Synthesis of Platinum–Acetylide Dendrimers
6433 – 6446
1
n˜ =2101 cmÀ1 (CꢀC); elemental analysis calcd (%) for C54H78O2P4Pt2
gave a pale-yellow solid (10.64 g, 93%). M.p. 1808C (decomp); H NMR:
(1273.27): C 50.94, H 6.17, P 9.73; found: C 51.10, H 6.02, P 9.62.
d=1.21 (dt, JHÀP =16, JHÀH =8 Hz, 108H; PCH2CH3), 2.14–2.19 (m, 72H;
PCH2CH3), 2.99 (s, 1H; ꢀCH), 3.78 (s, 12H; OCH3), 6.76 (d, J=9 Hz,
8H; C6H4OMe), 6.99 (s, 6H; Ar), 7.14 (s, 2H; Ar), 7.17 (s, 1H; Ar),
7.21 ppm (d, J=9 Hz, 8H; C6H4OMe); 13C NMR: d=8.4 (s, PCH2CH3),
Synthesis of first-generation dendrimer (3G1): A solution of first-genera-
tion dendron DW1 (382mg, 0.30 mmol) and core 7 (159 mg, 0.10 mmol)
in diethylamine (50 mL) was stirred in the presence of a catalytic amount
of CuI (ca. 5 mol%) overnight at room temperature. After removal of
the solvent, the residue was extracted with diethyl ether and the extract
was dried over Na2SO4. The solvent was removed under reduced pressure
and the residue was purified by alumina column chromatography using
dichloromethane as eluent. Recrystallization from dichloromethane/
hexane afforded a yellow solid (230 mg, 43%). M.p. 1758C (decomp);
1H NMR: d=1.20 (dt, JHÀP =17, JHÀH =8 Hz, 162H; PCH2CH3), 2.13–2.19
(m, 108H; PCH2CH3), 2.57 (s, 9H; C6CH3), 3.78 (s, 18H; OCH3), 6.76 (d,
J=9 Hz, 12H; C6H4OMe), 6.99 (s, 3H; Ar), 7.01 (s, 6H; Ar), 7.21 ppm
(d, J=9 Hz, 12H; C6H4OMe); 13C NMR: d=8.4 (s, PCH2CH3), 16.3 (vt,
16.3 (vt, N=17 Hz; PCH2CH3), 55.2(s, OCH ), 76.2(s, ꢀCH), 84.0 (s, Cꢀ
3
CH), 104.9 (t, JCÀP =15 Hz; PtCꢀ), 105.9 (t, JCÀP =15 Hz; PtCꢀ), 106.3 (t,
JCÀP =15 Hz; PtCꢀ), 108.4 (s, PtCꢀC), 108.7 (t, JCÀP =15 Hz; PtCꢀ), 108.7
(s, PtCꢀC), 109.4 (s, PtCꢀC), 109.7 (s, PtCꢀC), 113.5 (s, C6H4OMe), 121.3
À
À
À
(s, Ar Cipso Cꢀ), 122.5 (s, Ar Cipso Cꢀ), 127.8 (s, Ar Cipso Cꢀ), 128.0 (s,
À
À
Ar Cipso Cꢀ), 128.7 (s, Ar Cipso Cꢀ), 130.5 (s, Ar), 130.6 (s, Ar), 131.1 (s,
À
Ar), 131.9 (s, C6H4OMe), 134.0 (s, Ar), 157.3 ppm (s, Ar Cipso OMe);
31P NMR: d=10.8 (s, JPÀPt =2381 Hz, 8P), 11.0 ppm (s, JPÀPt =2374 Hz,
4P); IR (KBr): n˜ =2095 cmÀ1 (CꢀC); elemental analysis calcd (%) for
C144H218O4P12Pt6 (3555.48): C 48.65, H 6.18, P 10.45; found: C 48.63, H
6.04, P 10.19.
