Organometallics
Article
phases were dried over MgSO4 and filtered off. Crude product was
isolated after the removal of solvent under reduced pressure, which
was further dissolved in acetone (10 mL) and precipitated as yellow
solids by stirring with NH4PF6 (0.14 g, 0.83 mmol) for 2 h. The yellow
precipitate was filtered, dried, and further purified by silica gel column
chromatography, using DCM/MeOH (20:1, v/v) as eluent, to yield a
dark yellow powder (0.05 g, 0.06 mmol). Yield: 14%. 1H NMR
(acetonitrile-d3): δ 8.10 (t, JH−H = 8.2 Hz, 2H, py-C4H), 7.90 (d, JH−H
= 2.2 Hz, 2H, imidazole-H), 7.85 (d, JH−H = 8.2 Hz, 2H, py-C3H),
7.63 (d, JH−H = 7.5 Hz, 2H, py-C5H), 7.33 (d, JH−H = 1.9 Hz, 2H,
imidazole-H), 7.03 (d, JH−H = 2.24 Hz, 2H, imidazole-H), 6.92 (d,
JH−H = 1.9 Hz, 2H, imidazole-H), 5.40 (d, JH−H = 15.0 Hz, 2H, NCH-
py), 4.86 (d, JH−H = 15.0 Hz, 2H, NCH-py), 3.02 (m, 2H, butyl-H),
2.71 (m, 2H, butyl-H), 0.62 (m, 32 H, butyl-H) ppm. 13C NMR
(acetonitrile-d3): δ 194.9, 181.9, 156.4, 155.6, 138.4, 123.7, 122.4,
121.1, 120.9, 116.6, 110.9 (Ar-C); 54.2 (CH2); 48.7, 47.5, 32.2, 31.9,
19.7, 19.2, 12.7, 12.7 (aliphatic chain-C) ppm. Mass (MALDI): m/z
775 [M − 1]+. Anal. Calcd for C40H54F12N10P2Ru: C 45.07, N 13.14,
H 5.11. Found: C 45.12, N 13.15, H 5.43.
L2H2·Br2. To a dry acetonitrile solution (50 mL) of 2-((imidazol-1-
yl)methyl)-6-(benzimidazol-1-yl)pyridine (1.0 g, 3.6 mmol) was added
1-bromobutane (2.49 g, 18.2 mmol), and the mixture was heated
under reflux for 4 days. After this time, solvent was removed in vacuo
and the residue was washed with 20 mL of ether to obtain pure
product (1.83 g, 3.3 mmol). Yield: 92%. 1H NMR (D2O-d2): δ 9.77 (s,
1H, benzimidazole-H), 8.88 (s, 1H, imidazole-H), 8.06 (t, JH−H = 7.9
Hz, 1H, py-H), 7.75 (m, 2H, benzimidazole-H), 7.69 (d, JH−H = 8.0
Hz, 1H), 7.55 (m, 4H), 7.45 (s, 1H, imi-H), 5.62 (s, 2H, NCH2-py),
4.46 (t, JH−H = 6.9 Hz, 2H, butyl-H), 4.04 (t, JH−H = 6.9 Hz, 2H, butyl-
H), 1.53 (m, 2H, butyl-H), 1.26 (m, 2H, butyl-H), 0.82 (m, 4H, butyl-
H), 0.46 (m, 6H, butyl-H) ppm. 13C NMR (D2O-d2): δ 164.93,
153.73, 141.99, 140.17, 136.69, 131.53, 129.98, 127.82, 127.51, 123.47,
123.40, 122.49, 117.15, 115.14, 113.60 (Ar-C); 52.62 (CH2); 49.46,
47.60, 31.08, 30.28, 19.06, 18.46, 16.70, 12.64 ppm (aliphatic C). Mass
(MALDI): m/z 468, 470 [M + Br]+; m/z 389 [M − 1]2+.
50.5 (CH2); 49.7, 47.1, 31.6, 31.1, 19.5, 19.2, 13.88, 13.80 ppm
(aliphatic C). Mass (MALDI): m/z 470, 472 [M + Br]+; 389 [M −
1]2+.
