTBP
2,2ꢀ-Bipyridine-6,6ꢀ-dicarboxbisamidrazone (0.844 g) (1) was re-
acted with tetradecane-7,8-dione (2.44 g) in a mixture of tetrahy-
drofuran (175 mL) and triethyl amine (2.5 mL) as described above
to furnish C6-BTBP (0.689 g. 34%) (after titruration with diethyl
ether rather than recrystallisation from ethanol). Found: C, 73.8;
H, 9.0; N, 17.2%; C24H26N8 requires C, 73.8; H, 9.0; N, 17.2%.
dH 8.92 (2H, dd, 7.9 and 1.0 Hz), 8.61 (2H, dd, 7.8 and 1.0 Hz),
8.07 (2H, t, 7.9 Hz), 3.08 (4H, t, 7.7 Hz), 2.96 (4H, t, 7.7 Hz), 1.9
(4H, m), 1.4 (12 H, m), 0.93 (6H, m) ppm. dC 162.2 (quat), 161.6
(quat), 160.2 (quat), 156.5 (quat), 153.1 (quat), 138.4, 124.5, 123.5,
34.3 (CH2), 32.8 (CH2), 32.0 (CH2), 32.0 (CH2), 29.6 (CH2), 29.6
(CH2), 28.8 (CH2), 27.8 (CH2), 23.0, 14.5 ppm.
Fig. 2 Overall scheme for the synthesis of the BTBP ligands.
A typical procedure for the synthesis of a BTBP, C2-BTBP
Powdered 2,2ꢀ-bipyridine-6,6ꢀ-dicarboxbisamidrazone (1.85 g) (1)
was added to a stirred solution of hexane-3,4-dione (11.5 mL) in
tetrahydrofuran (500 mL), and the resulting mixture was heated
over 45 min to the boiling point. After boiling under reflux
(150 min), the mixture was allowed to cool. If the mixture was
Synthesis of CyMe4-BTBP
2,2ꢀ-Bipyridine-6,6ꢀ-dicarboxbisamidrazone (1) (2.01 g) was re-
acted with 3,3,6,6-tetramethyl-cyclohexane-1,2-dione (4.60 g) in
a mixture of tetrahydrofuran (250 mL) and triethylamine (7.5 mL)
as described above. The residue from the evaporation of the filtered
reaction mixture (heavy oil) was triturated with petroleum ether
(10 mL, bp 60–80 ◦C) before the crude solid (4.2 g) was collected
by filtration. This solid was treated with ethanol (75 mL), the
resulting mixture was briefly boiled before being allowed to cool.
Subsequently the solid was collected by filtration. After washing
twice with cold ethanol and three times with cold diethyl ether the
canary yellow solid (2.40 g. 60%) was dried in air. Found: C, 71.5;
H, 7.2; N◦, 20.7%; C24H26N8 requires C, 71.9; H, 7.2; N, 21.0%. Mp
261–262 C. dH 8.96 (2H, dd, 7.9 and 1.0 Hz), 8.55 (2H, dd, 7.8
R
cloudy, it was filtered through Celiteꢀ before all volatile matter
was removed under vacuum. To the residue was added ethanol
(40 mL), and the resulting mixture was boiled briefly before being
allowed to cool. The solid product (1.96 g, 67%) was then collected
by filtration, washed with ethanol and then diethyl ether, and was
then dried in air. Found: C, 67.1; H, 6.1; N, 26.1%; C24H26N8
requires C, 67.6; H, 6.1; N, 26.3%. dH 8.85 (2H, dd, 7.9 and
0.9 Hz), 8.54 (2H, dd, 7.8 and 0.9 Hz), 7.99 (2H, dd, 7.9 and
7.8 Hz), 3.05 (4H, q, 7.5 Hz), 2.96 (4H, q, 7.4 Hz), 1.40 (12H, m)
ppm. dC 162.77 (quat), 161.77 (quat), 160.61 (quat), 156.53 (quat),
153.10 (quat), 138.38, 124.47, 123.47, 27.51 (CH2), 26.12 (CH2),
12.71 and 11.60 ppm. MS(CI+) MH + 427, 317 and 207 m/z.
1646 | Dalton Trans., 2006, 1645–1653
This journal is
The Royal Society of Chemistry 2006
©