Li et al.
dith iazepan e (23), an d 4-[4-[3,7-Bis[4-[4-(1,2,5-dith iazepan -
5-yl)p h en yleth yn yl]p h en yl]-5-(4-iod op h en yl)a d a m a n ta n -
1-yl]p h en yleth yn yl]ben zoic Acid Meth yl Ester (24). A
thick-walled reaction tube was charged with ester (21, 25 mg,
0.026 mmol), 5-(4-ethynylphenyl)-1,2,5-dithiazepane (17, 18.0
mg, 0.104 mmol), Pd(PPh3)2Cl2 (5.0 mg, 0.071 mmol), and CuI
(3.0 mg, 0.015 mmol) in triethylamine (2 mL) and tetrahydro-
furan (8 mL). The suspension was flushed with N2 and capped
with a Teflon screwcap. The mixture was heated with stirring
at 50-55 °C for 20 h and then filtered, and the solid was
washed with CHCl3 (30 mL). The filtrate was evaporated to
dryness, and the residue was purified by chromatography.
Elution with 1:1 CHCl3/hexanes first gave alkyne dimer 23
(6.0 mg, 18%) as a colorless solid, which was pure by TLC and
4-[4-[3,5,7-T r is -[4-(4-a c e t y ls u lfa n y lm e t h y lp h e n y l-
et h yn yl)p h en yl]a d a m a n t a n -1-yl]p h en ylet h yn yl]b en zo-
ic Acid Meth yl Ester (26). A thick-walled reaction tube was
charged with 4-[4-[3,5,7-tris(4-iodophenyl)adamantan-1-yl]-
phenylethynyl]benzoic acid methyl ester (21, 25 mg, 0.026
mmol), 1-[4-(S-acetylthiomethyl)phenyl]acetylene (13, 19.5 mg,
0.102 mmol), Pd(PPh3)2Cl2 (5 mg, 0.071 mmol), CuI (3 mg,
0.015 mmol), triethylamine (2 mL), and THF (8 mL). The
mixture was flushed with N2 and capped with a Teflon
screwcap. The mixture was heated with stirring at 60-65 °C
for 20 h and then filtered, and the solid was washed with CH2-
Cl2 (50 mL). The filtrate was evaporated to dryness, and the
residue was purified by chromatography. Elution with 1:1 CH2-
Cl2/hexanes gave 26 (5.6 mg, 19%) as a white solid, which was
1
1
pure by TLC and NMR: dec ∼130 °C (PHB, yellow solid); H
NMR: mp >250 °C; H NMR δ 3.08 (t, J ) 5.6 Hz, 8H), 3.97
NMR (CDCl3, 500 MHz) δ 2.17 (s, 12H), 2.36 (s, 9H), 3.93 (s,
3H), 4.12 (s, 6H), 7.26 (d, J ) 8.5 Hz, 6H), 7.45 (d, J ) 8.0 Hz,
6H), 7.46 (d, J ) 8.5 Hz, 6H), 7.49 (d, J ) 9.0 Hz, 2H), 7.52 (d,
J ) 8.5 Hz, 6H), 7.55 (d, J ) 8.5 Hz, 2H), 7.59 (d, J ) 8.5 Hz,
2H), 8.02 (d, J ) 8.5 Hz, 2H); 13C NMR (75 MHz) δ 30.31,
33.24, 39.30, 39.38, 46.77, 52.21, 88.54, 88.98, 89.49, 92.28,
120.60, 121.15, 122.26, 125.06, 125.18, 128.03, 128.83, 129.36,
129.48, 131.46, 131.69, 131.78, 131.82, 137.82, 149.16, 149.76,
166.56, 194.94; MS calcd for C77H64O5S3 (M + 2) 1164.4, found
1164.4.
