9922 Shifrina et al.
Macromolecules, Vol. 38, No. 24, 2005
+
cedure. 1H NMR spectrum (400 MHz, CDCl3): 8.69, 8.66
(2d, 2H, PyH), 8.50, 8.43 (2d, 2H, PyH), 7.85-7.69 (m,
4H, PyH), 7.66-6.93 (m, 8H, PyH). FD-MS: m/z (u e-1):
388 (M+). Elem anal. calcd for C25H16N4O, %: C, 77.31;
H, 4.15; N, 14.42; found: C, 77.51; H, 4.23; N, 14.06.
7820 (M
Na, calcd 7795.96). Elem anal. calcd for
C
537H556N24Si16, %: C 82.74, H 7.19, N 4.31, Si 5.76;
found: C 81.79, H 6.92, N 4.22, Si 5.48.
Synthesis of Td-G2-(Ethynyl)16. A solution of Td-
G2-(EthynylTiPS)16 in THF and benzene was treated
according to the general procedure (see above) for the
desilylation of triisopropylsilyl derivatives. Yield: 68.3%.
1H NMR spectrum (400 MHz, CDCl3): 8.62 (d, 12H,
PyH), 8.28 (d, 12H, PyH), 7.78, 7.77, 7.72 (3s, 12H, ArH),
7.47-6.52 (m, 184H, ArH), 3.05, 3.02 (2s, 16H, acety-
lene). MALDI-TOF m/e: 5293 (M+, calcd 5294.42). Elem
anal. calcd for C393H236N24, %: C 89.16, H 4.49, N 6.35;
found: C 88.06, H 4.31, N 6.22.
Synthesis of Td-G3-Ph (7). This compound was
prepared according to the general procedure (see above)
for the Diels-Alder reaction between tetraarylcyclo-
pentadienones and aryl-ethynyl derivatives by using
Td-G2-(Ethynyl)16 and 2,3,4,5-tetraphenylcyclopenta-
dienone. Yield: 74%. 1H NMR spectrum (400 MHz,
CDCl3): 8.54 (d, 12H, PyH), 8.18 (d, 12H, PyH), 7.73-
7.62 (m, 28H, ArH), 7.50-6.39 (m, 504H, ArH). MALDI-
TOF m/e: 10995 (M+, calcd 10997.97). Elem anal. calcd
for C841H556N24, %: C 91.85, H 5.10, N 3.06; found: C
90.68, H 4.88, N 2,91.
Synthesis of Td-G3-Py (8). This compound was
prepared according to the general procedure (see above)
for the Diels-Alder reaction between tetraarylcyclo-
pentadienones and aryl-ethynyl derivatives by using
Td-G2-(Ethynyl)16 and 2,3,4,5-tetrapyridylcyclopenta-
dienone (2). Yield: 71%. MALDI-TOF m/e: 11061.60
(M+, calcd 11061.17). Elem anal. calcd for C777H492N88,
%: C 84.37, H 4.48, N 11.14; found: C 83.27, H 4.31, N
10.96.
General Procedure for the Diels-Alder Reac-
tion Between Tetraarylcyclopentadienones and
Aryl-ethynyl Derivatives. The reaction was carried
out in a Schlenk flask under argon. The reaction flask
with the cyclopentadienone (Cp, 1.5-2 mol of Cp per 1
ethynyl group) solution in o-xylene (or diphenyl ether
for high generations) (4.5 × 10-3 mol/L) was evacuated
and filled with argon three times and then heated to
100 °C. A solution of aryl-ethynyl derivative in o-xylene
was slowly added, the temperature was increased up
to reflux. The reaction was controlled by TLC, and the
reaction time was dependent on the generation and
varied from 5 h for G1 and G2 to 45 h for G4. After
cooling, the solvent was evaporated, a small amount of
CH2Cl2 was added, and the compound was precipitated
in methanol.
General Procedure for the Desilylation of Tri-
isopropylsilyl (TiPS) Substituted Dendrimers. Tri-
isopropylsilyl-substituted dendrimer (0.06 mmol) was
dissolved in a mixture of THF (20 mL) and benzene (6
mL). To this solution, tetrabutylammonium fluoride
trihydrate (3 mol Bu4NF per 1 triisopropylsilyl group)
in THF (6 mL) was added. After 8 h stirring, CH2Cl2 (5
mL) was added, and the organic phase was washed with
water and dried over MgSO4. After evaporating the
solvent, the crude product was purified by reprecipita-
tion in methanol.