[Ru(L3)2](PF6)2. A mixture of L3H2·Br2 (0.08g, 0.15 mmol), sodium
acetate (0.25 g, 0.3 mmol), and RuCl3·H2O (0.015 g, 0.07 mmol) in
ethylene glycol (1 mL) was heated under reflux for 12 h. After cooling
to room temperature, water (5 mL) was added, and the aqueous phase
was extracted three times with dichloromethane (10 mL). The
combined organic phases were dried over MgSO4. After removal of the
solvent in vacuo, the crude product was dissolved in acetone (10 mL)
and precipitated with NH4PF6 (0.01 g, 0.017 mmol), by stirring the
mixture for 2 h. The yellow precipitate was filtered, dried, and further
purified by silica gel column chromatography using DCM/MeOH
(20:1) as eluent to afford a yellow solid (0.048 g, 0.04 mmol). Yield:
1
54%. H NMR (acetone-d6): δ 8.43 (m, 6H), 8.22 (d, JH−H = 1.2 Hz,
2H), 7.96 (d, JH−H = 1.2 Hz, 2H), 7.36 (m, 8H), 6.34 (d, JH−H = 15.1
Hz, 2H, py-CH-benzimidazole), 5.30 (d, JH−H = 15.1 Hz, 4H, py-CH-
benzimidazole), 3.35 (m, 4H, butyl-H), 2.27 (m, 2H, butyl-H), 1.26
(m, 2H, butyl-H), 0.68 (m, 14H, butyl-H), 0.48 (m, 8H, butyl-H), 0.11
(t, JH−H = 7.2 Hz, 6H) ppm. 13C NMR (acetonitrile-d3): δ 195.0,
193.2, 156.4, 155.6, 139.4, 134.7, 124.1, 123.0, 122.8, 121.4, 117.1,
111.5, 110.3, 109.3 (Ar-C); 50.5 (CH2); 48.7, 45.6, 32.3, 30.2, 19.8,
19.0, 12.7, 12.0 ppm (aliphatic-C). Mass (MALDI): m/z 1021 [M +
PF6]+. Anal. Calcd for C48H58F12N10P2Ru: C 49.44, N 12.01, H 5.01.
Found: C 49.35, N 11.93, H 5.06.
L4H2·Br2. To a dry DMF solution (20 mL) of 2-((benzimidazol-1-
yl)methyl)-6-(benzimidazol-1-yl)pyridine (0.6492 g, 1.9 mmol) in a
flame-dried Schlenk tube was added 1-bromobutane (0.82 g, 5.9
mmol), and the mixture was heated under reflux for 5 days. Then the
solvent was removed in vacuo, and the residue was washed with a
solvent mixture containing ether and methanol (5:1, v/v, 10 mL × 3)
1
to obtain pure product (0.7621 g, 1.27 mmol). Yield: 67%. H NMR
(MeOD-d4): δ 10.27 (s, 1H, benzimidazole-H), 10.02 (s, 1H,
benzimidazole-H), 8.28 (t, JH−H = 6.0 Hz, 1H, py-H), 8.00 (m, 3H),
7.67 (m, 3H), 7.54 (t, JH−H = 6.0 Hz, 1H), 7.45 (t, JH−H = 6.0 Hz, 1H),
6.19 (s, 2H, CH2), 4.57 (m, 4H, butyl-H), 1.99 (m, 2H, butyl-H), 1.84
(m, 2H, butyl-H), 1.43 (q, JH−H = 7.8 Hz, 2H, butyl-H), 1.20 (q, JH−H
= 7.6 Hz, 2H, butyl-H), 0.95 (t, JH−H = 7.4 Hz, 3H, butyl-H), 0.72 (t,
JH−H = 7.4 Hz, 3H, butyl-H) ppm. 13C NMR (MeOD-d4): δ 153.6,
147.5, 142.8, 141.9, 141.4, 131.8, 131.6, 129.8, 127.7, 127.3, 127.1,
123.7, 117.0, 115.2, 113.7, 113.6, 113.6 (Ar-C); 50.2 (CH2); 34.1, 30.8,
19.4, 19.2, 12.5, 12.4 ppm (aliphatic-C). Mass (MALDI): m/z 518, 520
[M + Br]+; 439 [M − 1]2+.
[Ru(L4)2](PF6)2. A mixture of L4H2·Br2 (0.29g, 0.49 mmol), sodium
acetate (0.08 g, 0.99 mmol), and RuCl3·H2O (0.05 g, 0.24 mmol) in
ethylene glycol (2 mL) was heated under reflux for 12 h. After cooling
to room temperature, water (5 mL) was added, and the aqueous phase
was extracted with dichloromethane (10 × 3 mL). The combined
organic phases were dried over MgSO4. After removal of the solvent
under reduced pressure, the crude product was dissolved in acetone
(10 mL) and subjected to counterion exchange using NH4PF6 (0.08 g,
5.0 mmol), by stirring the mixture for 2 h. The yellow precipitate was
filtrated, dried, and further subjected to silica gel column
chromatography using DCM/MeOH (20:1, v/v) as eluent, to afford
a yellow solid (0.14 g, 0.11 mmol). Yield: 45%. 1H NMR (acetone-d6):
δ 8.85 (d, JH−H = 6.0 Hz, 2H, py-H), 8.61 (t, JH−H = 6.1 Hz, 2H, py-
[Ru(L2)2](PF6)2. A mixture of L2H2·Br2 (0.4 g, 0.73 mmol), sodium
acetate (0.13 g, 1.53 mmol), and RuCl3·H2O (0.09 g, 0.44 mmol) in
ethylene glycol (3 mL) was heated under reflux for 12 h. After cooling
to room temperature, water (5 mL) was added, and the aqueous phase
was extracted with dichloromethane (10 mL × 3). The combined
organic phases were dried over MgSO4. After removal of the solvent
under reduced pressure, the crude product was dissolved in acetone
(10 mL) and precipitated with NH4PF6 (0.11 g, 0.67 mmol). The
mixture was stirred for 2 h to obtain a yellow precipitate, which was
filtered and further purified by column chromatography using silica gel
and DCM/MeOH (20:1) as the eluent, to obtain the product as a
1
yellow solid (0.24 g, 0.2 mmol). Yield: 55%. H NMR (acetonitrile-
d3): δ 8.43 (m, 6H), 8.21 (d, JH−H = 7.6 Hz, 2H), 7.96 (d, JH−H = 7.7
Hz, 2H), 7.37 (m, 8H), 5.48 (m, 2H, benzimidazole-CH-py), 5.02 (m,
2H, benzimidazole-CH-py), 3.40 (m, 2H, butyl-H), 2.71 (m, 2H,
butyl-H), 0.62 (m, 32H, butyl-H) ppm. 13C NMR (acetonitrile-d3): δ
180.32, 170.77, 156.50, 139.22, 135.54, 131.29, 124.87, 124.32, 122.72,
121.52, 121.21, 112.31, 112.08, 111.21 (Ar-C); 54.49 (CH2); 47.66,
46.17, 32.22, 30.91, 19.72, 19.60, 12.75, 12.39 ppm (aliphatic C). Mass
(MALDI): m/z 1021 [M + PF6]+. Anal. Calcd for C48H58F12N10P2Ru:
C 49.44, N 12.01, H 5.01. Found: C 49.61, N 12.12, H 5.13.
L3H2·Br2. To an acetonitrile solution (10 mL) of 2-((benzimidazol-
1-yl)methyl)-6-(imidazol-1-yl)pyridine (0.1 g, 0.36 mmol) was added
1-bromobutane (0.22 g, 1.61 mmol). The mixture was heated under
reflux for 3 days. After this time, solvent was removed in vacuo, and the
residue was washed with 10 mL of ether to obtain pure product (0.19
g, 0.35 mmol). Yield: 98%. 1H NMR (acetonitrile-d3): δ 10.98 (s, 1H,
imidazole-H), 10.79 (s, 1H, benzimidazole-H), 8.13 (t, JH−H = 7.9 Hz,
1H, py-H), 8.13 (s, 1H, imidazole-H), 7.93 (m, 4H, benzimidazole-H,
py-H), 7.65 (m, 2H, benzimidazole-H), 7.58 (s, 1H, imidazole-H),
H), 8.41 (d, JH−H = 6.9 Hz, 2H, benzimidazole-H), 8.36 (d, 2H, JH−H
=
7.2 Hz, py-H), 8.05 (d, JH−H = 8.1 Hz, 2H, benzimidazole-H), 7.46 (m,
10H, benzimidazole-H), 7.41 (m, 2H), 6.43 (d, JH−H = 15.2 Hz, 2H,
CH2), 5.40 (d, JH−H = 15.2 Hz, 2H, CH2), 3.80 (m, 2H, butyl-H), 3.50
(m, 2H, butyl-H), 2.93 (m, 2H, butyl-H), 2.36 (m, 2H, butyl-H), 1.19
(m, 4H, butyl-H), 0.75 (m, 4H, butyl-H), 0.48 (m, 4H, butyl-H), 0.11
(m, 16H, butyl-H) ppm. 13C NMR (acetone-d6): δ 204.8, 193.2, 156.8,
156.7, 140.5, 135.7, 134.8, 131.5, 125.2, 124.8, 123.3, 123.28, 121.8,
112.9, 112.7, 111.6, 110.7, 109.8 (Ar-C); 50.8 (CH2); 46.2, 45.8, 31.4,
30.8, 19.8, 19.7, 12.4, 12.3 ppm (aliphatic-C). Mass (MALDI): m/z
1121 [M + PF6]+; m/z 975 [M − 1]+. Anal. Calcd for
C56H62F12N10P2Ru: C 53.12, N 11.06, H 4.94. Found: C 52.98, N
10.91, H 5.04.
5.91 (s, 2H, CH2), 4.70 (t, JH−H = 7.2 Hz, 2H, butyl-H), 4.45 (t, JH−H
=
7.2 Hz, 2H, butyl-H), 1.95 (m, 4H, butyl-H), 1.39 (m, 4H, butyl-H),
0.96 (t, JH−H = 7.3 Hz, 3H, butyl-H), 0.93 (t, JH−H = 7.4 Hz, 3H, butyl-
H) ppm. 13C NMR (DMSO-d6): δ 153.3, 146.6, 143.8, 142.4, 135.6,
131.4, 127.3, 127.1, 124.4, 124.0, 119.5, 114.5, 114.4, 114.2 (Ar-C);
2580
dx.doi.org/10.1021/om500205p | Organometallics 2014, 33, 2575−2582