Transition Met Chem
R
R
(0.5 mmol), N-heteroaryl halides (1.5 mmol), the selected
base (1.5 mmol) and solvent (4 mL). The flask was placed
in an oil bath and heated at 80 °C for 6 h, then cooled to
room temperature and extracted with CH2Cl2. The crude
products obtained from evaporation were purified by flash
chromatography on silica gel. The products 5b–c, 5f, 5m
[21], 5d [22], 5e [23], 5l [24] were known compounds and
characterized by the comparison of data with those in the
literature. The products 5a, 5g–k, 5n–o were new com-
pounds and characterized by elemental analysis, IR, MS,
1H and 13C NMR.
L
Cy2P
MeO
L
Pd Cl
Pd
L=
OMe
CH2Cl2
N
N
2
Cl
N
N
1 R=C2H5
2 R=OCH3
3 R=C2H5
4 R=OCH3
Scheme 1 Synthesis of complexes 3 and 4
DPX-400 spectrometer (400 and 100 MHz, respectively) in
CDCl3 with TMS as an internal standard. The absorption
and photoluminescence spectra were recorded on a Hitachi
U-3010 UV–Vis spectrophotometer and a Hitachi F-4500
fluorescence spectrophotometer, respectively, at room
temperature.
1,4-Bis(6-methylpyridin-2-yl)benzene 5a. Anal. Calcd.
for C18H16N2: C, 83.0; H, 6.2; N, 10.8. Found: C, 83.2; H,
6.1; N, 10.9 %. MS–ESI? [m/z]: 261.1 (M ? H)?. IR
(KBr, cm-1): 2917, 1575, 1558, 1449, 1417, 1263, 1163,
1090, 1030, 971, 808, 740. 1H NMR (400 MHz, CDCl3): d
8.12 (s, 4H), 7.67 (t, J = 6.2 Hz, 2H), 7.60 (d, J = 6.2 Hz,
2H), 7.13 (d, J = 6.0 Hz, 2H), 2.67 (s, 6H). 13C NMR
(100 MHz, CDCl3): 158.4, 156.5, 139.9, 136.9, 127.3,
121.8, 117.7, 29.7.
Synthesis of complexes 3 and 4
A solution of palladacyclic dimer 1 or 2 (0.1 mmol) and
Sphos (0.21 mmol) in CH2Cl2 (10 mL) was stirred at room
temperature for 30 min. The product was separated by
passing through a short silica gel column with CH2Cl2 as
eluent. The second band was collected to afford the cor-
responding complex 3 or 4 after the evaporation of the
solvent. Complex 3: Yellow solid, yield 85 %. Anal. Calcd.
for C38H46ClN2O2PPd: C, 62.0; H, 6.3; N, 3.8. Found: C,
62.2; H, 6.1; N, 4.0 %. MS–ESI? [m/z]: 699.2 (M–Cl)?. IR
(KBr, cm-1): 2922, 1587, 1516, 1470, 1365, 1248, 1157,
1105, 1053, 923, 822, 782. 1H NMR (400 MHz, CDCl3): d
8.96 (s, 1H), 8.66 (s, 1H), 7.98 (s, 1H), 7.97 (d, J = 6.4 Hz,
2H), 7.43–7.47 (m, 2H), 7.33–7.38 (m, 3H), 7.10–7.17 (m,
1H), 6.62 (d, J = 6.8 Hz, 2H), 3.69 (s, 6H), 2.75 (q, 2H),
1.62–1.87 (m, 12H), 1.13–1.38 (m, 13H). 13C NMR
(100 MHz, CDCl3): d 158.0, 139.1, 139.7, 132.4, 129.1,
129.0, 124.9, 119.2, 111.3, 103.4, 55.1, 33.2, 30.5, 28.8,
27.5, 26.9, 26.4. Complex 4: Yellow solid, yield 88 %.
