Ruthenium() Complexes with Substituted Bipyridine and Phenylpyridine Ligands
FULL PAPER
compound was used in the next step without further purification
(triethyl phosphite could not be totally eliminated). 1H NMR
(CDCl3): δ = 8.55 (s, 1 H), 7.95 (m, 2 H), 7.70 (m, 2 H), 7.42 (m,
was carried out on alumina (3% MeOH in CH2Cl2) to yield the
pure complex (15 mg, 24%). 1H NMR (CD3COCD3): δ = 8.78 (td,
J = 8.2 and 1.1 Hz, 1 H, H36), 8.68 (ddd, J = 8.1, 1.1 and 0.6 Hz,
3 H), 4.05 (m, 4 H), 3.14 (d, JH,P = 21.6 Hz, 2 H), 1.26 (t, J = 1 H, H33), 8.62 (ddd, J = 8.2, 1.3 and 0.8 Hz, 1 H, H23), 8.60
7.2 Hz, 6 H) ppm.
(ddd, J = 8.3, 1.2 and 0.8 Hz, 1 H, H26), 8.21 (d, J = 8.8 Hz, 2 H,
H16, H18), 8.24–8.17 (m, 3 H, H11, H37, H9), 8.16 (ddd, J = 5.7,
1.5 and 0.7 Hz, 1 H, H30), 8.10 (ddd, J = 5.4, 1.5 and 0.8 Hz, 1
H, H39), 8.06 (ddd, J = 5.8, 1.4 and 0.8 Hz, 1 H, H29), 8.00–7.90
(m, 6 H, H22, H32, H8, H5, H27, H20), 7.71 (d, J = 8.9 Hz, 2 H,
H15, H19), 7.64 (ddd, J = 7.6, 5.4 and 1.2 Hz, 1 H, H38), 7.42–
7.38 (m, 3 H, H21, H31, H28), 7.29 (d, J = 16.4 Hz, 1 H, H13),
7.21 (d, J = 16.4 Hz, 1 H, H12), 6.92 (dt, J = 7.2 and 1.2 Hz, 1 H,
H4), 6.85 (dt, J = 7.2 and 1.3 Hz, 1 H, H3), 6.52 (dd, J = 7.4 and
1 Hz, 1 H, H2) ppm. 13C NMR (CD3COCD3): δ = 194.27 (C1),
167.39 (C7), 157.90 (C34), 157.09 (C24), 156.80 (C25), 155.34
(C35), 154.27 (C30), 150.56 (C29), 150.04 (C20) 149.95 (C8), 149.23
(C39), 147.10 (C17), 145.26 (C6), 143.34 (C14), 136.59 (C37),
135.37 (C2), 135.19 (C32), 134.04 (C22), 133.77 (C27), 132.22 (C9),
131.17 (C10), 128.62 (C3), 128.46 (C12), 127.98 (C13), 127.37
(C38), 127.27 (C15, C19), 126.57 (C21), 126.40 (C31), 126.27 (C28),
124.85 (C5), 123.97 (C16, C18), 123.63 (C33), 123.41 (C36), 123.09
(C26), 123.08 (C23), 120.95 (C4), 118.39 (C11) ppm. The metathe-
sis was carried out as follows: the complex with the triflate counter-
ion was dissolved in the minimum amount of methanol then a satu-
rated aqueous solution of NH4PF6 was added until no more pre-
cipitation occurred. The precipitate was filtered off, rinsed with dis-
tilled water and dried under vacuum. C39H29F6N6O2PRu (859.7) +
H2O: calcd. C 52.41, H 3.50, N 9.40; found C 52.38, H 3.30, N
9.12. FAB-MS: m/z = 715 [M–PF6]+.
[Ru(bpy)2(L2)][PF6]2: L2 (48 mg, 0.158 mmol) was dissolved in
EtOH (25 mL) under N2 and the mixture heated to reflux.
[Ru(bpy)2Cl2] (85 mg, 0.158 mmol) was then added and the mixture
refluxed for 3 h. After cooling in an ice bath, addition of NH4PF6
(saturated solution in water) led to the precipitation of the complex.
