Synthesis of Phenylazomethine Dendrimer Ligands
J. Am. Chem. Soc., Vol. 123, No. 19, 2001 4419
(ethyl acetate:hexane ) 1:10, R
) 0.4). DPA G1: 1H NMR (400 MHz,
TEM result). The NMR studies revealed a conformational
rigidity of the DPA G4 molecules in the solution.
f
CDCl , 30 °C, TMS) δ 7.70 (d, J ) 7.6 Hz, 4H), 7.44 (t, J ) 7.6 Hz,
H), 7.37 (dd, J ) 7.6, 7.6 Hz, 4H), 7.28 (t, J ) 7.6 Hz, 2H), 7.23 (dd,
3
2
1
3
J ) 7.6, 7.6 Hz, 4H), 7.05 (d, J ) 7.6 Hz, 4H), 6.51 (s, 4H); C NMR
100 MHz, CDCl , 30 °C, TMS) δ 167.97, 146.83, 139.74, 136.28,
Experimental Section
(
3
-1
Synthesis of DPA Dendron G2. Benzophenone (25.7 g, 141 mmol),
130.47, 129.47, 129.14, 128.34, 128.06, 127.84, 121.33; IR (KBr, cm )
1618 (CdN), 1596 (phenyl), 840, 781, 697; EI-MS 436 [M] . Anal.
+
4
,4′-diaminobenzophenone (3.00 g, 14.1 mmol), and DABCO (9.51 g,
8
4.8 mmol) were dissolved in chlorobenzene (90 mL). Titanium(IV)
24 2
Calcd for C33H N : C, 88.04; H, 5.54; N, 6.42. Found: C, 88.19, H,
tetrachloride (4.02 g, 21.2 mmol) was added dropwise. The addition
funnel was rinsed with chlorobenzene (2 mL). The reaction mixture
was heated in an oil bath at 125 °C for 24 h. The precipitate was
removed by filtration. The filtrate was concentrated; the dendron G2
5.35; N, 6.40.
Synthesis of DPA G2. The dendron G2 (1.00 g, 1.85 mmol),
p-phenylenediamine (100 mg, 0.925 mmol), and DABCO (623 mg,
5.55 mmol) were dissolved in chlorobenzene (30 mL). Titanium(IV)
tetrachloride (264 mg, 1.39 mmol) was added dropwise. The additional
funnel was rinsed with chlorobenzene (2 mL). The reaction mixture
was heated in an oil bath at 125 °C for 24 h. The precipitate was
removed by filtration. The filtrate was concentrated; DPA G2 (664 mg,
0.576 mmol, 62%) was isolated by silica gel column chromatography
(ethyl acetate:hexane ) 1:6-1:4, including 1% Et N, R ) 0.4 in the
(
3.63 g, 6.71 mmol, 48%) was isolated by silica gel column chroma-
tography (ethyl acetate:hexane ) 1:7-1:4, including 1% Et N, R
.32 in the solution of ethyl acetate:hexane ) 1:5). DPA dendron G2:
3
f
)
0
1
H NMR (400 MHz, CDCl
3
, 30 °C, TMS) δ 7.76 (br, 4H), 7.57 (d, J
)
8.4 Hz, 4H), 7.46 (br, 2H), 7.40 (br, 4H), 7.26 (br, 6H), 7.12 (br,
H), 6.76 (d, J ) 8.4 Hz, 4H); C NMR (100 MHz, CDCl , 30 °C,
3
1
3
4
3
f
solution of ethyl acetate:hexane ) 1:4). DPA G2: 1H NMR (400 MHz,
TMS) δ 195.02, 168.67, 155.11, 139.00, 135.62, 132.53, 131.03, 130.92,
1
29.40, 129.27, 128.88, 128.20, 127.99, 120.27; IR (KBr, cm-1) 1647
CDCl , 30 °C, TMS) δ 7.76 (d, J ) 7.3 Hz, 4H), 7.71 (d, J ) 7.3 Hz,
3
+
(CdO), 1618 (CdN), 1581 (phenyl), 848, 781, 697; EI-MS 540 [M] .
4H), 7.49 (d, J ) 8.4 Hz, 4H), 7.46-7.35 (m, 12H), 7.28 (m, 6H),
7.19-7.13 (m, 10H), 7.01 (m, 4H), 6.73 (d, J ) 8.4 Hz, 4H), 6.71 (d,
Anal. Calcd for C39
6.87, H, 4.92; N, 5.09.
Synthesis of DPA Dendron G3. The dendron G2 (4.85 g, 8.97
mmol), 4,4′-diaminobenzophenone (380 mg, 1.79 mmol), and DABCO
1.21 g, 10.8 mmol) were dissolved in chlorobenzene (40 mL).
28 2
H N O: C, 86.64; H, 5.22; N, 5.18. Found: C,
1
3
8
J ) 8.4 Hz, 4H), 6.54 (d, J ) 8.4 Hz, 4H), 6.37 (s, 4H); C NMR
(100 MHz, CDCl , 30 °C, TMS) δ 168.74, 168.44, 167.34, 153.42,
151.69, 146.96, 139.45, 139.32, 136.00, 135.80, 135.11, 131.03, 130.85,
130.47, 129.88, 129.49, 129.42, 128.80, 128.19, 128.06, 127.94, 121.71,
120.54, 120.10; IR (KBr, cm ) 1617 (CdN), 1584 (phenyl), 844, 784,
3
(
-
1
Titanium(IV) tetrachloride (510 mg, 2.69 mmol) was added dropwise.
The addition funnel was rinsed with chlorobenzene (2 mL). The reaction
mixture was heated in an oil bath at 125 °C for 24 h. The precipitate
was removed by filtration. The filtrate was concentrated; the dendron
G3 (1.43 g, 1.14 mmol, 64%) was isolated by silica gel column
+
697; FAB-MS 1153 [M + 1] . Anal. Calcd for C84
H, 5.24; N, 7.29. Found: C, 87.61, H, 5.16; N, 7.13.
60 6
H N : C, 87.47;
Synthesis of DPA G3. The dendron G3 (600 mg, 0.477 mmol),
p-phenylenediamine (21.6 mg, 0.200 mmol), and DABCO (135 mg,
1.20 mmol) were dissolved in chlorobenzene (30 mL). Titanium(IV)
tetrachloride (56.9 mg, 0.300 mmol) was added dropwise. The addition
funnel was rinsed with chlorobenzene (2 mL). The reaction mixture
was heated in an oil bath at 125 °C for 24 h. The precipitate was
removed by filtration. The filtrate was concentrated; DPA G3 (230 mg,
0.0890 mmol, 45%) was isolated by silica gel column chromatography
(ethyl acetate:hexane ) 1:5-1:2, including 1% Et N, R ) 0.46 in the
chromatography (ethyl acetate:hexane ) 1:5-1:3, including 1% Et
f
3
N,
R
) 0.24 in solution of ethyl acetate:hexane ) 1:4). DPA dendron
1
G3: H NMR (400 MHz, CDCl
3
, 30 °C, TMS) δ 7.77-7.66 (m, 8H),
7
1
4
7
1
1
1
.58 (d, J ) 8.4 Hz, 4H), 7.53 (d, J ) 8.0 Hz, 4H), 7.49-7.32 (m,
2H), 7.29 (br, 6H), 7.14 (br, 10H), 6.98 (br, 4H), 6.86 (d, J ) 7.6 Hz,
H), 6.74 (d, J ) 8.0 Hz, 4H), 6.69 (d, J ) 8.4 Hz, 4H), 6.56 (d, J )
.6 Hz, 4H); C NMR (100 MHz, CDCl , 30 °C, TMS) δ 194.89,
69.00, 168.48, 155.57, 153.98, 152.06, 139.25, 139.07, 135.85, 135.60,
33.97, 132.22, 130.95, 130.16, 130.05, 129.37, 128.80, 128.17, 128.02,
27.84, 120.68, 120.53, 120.28; IR (KBr, cm ) 1647 (CdO), 1617
1
3
3
3
f
solution of ethyl acetate:hexane ) 1:2). DPA G3: 1H NMR (400 MHz,
CDCl , 30 °C, TMS) δ 7.76-7.63 (m, 16H), 7.50-7.33 (m, 36H),
3
-
1
7.31-7.22 (m, 16H), 7.19-7.11 (m, 12H), 7.06 (br, 4H), 6.95 (br, 8H),
6.84 (d, J ) 8.4 Hz, 4H), 6.76-6.71 (m, 12H), 6.67 (d, J ) 8.4 Hz,
4H), 6.59 (d, J ) 8.4 Hz, 4H), 6.54 (d, J ) 8.4 Hz, 4H), 6.51 (d, J )
8.4 Hz, 4H), 6.44 (d, J ) 8.4 Hz, 4H), 6.43 (s, 4H); 13C NMR (100
+
(
CdN), 1581 (phenyl), 848, 781, 697; FAB-MS 1257 [M + 1] . Anal.
Calcd for C91
64 6
H N O: C, 86.91; H, 5.13; N, 6.68. Found: C, 86.59,
H, 4.79; N, 6.51.
