C. Lar et al.
+
m/z: 518.20, 520.20, 522.20; [M+K] m/z: 534.10,
36.10, 538.10. Anal. Calcd. for C H Br N O: C, 53.15;
5
22
15
2
3
H, 3.04; Br, 32.14; N, 8.45; found: C, 53.19; H, 3.13; Br,
32.05; N, 8.43.
6
,6”-dibromo-4’-[4”’-(methoxymethyl)phenyl]-
2,2’:6’,2”-terpyridine (3c)
2-acetyl-6-bromopyridine (1.60 g, 8.02 mmol) was
added to 120 mL MeOH solution of 4-(bromomethyl)
benzaldehyde (0.80 g, 4.01 mmol), NaOH (0.16 g,
4
.01 mmol) and 30 mL aq. NH OH 25%. The reaction
4
mixture was refluxed for 2 days and then let to reach
room temperature. The formed precipitate was filtered
Figure 1. 6,6”-symmetrically disubstituted 4’-aryl-terpyridines.
recorded on an Agilent 6320 ion trap mass spectrometer and washed with water and cold methanol and the crude
in positive mode. Elemental analyses were carried out product was purified by column chromatography on silica
on a Perkin-Elmer 2400-B microanalyser. The UV–Vis gel (CH Cl :Petroleum Ether=2:1, R = 0.7) to afford 3c.
2
2
f
absorption spectra (230–500 nm) were measured with a (Yield 1.12 g, 54%) Appearance: white solid, mp. 155ºC.
1
Perkin Elmer Lambda 35 UV-Vis spectrophotometer and
H NMR (300 MHz, CDCl ), δ ppm: 8.68 (s, 2H, H , H ),
3
3
’
5
’
3
4
the luminescence spectra (285–750 nm) were obtained 8.58 (dd, 2H, H , H , J = 7.8 Hz, J = 0.6 Hz), 7.86 (d,
withaPerkinElmerLS55Luminescenceat20 C.Relative 2H, H , H , J = 8.1 Hz), 7.71 (t, 2H, H , H , J = 7.8 Hz),
3
3”
o
3
3
2”’
6”’
4
4”
quantum yields were calculated using 2-aminopyridine 7.51 (overlapped signals, 4H, H , H , H , H ), 4.56 (s,
5
5”
3”’
5”’
13
in ethanol as standard (excitation at 285 nm, Φ = 0.37). 2H, -CH -O-), 3.43 (s, 3H, -O-CH ). C NMR (75 MHz,
2
3
All solvents used for spectrophotometric measurements CDCl ) δ ppm: 157.16, 154.32, 150.38, 141.57, 139.40,
3
were degassed prior to use. Melting points were 139.11, 137.34, 128.18, 128.15, 127.38, 119.95, 119.67,
+
measured with a Kleinfeld melting point apparatus and 74.17, 58.14. MS (MALDI+/DCTB): [M+H] m/z: 509.9,
+
+
are uncorrected. Thin layer chromatography (TLC) was 511.9, 513.9; [M+Na] m/z: 531.8, 533.8, 535.8; [M+K]
conducted on silica gel 60 F254 TLC plates purchased m/z: 547.8, 549.8, 551.8. Anal. Calcd. for C H Br N O:
23
17
2
3
from Merck. Preparative column chromatography was C, 54.04; H, 3.35; Br, 31.26; N, 8.22; found: C, 53.99; H,
performed using PharmPrep 60 CC (40–63 µm) silica 3.31; Br, 31.33; N, 8.25.
gel purchased from Merck. Chemicals and solvents
4’-(4”’-bromophenyl)-2,2’:6’,2”-terpyridine-6,6”-
were purchased from Merck or Acros and were used dicarboxylic acid (6b)
without further purification.
A solution of dinitrile 5 (0.70 g, 1.59 mmol) in acetic
Syntheses of 3a [12], 4 [12], 5 [12] and 6a [6] are acid (50 mL) and conc. HCl (20 mL) was refluxed for 16
described elsewhere.
h. The precipitate formed upon cooling was collected by
6
,6”-dibromo-4’-[4”’-(hydroxymethyl)phenyl]- filtration, washed with water and dried to afford diacid 6b
2
,2’:6’,2”-terpyridine (3b)
(Yield 0.69 g, 92%).Appearance: white solid, mp. 210ºC.
1
2-acetyl-6-bromopyridine (0.58 g, 2.92 mmol) was
H NMR (300 MHz, DMSO-d ) δ ppm: 8.89 (overlapped
6
added to 50 mL MeOH solution of 4-(hydroxymethyl) signals, 4H, H , H , H , H ), 8.22 (overlapped signals,
3’
5’
5
5”
3
benzaldehyde (0.20 g, 1.46 mmol), NaOH (0.05 g, 4H, H , H , H , H ), 7.94 (d, 2H, H , H , J = 8.7 Hz),
4
4”
3
3”
3”’
13
5”’
3
1
.46 mmol) and 10 mL aq. NH OH 25%. The reaction 7.83 (d, 2H, H , H , J = 8.7 Hz). C NMR (75 MHz,
4
2”’
6”’
mixture was refluxed for 2 days and then let to reach DMSO-d ) δ ppm: 165.14, 154.20, 154.04, 148.10,
6
room temperature. The precipitate formed was filtered, 147.16, 138.32, 135.91, 131.59, 128.62, 124.48, 123.61,
+
washed with water and cold methanol. The crude product 122.52, 118.25. MS (MALDI+/DCTB) [M+H] m/z:
+
+
was purified by column chromatography on silica gel 476.00, 478.00; [M+Na] m/z: 498.00, 500.00; [M+K]
(
(
AcOEt:Petroleum Ether=1:1, R = 0.4) to afford 3b. m/z: 514.00, 516.00. Anal. Calcd. for C H BrN O : C,
Yield 0.37 g, 52%) Appearance: white solid, mp. 251- 58.00; H, 2.96; Br, 16.78; N, 8.82; found: C, 58.08; H,
f
23 14 3 4
1
2
52°C. H NMR (300 MHz, CDCl ) δ ppm: 8.69 (s, 2H, 2.95; Br, 16.72; N, 8.80.
3
3
H , H ), 8.59 (d, 2H, H , H , J = 7.8 Hz), 7.88 (d, 2H,
H , H , J = 8.4 Hz), 7.72 (t, 2H, H , H J = 7.8 Hz), dicarboxylic acid dimethyl ester (6c)
4’-(4”’-bromophenyl)-2,2’:6’,2”-terpyridine-6,6”-
3’
5’
3
3”
3
3
2”’
6”’
4
4”
7
2
1
1
.54 (overlapped signals, 4H, H , H , H , H ), 4.81 (s,
Thionyl chloride (1.00 mL, 13.76 mmol) was added
H, -CH OH). C NMR (75 MHz, CDCl ) δ ppm: 156.45, dropwise to cold methanol (50 mL). After the mixture
53.68, 149.74, 142.56, 140.84, 138.55, 136.03, 127.50, was stirred for 15 min at room temperature, terpyridine
26.66, 126.52, 119.33, 118.83, 63.41. MS (MALDI+/ derivative 6b (1.00 g, 2.09 mmol) was added and
3”’
5”’
5
5”
13
2
3
+
+
DCTB): [M+H] m/z: 496.20, 498.20, 500.20; [M+Na]
the mixture refluxed for 5 h. After cooling, the white
2
19