The orange precipitate was filtered off, rinsed with water and di-
ethyl ether, and dried in vacuo (115 mg). The compound was ob-
tained by two successive chromatographic purifications on alumina
(CH3CN) and finally crystallization from acetone, which yielded
the pure, brick-red complex (80 mg, 50%).1H NMR (CD3COCD3):
δ = 8.88–8.82 (m, 6 H, H8, H5, H26, H23, H33, H36), 8.60 (dd, J
= 8.5, 1.9 Hz, 1 H, H9), 8.30–8.06 (m, 7 H, H11, H4, H27, H25,
H32, H37, H39), 8.24 (d, J = 9 Hz, 2 H, H16, H18), 8.11 (dd, J =
5.6, 7 Hz, 1 H, H2), 8.09–8.06 (m, 3 H, H29, H20, H30), 7.76 (d,
J = 8.8 Hz, 2 H, H15, H19), 7.64–7.58 (m, 5 H, H3, H31, H38,
H21, H28), 7.57 (d, J = 16.4 Hz, 1 H, H12), 7.21 (d, J = 16.5 Hz, 1
H, H13) ppm. 13C NMR (CD3COCD3): δ = 157.33, 157.24, 157.21,
157.04, 156.30, 152.07 (C11), 151.92 and 151.83 and 151.75 (C2,
C29, C20, C30), 151.05, 147.62, 142.51, 138.09, and 138.00 (C37,
C32, C25, C27), 136.53, 133.84 (C9), 132.01 (C12), 127.93, 127.88,
127.86, 127.84 (C15, C19), 127.75, 127.04 (C13), 124.60, 124.50,
124.48, 124.44, 124.35, 124.04, 114.38 ppm. C38H29F12N7O2P2Ru
(1006.7): calcd. C 45.34, H 2.90, N 9.74; found C 45.19, H 2.77, N
9.49. FAB-MS: m/z = 862 [M–PF6]+, 717 [M–2PF6]+.
Diethyl (2,2Ј-Bipyridin-5-yl)methylphosphonate (3b): Same pro-
cedure as for the synthesis of 3a, starting from 2b and using 98%
CH2Cl2/2% CH3OH as eluent for the two chromatographic separa-
tions. Some traces of triethyl phosphite remained and the com-
1
pound was used without any further purification (Yield: 76%). H
NMR (CDCl3): δ = 8.66 (d, J = 4.2 Hz, 1 H), 8.56 (s, 1 H), 8.36
(d, J = 3.6 Hz, 1 H), 8.33 (d, J = 3.8 Hz, 1 H), 7.80 (m, 2 H), 7.28
(m, 1 H), 4.08 (q, J = 7 Hz, 4 H), 3.18 (d, JH,P = 22 Hz, 2 H), 1.35
(t, J = 6.8 Hz, 6 H) ppm.
5-(p-Nitrostyryl)-2-phenylpyridine (HL1): In a Schlenk flask, 3a
(348 mg, 1.14 mmol) was dissolved in THF (21 mL) and cooled in
an ice bath. n-Butyllithium (1.6 in hexane; 0.72 mL, 1.15 mmol)
was added dropwise and the solution was stirred at room tempera-
ture for 1 h. A THF solution (6 mL) of p-nitrobenzaldehyde
(174 mg, 1.15 mmol) was then added slowly and the color changed
from yellow to brown. The mixture was refluxed for 3 h. After cool-
ing to room temperature, the mixture was hydrolyzed with water
(10 mL). The precipitate was filtered off, washed with diethyl ether,
and purified by column chromatography on alumina (80% CH2Cl2/
20% n-pentane). The product was recovered as a lemon-yellow
1
powder (200 mg, 37% yield). H NMR (CDCl3): δ = 8.86 (d, J =
2.1 Hz, 1 H, H6), 8.27 (d, J = 8.8 Hz, 2 H, H11, H13), 8.07 (dd, J
= 8.7 and 1.4 Hz, 2 H, H2Ј, H6Ј), 7.98 (dd, J = 8.3 and 2.3 Hz, 1
H, H4), 7.81 (d, J = 8.3 Hz, 1 H, H3), 7.70 (d, J = 8.8 Hz, 2 H,
H10, H14), 7.53 (dd, J = 7.6 and 7.1 Hz, 2 H, H3Ј, H5Ј), 7.47 (t,
J = 7.3 Hz, 1 H, H4Ј), 7.31 (d, J = 16.3 Hz, 1 H, H7), 7.26 (d, J =
16.3 Hz, 1 H, H8) ppm. 13C NMR (CDCl3): δ = 155.22 (C2),
148.96 (C6), 147.08 (C12), 143.18 (C9), 138.59 (C1Ј), 133.87 (C4),
130.36 (C5), 129.41 (C4Ј), 129.35 (C7), 128.91 (C5Ј), 127.89 (C8),
127.10 (C10, C14), 126.89 (C6Ј), 124.27 (C11, C13), 120.48 (C3)
ppm. C19H14N2O2 (302.3): calcd. C 75.48, H 4.67, N 9.27; found
C 75.14, H 4.59, N 9.12. DCI MS (NH3): m/z = 303 [MH]+.