N=17 Hz; PCH2CH3), 20.6 (s, C6CH3), 55.2(s, OCH 3), 105.0 (t, JCÀ
=
P
15 Hz; PtCꢀ), 106.1 (t, JCÀP =15 Hz; PtCꢀ), 106.7 (t, JCÀP =15 Hz; PtCꢀ),
Synthesis of second-generation dendrimer (3G2): Second-generation den-
dron DW2 (533 mg, 150 mmol) and core 7 (79.5 mg, 50 mmol) were react-
ed in a similar manner to that of the preparation of the first-generation
dendrimer 3G1. The crude product that was obtained by alumina column
chromatography was dissolved in dichloromethane and precipitated with
methanol to give a pale-yellow solid (230 mg, 38%). M.p. 195–2108C
(decomp); 1H NMR: d=1.21 (dt, JHÀP =16, JHÀH =8 Hz, 378H;
PCH2CH3), 2.15–2.19 (m, 252H; PCH2CH3), 2.57 (s, 9H; C6CH3), 3.77 (s,
36H; OCH3), 6.76 (d, J=9 Hz, 24H; C6H4OMe), 6.99 (s, 27H; Ar),
7.21 ppm (d, J=9 Hz, 24H; C6H4OMe); 13C NMR: d=8.4 (s, PCH2CH3),
16.3 (vt, N=17 Hz; PCH2CH3), 20.7 (s, C6CH3), 55.2(s, OCH 3), 104.9 (t,
JCÀP =15 Hz; PtCꢀ), 106.2(t, JCÀP =15 Hz; PtCꢀ), 108.7 (s, PtCꢀC), 109.4
107.5 (s, PtCꢀC), 108.7 (s, PtCꢀC), 109.4 (s, PtCꢀC), 109.7 (s, PtCꢀC),
À
113.5 (s, C6H4OMe), 114.4 (t, JCÀP =15 Hz; PtCꢀ), 121.5 (s, Ar Cipso Cꢀ),
À
À
125.4 (s, Ar Cipso Cꢀ), 127.9 (s, Ar Cipso-Cꢀ), 128.1 (s, Ar Cipso Cꢀ), 130.4
À
(s, Ar), 130.6 (s, Ar), 131.9 (s, C6H4OMe), 135.6 (s, Ar Cipso CH3),
157.2ppm (s, Ar Cipso OMe); 31P NMR: d=10.9 (s, JPÀPt =2381 Hz, 12P),
À
11.1 ppm (s, JPÀPt =2392 Hz, 6P); IR (KBr): n˜ =2095 cmÀ1 (CꢀC); ele-
mental analysis calcd (%) for C684H1058O16P60Pt30 (5300.21): C 48.27, H
6.28, P 10.52; found: C 48.37, H 6.14, P 10.26.
Synthesis of building block (8): 1,3-Diethynyl-5-(triisopropylsilylethynyl)-
benzene 4 (5.57 g, 18.17 mmol) and [PtCl2(PEt3)2] (22.82 g, 45.43 mmol)
were dissolved in piperidine (600 mL). After a catalytic amount of CuI
(ca. 5 mol%) was added, the reaction mixture was placed under reflux
for one week. The solvent was evaporated and the residue was extracted
with diethyl ether. The extract was dried over Na2SO4 and the solvent
was evaporated again. The residue was purified by alumina column chro-
matography with benzene followed by recrystallization from ethanol to
give pale-yellow needles (16.63 g, 74%). 1H NMR: d=1.13 (s, 21H;
SiC3H7), 1.20 (dt, JHÀP =16, JHÀH =8 Hz, 36H; PCH2CH3), 2.02–2.09 (m,
24H; PCH2CH3), 7.07 (b, 1H; Ar), 7.11 ppm (d, J=1 Hz, 2H; Ar);
13C NMR: d=8.0 (s, PCH2CH3), 11.3 (s, JCÀSi =56 Hz; SiCH(CH3)2), 14.5
À
(s, PtCꢀC), 109.5 (s, PtCꢀC), 113.5 (s, C6H4OMe), 121.5 (s, Ar Cipso Cꢀ),
À
À
125.4 (s, Ar Cipso Cꢀ), 128.0 (s, Ar Cipso Cꢀ), 130.5 (s, Ar), 131.9 (s,
À
À
C6H4OMe), 135.7 (s, Ar Cipso CH3), 157.3 ppm (s, Ar Cipso OMe);
31P NMR: d=10.9 (s, JPÀPt =2381 Hz, 36P), 11.1 ppm (s, JPÀPt =2394 Hz,
6P); IR (KBr): n˜ =2093 cmÀ1 (CꢀC); elemental analysis calcd (%) for
C483H750O12P42Pt21 (12146.84): C 47.76, H 6.22, P 10.71; found: C 47.94, H
6.12, P 10.66.