Synthesis of Td-G1-(EthynylTiPS)8. This com-
pound was prepared according to a general proce-
dure (see above) for the Diels-Alder reaction between
tetraarylcyclopentadienones and aryl-ethynyl deriva-
tives by using tetra(4-ethynylphen-1-yl)methane (Td)
(0.416 g, 1 mmol) and 3,4-bis-(4-(triisopropylsilylethyn-
yl)phen-1-yl)-2,5-dipyrid-2-yl-cyclopentan-2,4-dienone (1)
(4.4831 g, 6 mmol). Yield: 91% (1.35 g). 1H NMR
spectrum (400 MHz, CDCl3): 8.58 (d, 4H, PyH), 8.25
(d, 4H, PyH), 7.78 (s, 4H, ArH), 7.49-6.52 (m, 72H,
ArH), 1.09(s, 42H, aliph). MALDI-TOF m/e: 3293 (M+,
calcd 3293.26). Elem anal. calcd for C225H252N8Si8, %:
C 82.0, H 7.71, N 3.40, Si 6.82; found: C 80.99, H 7.39,
N 3.10, Si 6.51.
Synthesis of Td-G1-(Ethynyl)8 (5). A solution of
1.35 g (0.41 mmol) of Td-G1-(EthynylTiPS)8 in THF
(170 mL) and benzene (50 mL) was treated according
to the general procedure (see above) for desilylation of
triisopropylsilyl derivatives. Yield: 83.8% (0.7 g). 1H
NMR spectrum (400 MHz, CDCl3): 8.58 (d, 4H, PyH),
8.24 (d, 4H, PyH), 7.81 (s, 4H, ArH), 7.45-6.55 (m, 72H,
ArH), 3.01, 2.97 (2s, 8H, acetylenes). FD-MS: m/z (u
e-1): 2042 (M+, calcd 2042.49). Elem anal. calcd for
Synthesis of Td-G3-(EthynylTiPS)32. This com-
pound was prepared according to the general procedure
(see above) for the Diels-Alder reaction between tet-
raarylcyclopentadienones and aryl-ethynyl derivatives
by using Td-G2-(Ethynyl)16 and 3,4-bis-(4-(triisopro-
pylsilylethynyl)phen-1-yl)-2,5-dipyrid-2-yl-cyclopentan-
2,4-dienone. The reaction was carried out in diphenyl
ether at 200 °C for 72 h. Yield: 65%. 1H NMR spectrum
(400 MHz, CDCl3): 8.55 (d, 28H, PyH), 8.24 (d, 28H,
PyH), 7.68, 7.62, 7.59 (3s, 28H, ArH), 7.42-6.30 (m,
408H, ArH), 1.09 (s, 672H, aliph). MALDI-TOF m/e:
16804 (M+, calcd 16801.35). Elem anal. calcd for
C
1161H1164N56Si32, %: C 83.00, H 6.98, N 4.67, Si 5.35;
found: C 81.82, H 6.66, N 4.39, Si 5.11.
Synthesis of Td-G3-(Ethynyl)32 (6). A solution of
Td-G3-(EthynylTiPS)32 in THF and benzene was
treated according to the general procedure (see above)
for the desilylation of triisopropylsilyl derivatives.
Yield: 80%. 1H NMR spectrum (400 MHz, CDCl3): 8.53
(d, 28H, PyH), 8.21 (d, 28H, PyH), 7.69, 7.64, 7.57 (3s,
28H, ArH), 7.42-6.30 (m, 408H, ArH), 2.99-2.95 (m,
32H, acetylenes). MALDI-TOF m/e: 11796 (M +, calcd
11798.29). Elem anal. calcd for C873H524N56, %: C 88.88,
H 4.48, N 6.65; found: C 88.00, H 4.32, N 6.44.
C
153H92N8, %: C 89.97, H 4.54, N 5.49; found: C 88.82,
H 4.37, N 5.31.
Synthesis of Td-G2-(EthynylTiPS)16. This com-
pound was prepared according to the general procedure
(see above) for the Diels-Alder reaction between tet-
raarylcyclopentadienones and aryl-ethynyl derivatives
by using Td-G1-(Ethynyl)8 (5) and 3,4-bis-(4-(triiso-
propylsilylethynyl)phen-1-yl)-2,5-dipyrid-2-yl-cyclopen-
Synthesis of Td-G4-Ph (9). This compound was
prepared according to the general procedure (see above)
for the Diels-Alder reaction between tetraarylcyclo-
pentadienones and aryl-ethynyl derivatives by using
Td-G3-(Ethynyl)32 and 2,3,4,5-tetraphenylcyclopenta-
dienone. The reaction was carried out in diphenyl ether
at 200 °C for 120 h. Yield: 77%. 1H NMR spectrum (400
MHz, CDCl3) 8.52 (d, 28H, PyH), 8.18 (d, 28H, PyH),
7.71-7.53 (m, 60H, ArH), 7.49-6.30 (m, 1048H, ArH).
MALDI-TOF m/e: 23 283.2 (M+ + 2K+), calcd 23205.38
1
tan-2,4-dienone (1). Yield: 62.8%. H NMR spectrum
(400 MHz, CDCl3): 8.62 (d, 12H, PyH), 8.30 (d, 12H,
PyH), 7.78, 7.74, 7.68 (3s, 12H, ArH), 7.48-6.51 (m,
184H, ArH), 1.09(s, 336H, aliph). MALDI-TOF m/e: