3604 Chow et al.
Macromolecules, Vol. 37, No. 10, 2004
Tr is(tr im eth ylsilyleth yn yl) G1 Den d r im er 23. A mix-
ture of the triiodo G1 dendrimer 21 (0.40 g, 0.17 mmol),
trimethylsilylacetylene (0.30 mL, 2.1 mmol), CuI (2 mg, 0.01
mmol), PPh3 (2 mg, 0.008 mmol), Pd(PPh3)2Cl2 (20 mg, 0.028
mmol), and NEt3 (0.3 mL) in toluene (4 mL) was stirred in a
sealed tube at 60 °C for 6 h. The mixture was filtered and then
washed with Et2O (20 mL). The filtrate obtained was concen-
trated under reduced pressure. The residue was purified by
column chromatography (eluent: hexane gradient to hexane/
EtOAc ) 10/1) to give compound 23 (0.30 g, 78%) as a yellow
oil. Rf: 0.44 (hexane/EtOAc ) 5/1). 1H NMR: 0.23 (s, 27 H,
Si(CH3)3), 1.25-1.50 (m, 36 H), 1.29 (s, 27 H, C(CH3)3) 1.75-
1.80 (m, 12 H), 2.05-2.10 (m, 9 H, Ar3CCH3 and ArCH2CH2-
CH2O), 2.21 (quin, J ) 6.0, 6 H, OCH2CH2CH2O), 2.72 (t, J )
6.4, 6 H, ArCH2), 3.85-4.00 (m, 18 H, ArOCH2), 4.11 (t, J )
5.4, 6 H, ArOCH2), 4.12 (t, J ) 5.4, 6 H, ArOCH2), 6.30 (t, J )
2.1, 3 H, ArH), 6.36 (d, J ) 1.8, 6 H, ArH), 6.72-6.87 (m, 18
H, ArH), 6.97 (d, J ) 9.0, 6 H, ArH), 7.28 (d, J ) 8.7, 6 H,
ArH), 7.38 (d, J ) 8.7, 6 H, ArH). 13C NMR: 0.1 (Si(CH3)3),
26.0, 29.2, 29.4, 29.5, 30.7, 31.5 (C(CH3)3), 32.5, 34.0, 50.6
(Ar3CMe), 64.35, 64.42, 66.9, 67.9, 68.0, 92.2 (CtCSi), 98.8,
105.3 (ArCtC), 106.9, 107.2, 113.6, 113.9, 114.3, 126.2, 129.6,
133.4, 141.7, 143.4, 143.9, 156.6, 157.0, 159.3, 160.0, 160.3.
SEC: Rt 29.06 min. MS (MALDI-TOF): m/z 2337.1 [(M +
Na)+, 100%]. Anal. Calcd for C149H198O15Si3: C, 77.36; H, 8.63.
Found: C, 77.37; H, 8.62.
Tr is(tr im eth ylsilyleth yn yl) G2 Den d r im er 24. A mix-
ture of the triiodo G2 dendrimer 22 (0.23 g, 0.052 mmol),
trimethylsilylacetylene (0.10 mL, 0.71 mmol), CuI (2 mg, 0.01
mmol), PPh3 (2 mg, 0.008 mmol), Pd(PPh3)2Cl2 (10 mg, 0.014
mmol), and NEt3 (0.10 mL) in toluene (1 mL) was stirred in a
sealed tube at 60 °C for 6 h. The mixture was filtered and
washed with Et2O (20 mL). The filtrate was concentrated
under reduced pressure and the residue was purified by
column chromatography (eluent: hexane gradient to hexane/
EtOAc ) 5/1) to afford compound 24 (0.15 g, 67%) as a yellow
oil. Rf: 0.71 (hexane/EtOAc ) 3/1). 1H NMR: 0.23 (s, 27 H,
Si(CH3)3), 1.25-1.50 (m, 36 H), 1.28 (s, 81 H, C(CH3)3), 1.65-
1.80 (m, 12 H), 2.05-2.10 (m, 21 H, Ar3CCH3 and ArCH2CH2-
CH2O), 2.20 (quin, J ) 5.7, 18 H, OCH2CH2CH2O), 2.70 (t, J
) 7.2, 18 H, ArCH2), 3.84-4.00 (m, 30 H, ArOCH2), 4.08 (t, J
) 7.5, 18 H, ArOCH2), 4.10 (t, J ) 7.5, 18 H, ArOCH2), 6.27-
6.37 (m, 27 H, ArH), 6.73-6.86 (m, 30 H, ArH), 6.97 (d, J )
9.0, 6 H, ArH), 7.28 (d, J ) 8.7, 18 H, ArH), 7.38 (d, J ) 8.7,
6 H, ArH). 13C NMR (signals of CtC and the quaternary
carbon of the central core were too weak to be detected): 0.1
(Si(CH3)3), 26.0, 29.2, 29.4, 29.5, 30.7, 31.5 (C(CH3)3), 32.5, 34.0,
64.35, 64.43, 66.9, 68.0, 98.8, 107.1, 107.2, 113.6, 113.9, 114.3,
126.2, 129.6, 133.4, 143.3, 143.8, 156.6, 160.0, 160.2. SEC: Rt
27.83 min. MS (MALDI-TOF): m/z 4378.3 [(M + Na)+, 8%].
Anal. Calcd (%) for C281H366O33Si3: C, 77.48; H, 8.47. Found:
C, 77.05; H, 8.27.
The reaction was then quenched with water and extracted with
EtOAc (40 mL × 2). The combined organic layers were washed
with brine (40 mL), dried (MgSO4), and concentrated under
reduced pressure. The residue was purified by column chro-
matography (eluent: hexane/EtOAc ) 8/1 gradient to 5/1) to
afford compound 13 (0.20 g, 74%) as a colorless oil. Rf: 0.37
(hexane/EtOAc ) 5/1). 1H NMR: 1.25-1.50 (m, 36 H), 1.29 (s,
27 H, C(CH3)3), 1.75-1.80 (m, 12 H), 2.05-2.10 (m, 9 H, Ar3-
CCH3 and ArCH2CH2CH2O), 2.21 (quin, J ) 6.0, 6 H, OCH2CH2-
CH2O), 2.72 (t, J ) 6.4, 6 H, ArCH2), 2.98 (s, 3 H, CtCH),
3.85-4.00 (m, 18 H, ArOCH2), 4.10 (t, J ) 5.4, 6 H, ArOCH2),
4.11 (t, J ) 5.4, 6 H, ArOCH2), 6.30 (t, J ) 2.1, 3 H, ArH),
6.35 (d, J ) 1.8, 6 H, ArH), 6.74-6.88 (m, 18 H, ArH), 6.97 (d,
J ) 9.0, 6 H, ArH), 7.28 (d, J ) 8.7, 6 H, ArH), 7.40 (d, J )
8.7, 6 H, ArH). 13C NMR: 25.97, 26.04, 29.1, 29.28, 29.35, 29.5,
30.7, 30.8, 31.5 (C(CH3)3), 32.5, 34.0, 50.6 (Ar3CMe), 64.35,
64.42, 66.9, 67.9, 68.0, 75.6 (CtCH), 83.8 (ArCtC), 98.8, 106.9,
107.2, 113.6, 113.8, 113.9, 114.4, 126.2, 129.6, 133.5, 141.7,
143.4, 143.9, 156.6, 157.0, 159.5, 160.0, 160.3. SEC: Rt 29.26
min. MS (MALDI-TOF): m/z 2118.4 [(M + Na)+, 12%]. Anal.
Calcd for C140H174O15: C, 80.19; H, 8.36. Found: C, 80.32; H,
8.47.
Tr is(eth yn yl) G2 Den d r im er 14. Powdered K2CO3 (50 mg,
0.36 mmol) was added into a solution of the tris(trimethylsi-
lylethynyl) G2 dendrimer 24 (0.15 g, 0.034 mmol) in MeOH/
THF (1:1, 2 mL). The mixture was stirred at 25 °C for 1.5 h.
The reaction was then quenched with water and extracted with
EtOAc (30 mL × 2). The combined organic layers were washed
with brine (30 mL), dried (MgSO4), and concentrated under
reduced pressure. The residue was purified by column chro-
matography (eluent: hexane/EtOAc ) 6/1) to give compound
14 (0.12 g, 84%) as a colorless oil. Rf: 0.43 (hexane/EtOAc )
1
3/1). H NMR: 1.25-1.50 (m, 36 H), 1.28 (s, 81 H, C(CH3)3),
1.65-1.80 (m, 12 H), 2.05-2.10 (m, 21 H, Ar3CCH3 and
ArCH2CH2CH2O), 2.20 (quin, J ) 6.0, 18 H, OCH2CH2CH2O),
2.70 (t, J ) 7.5, 18 H, ArCH2), 2.98 (s, 3 H, CtCH), 3.84-4.00
(m, 30 H, ArOCH2), 4.08 (t, J ) 7.5, 18 H, ArOCH2), 4.10 (t, J
) 7.5, 18 H, ArOCH2), 6.30-6.40 (m, 27 H, ArH), 6.74-6.87
(m, 30 H, ArH), 6.97 (d, J ) 8.7, 6 H, ArH), 7.28 (d, J ) 8.7,
18 H, ArH), 7.40 (d, J ) 8.7, 6 H, ArH). 13C NMR (signal of
the quaternary carbon of the central core was too weak to be
detected): 26.0, 29.1, 29.4, 29.5, 30.7, 31.5 (C(CH3)3), 32.5, 34.0,
64.35, 64.44, 66.9, 67.9, 68.0, 75.6 (CtCH), 83.8 (ArCtC), 98.9,
107.1, 107.2, 113.6, 113.9, 114.4, 126.2, 129.6, 133.5, 141.7,
143.3, 143.9, 156.6, 157.0, 159.5, 160.0, 160.2. SEC: Rt 28.28
min. Anal. Calcd for C272H342O33: C, 78.92; H, 8.33. Found:
C, 78.78; H, 8.24.