5-(p-Nitrostyryl)-2,2Ј-bipyridine (L2): According to the procedure
described above for the synthesis of HL1, 3b yielded compound L2
(29% yield) after purification by chromatography on alumina with
0.5% MeOH in CH2Cl2. 1H NMR (CDCl3): δ = 8.84 (d, J =
1.9 Hz, 1 H, H6), 8.73 (ddd, J = 4.7, 1.6 and 0.8 Hz, 1 H, H6Ј),
8.51 (d, J = 8.3 Hz, 1 H, H3), 8.47 (d, J = 8 Hz, 1 H, H3Ј), 8.29
(d, J = 8.9 Hz, 2 H, H11, H13), 8.06 (dd, J = 8.3 and 2.3 Hz, 1 H,
H4), 7.88 (td, J = 7.8 and 1.6 Hz, 1 H, H4Ј), 7.71 (d, J = 8.8 Hz,
2 H, H10, H14), 7.37 (ddd, J = 5.9; 4.9 and 1 Hz, 1 H, H5Ј), 7.34
(d, J = 16.5 Hz, 1 H, H7), 7.30 (d, J = 15.5 Hz, 1 H, H8) ppm. 13
C
NMR (CDCl3): δ = 155.70 (C2), 155.32 (C2Ј), 149.15 (C6Ј), 148.56
(C6), 147.16 (C12), 143.07 (C9), 137.25 (C4Ј), 133.99 (C4),
131.99(C5) 129.27 (C7), 128.50 (C8), 127.18 (C10, C14), 124.28
(C11, C13), 124.05 (C5Ј), 121.36 (C3Ј), 121.22 (C3) ppm.
C18H13N3O2 (303.3): calcd. C 71.28, H 4.32, N 13.85; found C
70.78, H 3.94, N 13.53. EI-MS: m/z = 303 [M]+.
Crystallographic Studies: Single crystals of [Ru(bpy)2(L1)][PF6]
suitable for X-ray structure determination were grown by slow dif-
fusion of diethyl ether into a concentrated solution of the complex
in acetonitrile. Data were collected at 180 K with a Stoe Imaging
Diffraction System (IPDS) equipped with a graphite-monochro-
mated Mo-Kα radiation source (λ = 0.71073 Å) and an Oxford
Cryosystems Cryostream Cooler Device. Empirical absorption cor-
rections were applied (Tmin = 0.811, Tmax = 0.963).[33] The structure
was solved by direct methods using SIR92,[34] and refined by means
of least-squares procedures on F2 with the aid of the program
[Ru(bpy)2(L1)][PF6]: [Ru(bpy)2Cl2] (40 mg, 0.073 mmol) and AgOTf
(41 mg, 0.16 mmol) were added to a hot solution of HL1 (110 mg,
0.36 mmol) in MeOH/CH2Cl2 (1:1, 10 mL) and the mixture was
heated at 60 °C for 1 h. After cooling, the AgCl precipitate was
filtered through glass fiber. The filtrate was concentrated and the
crude product was purified by chromatography on alumina using
two eluents: 0.5% MeOH in CH2Cl2 to recover the unreacted ex-
cess of ligand, then 3% MeOH in CH2Cl2 to isolate a dark-violet
complex. A second chromatographic purification of this complex
Eur. J. Inorg. Chem. 2006, 3105–3113
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