Anal. Calcd. for C37H44ClN2O3PPd: C, 60.3; H, 6.0; N,
3.8. Found: C, 60.4; H, 5.9 N, 3.9 %. MS–ESI? [m/z]:
701.2 (M–Cl)?. IR (KBr, cm-1): 2924, 1608, 1584, 1516,
1,4-Bis(4-methylpyridin-2-yl)benzene 5g. Anal. Calcd.
for C18H16N2: C, 83.0; H, 6.2; N, 10.8. Found: C, 83.2; H,
6.1; N, 10.9 %. MS–ESI? [m/z]: 261.1 (M ? H)?. IR
(KBr, cm-1): 2923, 1609, 1567, 1464, 1420, 1389, 1334,
1
1272, 1146, 1120, 1084, 834, 739. H NMR (400 MHz,
CDCl3): d 8.59 (d, J = 4.0 Hz, 2H), 8.12 (s, 4H), 7.64 (s,
2H), 7.10 (d, J = 3.9, 2H), 2.45 (s, 6H). 13C NMR
(100 MHz, CDCl3): 156.8, 149.5, 147.9, 139.8, 127.2,
123.3, 121.6, 21.3.
1,4-Bis(6-methoxypyridin-2-yl)benzene 5h. Anal. Cal-
cd. for C18H16N2O2: C, 74.0; H, 5.5; N, 9.6; found: C, 74.1;
H, 5.4; N, 9.7 %. MS–ESI? [m/z]: 293.1 (M ? H)?. IR
(KBr, cm-1): 2924, 1600, 1577, 1467, 1420, 1393, 1326,
1
1284, 1254, 1162, 1083, 1024, 985, 874, 788. H NMR
(400 MHz, CDCl3): d 8.18 (s, 4H), 7.68 (t, J = 6.0 Hz,
2H), 7.43 (d, J = 6.0 Hz, 2H), 6.74 (d, J = 6.0 Hz, 2H),
4.10 (s, 6H). 13C NMR (100 MHz, CDCl3): 163.8, 154.2,
139.4, 139.2, 126.9, 112.9, 109.4, 53.3.
1,4-Bis(3-hydroxy-6-methylpyridin-2-yl)benzene
5i.
Anal. Calcd. for C18H16N2O2: C, 74.0; H, 5.5; N, 9.6.
Found: C, 74.1; H, 5.4; N, 9.7 %. MS–ESI? [m/z]: 293.1
(M ? H)?. IR (KBr, cm-1): 3236, 2922, 1447, 1377, 1269,
1236, 1211, 1143, 1029, 938, 823, 739. 1H NMR
(400 MHz, CDCl3): d 7.76 (d, J = 6.8 Hz, 2H), 7.48 (d,
J = 6.8 Hz, 2H), 7.19 (d, J = 4.0 Hz, 2H), 6.99 (d,
J = 4.0, 2H), 2.53 (s, 6H). 13C NMR (100 MHz, CDCl3):
149.7, 148.4, 145.0, 137.4, 128.8, 124.4, 123.1, 29.5.
1,4-Bis(5-trifluoromethylpyridin-2-yl)benzene 5j. Anal.
Calcd. for C18H10F6N2: C, 58.7; H, 2.7; N, 7.6. Found: C,
58.9; H, 2.6; N, 7.7 %. MS–ESI? [m/z]: 369.1 (M ? H)?. IR
(KBr, cm-1): 2921, 1601, 1558, 1465, 1421, 1255, 1107,
1
1469, 1396, 1249, 1179, 1107, 1034, 922, 825, 761. H
NMR (400 MHz, CDCl3): d 8.95 (s, 1H), 8.42 (s, 1H), 8.05
(m, 1H), 7.53 (d, J = 6.4 Hz, 1H), 7.44 (t, J = 6. 0 Hz,
1H), 7.37 (s, 1H), 7.16–7.25 (m, 3H), 6.50–6.63 (m, 4H),
3.50 (s, 6H), 3.34 (s, 3H), 1.58–1.73 (m, 22H). 13C NMR
(100 MHz, CDCl3): d 157.8, 143.1, 140.3, 133.5, 129.8,
129.6, 126.1, 123.2, 119.0, 103.7, 103.4, 64.9, 55.1, 29.7,
27.3, 27.2, 26.9.
General procedure for Suzuki coupling reactions
1
A 10-mL round-bottom flask was charged with the pre-
scribed amount of catalyst, 1,4-benzenediboronic acid
1025, 991, 859, 815, 790. H NMR (400 MHz, CDCl3): d
8.92 (d, J = 4.0 Hz, 2H), 8.21(s, 4H), 8.03 (s, 2H), 7.51 (d,
123