Synthesis of protected third-generation dendron (10): Second-generation
dendron DW2 (8.26 g, 2.32 mmol) and building block
8 (1.40 g,
(vt, N=17 Hz; PCH2CH3), 18.7 (s, SiCH(CH3)2), 83.2(t, JCÀP =15, JCÀ
=
1.13 mmol) were reacted in a similar manner to that of the preparation
of the protected first-generation dendron 6. Alumina column chromatog-
raphy was performed with dichloromethane as eluent, and recrystalliza-
tion from toluene/ethanol gave a pale-yellow solid (7.47 g, 80%). M.p.
2008C (decomp); 1H NMR: d=1.12(s, 21H; SiC 3H7), 1.21 (dt, JHÀP =16,
JHÀH =8 Hz, 252H; PCH2CH3), 2.15–2.19 (m, 168H; PCH2CH3), 3.78 (s,
24H; OCH3), 6.76 (d, J=9 Hz, 16H; C6H4OMe), 6.99 (s, 18H; Ar), 7.12
(s, 3H; Ar), 7.21 ppm (d, J=9 Hz, 16H; C6H4OMe); 13C NMR: d=8.4 (s,
PCH2CH3), 11.4 (s, SiCH), 16.3 (vt, N=17 Hz; PCH2CH3), 18.7 (s,
Pt
1437 Hz; PtCꢀ), 90.0 (s, SiCꢀ), 100.9 (t, JCÀP =2, JCÀPt =408 Hz; PtCꢀC),
À
À
107.2(s, SiC ꢀC), 123.0 (s, Ar Cipso Cꢀ), 128.50 (s, JCÀPt =35 Hz; Ar Cipso
Cꢀ), 131.2(s, Ar), 133.3 ppm (s, Ar); 31P NMR: d=14.9 ppm (s, JPÀ
=
Pt
2385 Hz); IR (KBr): n˜ =2111 cmÀ1 (CꢀC); elemental analysis calcd (%)
for C45H84SiP4Cl2Pt2 (1238.21): C 43.65, H 6.84, P 10.01, Cl 5.73; found: C
43.94, H 6.83, P 10.24, Cl 5.63.
Synthesis of protected second-generation dendron (9): First-generation
dendron DW1 (10.06 g, 7.90 mmol) and building block
8 (4.89 g,
SiCH(CH3)2), 55.2(s, OCH ), 89.5 (s, SiCꢀ), 104.9 (t, JCÀP =15 Hz; PtCꢀ),
3.95 mmol) were reacted in a similar manner to that of the preparation
of the protected first-generation dendron 6. Alumina column chromatog-
raphy was performed with benzene/CH2Cl2 (1:1) as eluent. Recrystalliza-
tion from dichloromethane/hexane gave a pale-yellow solid (12.08 g,
3
106.3 (t, JCÀP =15 Hz; PtCꢀ), 107.6 (s, SiCꢀC), 108.7 (s, PtCꢀC), 109.4 (s,
À
PtCꢀC), 109.5 (s, PtCꢀC), 113.5 (s, C6H4OMe), 121.5 (s, Ar Cipso Cꢀ),
À
À
À
122.8 (s, Ar Cipso Cꢀ), 128.0 (s, Ar Cipso Cꢀ), 128.6 (s, Ar Cipso Cꢀ),
82%). M.p. 148 8C; 1H NMR: d=1.12(s, 21H; SiC 3H7), 1.21 (dt, JHÀ
=
130.5 (s, Ar), 131.0 (s, Ar), 131.9 (s, C6H4OMe), 133.5 (s, Ar), 157.3 ppm
P
(s, Ar Cipso OMe); 31P NMR: d=10.8 (s, JPÀPt =2382 Hz, 24P), 11.0 ppm
À
16, JHÀH =8 Hz, 108H; PCH2CH3), 2.15–2.19 (m, 72H; PCH2CH3), 3.78
(s, 12H; OCH3), 6.76 (d, J=9 Hz, 8H; C6H4OMe), 6.98 (s, 6H; Ar), 7.12
(s, 3H; Ar), 7.21 ppm (d, J=9 Hz, 8H; C6H4OMe); 13C NMR: d=8.35 (s,
PCH2CH3), 11.4 (s, JCÀSi =56 Hz; SiCH), 16.3 (vt, N=17 Hz; PCH2CH3),
(s, 4P); IR (KBr): n˜ =2094 cmÀ1 (CꢀC); elemental analysis calcd (%) for
C333H518O8SiP28Pt14 (8276.24): C 48.33, H 6.31, P 10.48; found: C 48.10, H
6.27, P 10.60.
18.7 (s, SiCH(CH3)2), 55.2(s, OCH 3), 89.4 (s, SiCꢀ), 104.9 (t, JCÀ
=
P
Synthesis of third-generation dendron (DW3): Protected third-generation
dendron 10 (2.56 g, 0.31 mmol) was treated with a solution of Bu4NF
(0.37 mL, 0.37 mmol) in THF (1.0m) in a similar manner to that of the
preparation of the first-generation dendron DW1. The crude product was
purified by alumina column chromatography with dichloromethane con-
taining 0.25% of ethyl acetate as eluent, and recrystallization from tolu-
ene/ethanol gave a yellow solid (2.31 g, 92%). M.p. 1858C (decomp);
1H NMR: d=1.21 (dt, JHÀP =16, JHÀH =8 Hz, 252H; PCH2CH3), 2.15–2.19
(m, 168H; PCH2CH3), 3.00 (s, 1H; ꢀCH), 3.78 (s, 24H; OCH3), 6.76 (d,
J=9 Hz, 16H; C6H4OMe), 6.99 (s, 18H; Ar), 7.15 (s, 2H; Ar), 7.17 (s,
1H; Ar), 7.21 ppm (d, J=9 Hz, 16H; C6H4OMe); 13C NMR: d=8.4 (s,
15 Hz; PtCꢀ), 106.0 (t, JCÀP =15 Hz; PtCꢀ), 106.3 (t, JCÀP =15 Hz; PtCꢀ),
107.6 (s, SiCꢀC), 108.4 (t, JCÀP =15 Hz; PtCꢀ), 108.7 (s, PtCꢀC), 109.4 (s,
À
PtCꢀC), 109.6 (s, PtCꢀC), 113.5 (s, C6H4OMe), 121.5 (s, Ar Cipso Cꢀ),
À
À
À
122.8 (s, Ar Cipso Cꢀ), 127.9 (s, Ar Cipso Cꢀ), 128.0 (s, Ar Cipso Cꢀ),
À
128.5 (s, Ar Cipso Cꢀ), 130.5 (s, Ar), 131.0 (s, Ar), 131.9 (s, C6H4OMe),
133.5 (s, Ar), 157.3 ppm (s, Ar Cipso OMe); 31P NMR: d=10.8 (s, JPÀ
=
À
Pt
2381 Hz, 8P), 11.0 ppm (s, JPÀPt =2374 Hz, 4P); IR (KBr): n˜ =2095 cmÀ1
(CꢀC); elemental analysis calcd (%) for C153H238O4SiP12Pt6 (3711.82): C
49.51, H 6.46, P 10.01; found: C 49.61, H 6.29, P 10.12.
Synthesis of second-generation dendron (DW2): Protected second-gener-
ation dendron 9 (11.91 g, 3.21 mmol) was treated with a solution of
Bu4NF (3.9 mL, 3.9 mmol) in THF (1.0m) in a similar manner to that of
preparation of the first-generation dendron DW1. The crude product was
purified by alumina column chromatography with benzene/dichlorome-
thane (1:9) as eluent, and recrystallization from dichloromethane/ethanol
PCH2CH3), 16.3 (vt, N=17 Hz; PCH2CH3), 55.2(s, OCH 3), 76.2(s,
ꢀ
CH), 84.0 (s, CꢀCH), 104.9 (t, JCÀP =15 Hz; PtCꢀ), 105.9 (t, JCÀP =15 Hz;
PtCꢀ), 106.3 (t, JCÀP =15 Hz; PtCꢀ), 106.4 (t, JCÀP =15 Hz; PtCꢀ), 108.5
(s, PtCꢀC), 108.7 (s, PtCꢀC), 108.7 (t, JCÀP =15 Hz; PtCꢀ), 109.4 (s, PtCꢀ
C), 109.5 (s, PtCꢀC), 109.7 (s, PtCꢀC), 113.5 (s, C6H4OMe), 121.3 (s, Ar
Chem. Eur. J. 2004, 10, 6433 – 6446
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
6443