4.3.3. Dip la tin u m Com p lex 5. A mixture of 1,1′-bis-
(ethynyl)-4,4′-biphenyl (0.35 g, 1.7 mmol), trans-[Pt(PEt3)2Cl2]
(1.90 g, 3.78 mmol) and CuCl (40 mg, 0.40 mmol) in i-Pr2NH/
PhMe (1:1, 20 mL) was heated at 100 °C for 6 h. The excess
solvent was then evaporated under reduced pressure and the
residue purified by column chromatography (eluent: hexane/
EtOAc ) 4/1) to give the diplatinum complex 5 (1.00 g, 51%)
as a yellow solid. Rf: 0.42 (hexane/EtOAc ) 3/1). Mp > 230
°C dec. 1H NMR: 1.21 (dt, J ) 16.2 and 7.8, 36 H, PCH2CH3),
2.00-2.20 (m, 24 H, PCH2CH3), 7.29 (d, J ) 8.1, 4 H, ArH),
7.43 (d, J ) 8.1, 4 H, ArH). 13C NMR: 8.0 (pseudo t, J ) 9.7,
PCH2CH3), 14.5 (pseudo quin, J ) 17.1, PCH2CH3), 83.4 (t, J
) 14.8), 101.5, 126.3, 127.5, 131.2, 137.7. 31P{1H} NMR: 17.51
(1J Pt-P ) 2393). MS (FAB): m/z 1133 (M+, 52%). Anal. Calcd
for C40H68Cl2P4Pt2: C, 42.37; H, 6.04. Found: C, 42.32; H, 6.19.
Tr is(eth yn yl) G0 Den d r im er 12. Powdered K2CO3 (0.33
g, 2.4 mmol) was added into a solution of the tris(trimethyl-
silylethynyl) G0 dendrimer 18 (0.50 g, 0.39 mmol) in MeOH/
THF (1:1, 4 mL). The mixture was stirred at 25 °C for 1.5 h.
The reaction was then quenched with water and extracted with
EtOAc (50 mL × 2). The combined organic layers were washed
with brine (50 mL), dried (MgSO4), and concentrated under
reduced pressure. The residue was purified by column chro-
matography (eluent: hexane/EtOAc ) 8/1) to afford compound
12 (0.23 g, 55%) as a colorless oil. Rf: 0.51 (hexane/EtOAc )
5/1). 1H NMR: 1.20-1.50 (m, 36 H), 1.70-1.85 (m, 12 H), 2.10
(s, 3 H, Ar3CCH3), 2.99 (s, 3 H, CtCH), 3.92 (t, J ) 6.6, 6 H,
ArOCH2), 3.94 (t, J ) 6.6, 6 H, ArOCH2), 6.78 (d, J ) 7.8, 6 H,
ArH), 6.82 (d, J ) 7.8, 6 H, ArH), 6.98 (d, J ) 8.7, 6 H, ArH),
7.41 (d, J ) 8.7, 6 H, ArH). 13C NMR: 26.0, 26.1, 29.1, 29.3,
29.5, 30.8, 50.5 (Ar3CMe), 67.8, 68.0, 75.6 (CtCH), 83.8 (ArCt
C), 113.5, 113.8, 114.4, 129.6, 133.5, 141.7, 157.1, 159.5. SEC:
Rt 31.27 min. MS (FAB): m/z 1076 (M+, 14%). Anal. Calcd for
4.3.4. Syn th esis of Typ e I G1-G3 Den d r itic Netw or k s
9-11. Typ e I G1 Den d r itic Netw or k 9. A catalytic amount
of CuI (5 mg, 0.03 mmol) was added to a mixture of the bis-
(ethynyl) G1 dendrimer 6 (0.123 g, 0.094 mmol), triplatinum
complex 3 (0.10 g, 0.063 mmol) in CH2Cl2/i-Pr2NH (1:1, 10 mL).
After the reaction was stirred at 25 °C for 6 h, the excess
solvent was evaporated under reduced pressure, and the
resulting gel was washed with CH2Cl2 (10 mL). The resulting
gel was broken up into small pieces and washed with CH2Cl2
to remove the soluble fractions. The sample was then freeze-
dried to give the type I G1 dendritic network 9 (0.18 g, 83%)
as a yellowish green solid.
C
74H90O6: C, 82.64; H, 8.43. Found: C, 82.59; H, 8.57.
Tr is(eth yn yl) G1 Den d r im er 13. Powdered K2CO3 (0.20
g, 1.5 mmol) was added into a solution of the tris(trimethyl-
silylethynyl) G1 dendrimer 23 (0.30 g, 0.13 mmol) in MeOH/
THF (1:1, 3 mL). The mixture was stirred at 25 °C for 1.5 h.