Synthesis of DPA Dendron G4. Dendron G3 (9.52 g, 7.57 mmol),
,4′-diaminobenzophenone (268 mg, 1.26 mmol), and DABCO (849
3
MHz, CDCl , 30 °C, TMS) δ 169.00, 168.83, 168.51, 168.41, 168.11,
4
167.17, 153.83, 153.78, 153.68, 152.12, 151.95, 151.87, 147.10, 139.41,
139.26, 139.08, 135.94, 135.81, 135.63, 134.56, 134.48, 134.43, 130.88,
130.78, 130.73, 130.47, 130.30, 130.16, 130.11, 129.98, 129.45, 129.30,
128.86, 128.71, 128.23, 128.08, 127.95, 127.90, 121.86, 120.82, 120.79,
120.51, 120.33, 120.00; IR (KBr, cm ) 1617 (CdN), 1581 (phenyl),
847, 783, 696; MALDI-TOF-MS calcd 2587.2 [M] , found 2587.0.
mg, 7.57 mmol) were dissolved in chlorobenzene (120 mL). Titanium-
IV) tetrachloride (358 mg, 1.89 mmol) was added dropwise. The
(
addition funnel was rinsed with chlorobenzene (2 mL). The reaction
mixture was heated in an oil bath at 125 °C for 44 h. The precipitate
was removed by filtration. The filtrate was concentrated; the dendron
G4 (668 mg, 0.248 mmol, 20%) was isolated by silica gel column
chromatography (ethyl acetate:hexane:dichloromethane ) 1:6:6-1:3:
-
1
+
Anal. Calcd for C188
87.43, H, 4.84; N, 7.37.
132
H N14: C, 87.28; H, 5.14; N, 7.58. Found: C,
3
, R
f
) 0.377 in the solution of ethyl acetate:hexane:dichloromethane
Synthesis of DPA G4. The dendron G4 (400 mg, 0.149 mmol),
p-phenylenediamine (8.0 mg, 0.074 mmol), and DABCO (49.8 mg,
0.444 mmol) were dissolved in chlorobenzene (20 mL). Titanium(IV)
tetrachloride (21.1 mg, 0.111 mmol) was added dropwise. The addition
funnel was rinsed with chlorobenzene (2 mL). The reaction mixture
was heated in an oil bath at 125 °C for 24 h. The precipitate was
removed by filtration. The filtrate was concentrated; DPA G4 (125 mg,
0.0229 mmol, 31%) was isolated by silica gel column chromatography
f
1
)
1:5:5). DPA dendron G4: H NMR (400 MHz, CDCl
3
, 30 °C, TMS)
, 30 °C, TMS) δ
94.68, 168.87, 168.43, 168.23, 168.12, 155.46, 154.39, 153.78, 152.07,
1
3
δ 7.74-6.35 (m, 136H); C NMR (100 MHz, CDCl
3
1
1
1
1
1
39.28, 139.05, 135.83, 134.24, 133.66, 132.36, 130.90, 130.60, 130.21,
30.08, 129.98, 129.36, 128.80, 128.17, 128.01, 127.83, 120.89, 120.74,
20.50, 120.28, 120.04; IR (KBr, cm- ) 1647 (CdO), 1617 (CdN),
1
578 (phenyl), 848, 784, 695; MALDI-TOF-MS calcd 2690.11 [M +
+
H] , found 2690.36. Anal. Calcd for C195
H
136
N14O: C, 87.03; H, 5.09;
(ethyl acetate:hexane:dichloromethane ) 1:4:4-1:3:3, R ) 0.45 in
N, 7.29. Found: C, 87.11, H, 5.24; N, 6.89.
solution of ethyl acetate:hexane:dichloromethane ) 1:3:3). DPA G4:
1
Synthesis of DPA G1. Benzophenone (1.69 g, 9.25 mmol),
p-phenylenediamine (500 mg, 4.62 mmol), and DABCO (3.11 g, 27.7
mmol) were dissolved in chlorobenzene (40 mL). Titanium(IV)
tetrachloride (1.32 g, 6.93 mmol) was added dropwise. The addition
funnel was rinsed with chlorobenzene (2 mL). The reaction mixture
was heated in an oil bath at 125 °C for 24 h. The precipitate was
removed by filtration. The filtrate was concentrated; DPA G1 (1.83 g,
H NMR (400 MHz, CDCl
C NMR (100 MHz, CDCl
3
, 30 °C, TMS) δ 7.80-6.31 (m, 276H);
, 30 °C, TMS) δ 169.02, 168.79, 168.47,
13
3
168.14, 167.95, 167.78, 166.89, 154.19, 154.04, 153.78, 152.27, 151.97,
151.72, 139.39, 139.18, 139.00, 135.89, 135.70, 134.48, 134.33, 134.17,
130.93, 130.70, 130.35, 130.14, 129.43, 128.86, 128.66, 128.22, 128.07,
127.92, 121.67, 121.05, 120.87, 120.79, 120.52, 120.33, 120.05; IR
-1
(KBr, cm ) 1617 (CdN), 1578 (phenyl), 848, 784, 696; MALDI-TOF-
+
4
.19 mmol, 91%) was isolated by silica gel column chromatography
MS calcd 5451.26 [M + H] , found 5451.48.