(t, J ) 5.6 Hz, 8H), 6.56 (d, J ) 9.0 Hz, 4H), 7.39 (d, J ) 9.0
Hz, 4H); 13C NMR δ 36.63, 52.49, 77.20, 82.06, 109.20, 111.12,
134.12, 146.77; MS calcd for C24H25N2S4 (M + 1) 469.1, found
469.1. Continued elution gave the incompletely coupled ester
24 as a colorless solid (4.1 mg, 13%), which was pure by TLC
and NMR: mp ∼180-225 °C (PHB, dark brown to dark red
solid); 1H NMR (CDCl3, 500 MHz) δ 2.13 (s, 6H), 2.15 (s, 6H),
3.09 (t, J ) 5.5 Hz, 8H), 3.93 (s, 3H), 3.99 (t, J ) 5.5 Hz, 8H),
6.60 (d, J ) 9.0 Hz, 4H), 7.24 (d, J ) 8.5 Hz, 2H), 7.41 (d, J )
9.3 Hz, 4H), 7.42 (d, J ) 9.3 Hz, 4H), 7.47 (d, J ) 8.0 Hz, 2H),
7.49 (d, J ) 8.5 Hz, 4H), 7.54 (d, J ) 8.5 Hz, 2H), 7.59 (d, J )
8.5 Hz, 2H), 7.68 (d, J ) 8.5 Hz, 2H), 8.02 (d, J ) 8.5 Hz, 2H);
13C NMR δ 29.70, 36.74, 39.22, 39.38, 46.81, 52.23, 52.44,
87.31, 88.53, 90.13, 91.61, 92.31, 110.53, 111.12, 120.59,
122.03, 124.94, 125.20, 127.24, 129.51, 131.38, 131.49, 131.84,
133.18, 137.47, 146.30, 148.30, 148.78, 149.80, 166.58; MS
calcd for C68H60IN2O2S4 (M + 1) 1191.3, found 1191.3. Con-
tinued elution gave 22 (3.2 mg, 10%) as a pale white solid,
which was pure by TLC and NMR: dec ∼175-210 °C (PHB,
yellow to dark yellow solid); 1H NMR (CDCl3, 500 MHz) δ 2.16
(s, 12H), 3.09 (t, J ) 5.5 Hz, 12H), 3.93 (s, 3H), 3.98 (t, J )
5.5 Hz, 12H), 6.59 (d, J ) 8.5 Hz, 6H), 7.41 (d, J ) 9.0 Hz,
6H), 7.44 (d, J ) 8.5 Hz, 6H), 7.49 (d, J ) 8.0 Hz, 8H), 7.54 (d,
J ) 8.5 Hz, 2H), 7.59 (d, J ) 8.5 Hz, 2H), 8.04 (d, J ) 8.5 Hz,
2H); 13C NMR δ 29.68, 36.75, 39.26, 46.86, 52.23, 52.44, 77.20,
87.36, 88.47, 90.06, 110.57, 111.12, 120.52, 121.95, 125.00,
125.24, 128.12, 129.50, 131.37, 131.49, 131.82, 133.18, 146.29,
148.49, 149.98, 166.61; MS calcd for C80H72N3O2S6 (M + 1)
1298.4, found 1298.4.
4-[[4-[3,5,7-T r is [4-(4-a c e t y ls u lfa n y lm e t h y lp h e n y l-
eth yn yl)p h en yleth yn yl]p h en yl]a d a m a n ta n -1-yl]p h en yl-
eth yn yl]ben zoic Acid Meth yl Ester (27). A thick-walled
reaction tube was charged with ester 21 (25.0 mg, 0.0270
mmol), thioacetic acid S-[4-(4-ethynylphenylethynyl)benzyl]
ester (16, 37.9 mg, 0.128 mmol), Pd(PPh3)2Cl2 (5.0 mg, 0.071
mmol), CuI (3.0 mg, 0.015 mmol), triethylamine (2 mL), and
THF (8 mL). The mixture was flushed with N2 and capped
with a Teflon screwcap. The mixture was heated with stirring
at 50-55 °C for 20 h and then filtered, and the solid was
washed with CH2Cl2 (50 mL). The filtrate was evaporated to
dryness, and the residue was purified by chromatography.
Elution with 1:1 CH2Cl2/hexanes gave 27 (3.5 mg, 10%) as a
pale white solid, which was pure by TLC and NMR: dec ∼142
1
°C (PHB, yellow solid); H NMR (CDCl3, 500 MHz) δ 2.19 (s,
12H), 2.36 (s, 9H), 3.93 (s, 3H), 4.12 (s, 6H), 7.28 (d, J ) 8.0
Hz, 6H), 7.46 (d, J ) 8.5 Hz, 6H), 7.49 (d, J ) 9.0 Hz, 6H),
7.50 (s, 18H), 7.51 (d, J ) 8.5 Hz, 2H), 7.54 (d, J ) 8.0 Hz,
6H), 7.56 (d, J ) 8.5 Hz, 2H), 7.59 (d, J ) 8.0 Hz, 2H), 8.02 (d,
J ) 8.5 Hz, 2H); 13C NMR (CDCl3, 125 MHz) δ 30.33, 33.26,
39.38, 46.80, 52.22, 88.58, 89.05, 89.36, 90.94, 91.14, 92.27,
96.11, 120.68, 121.04, 122.00, 122.98, 123.16, 125.15, 128.06,
128.90, 129.51, 131.52, 131.80, 131.83, 138.15, 149.37, 149.73,
166.57, 194.89; MS calcd for C101H74O5S3 (M) 1462.47, found
1462.4. Anal. Calcd for C101H74O5S3‚5H2O: C, 78.06; H, 5.45.
Found: C, 77.71; H, 5.41.
4-[[4-[3,5,7-Tr is-[4-[4-[4-(1,2,5-d ith ia zep a n -5-yl)p h en yl-
eth yn yl]p h en yleth yn yl]p h en yl]a d a m a n ta n -1-yl]p h en yl-
eth yn yl]ben zoic Acid Meth yl Ester (25). A thick walled
reaction tube was charged with 4-[4-[3,5,7-tris-(4-iodophenyl)-
adamantan-1-yl]phenylethynyl]benzoic acid methyl ester (21,
25.0 mg, 0.026 mmol), 5-[4-(4-ethynylphenylethynyl)phenyl]-
1,2,5-dithiazepane (18, 34.4 mg, 0.103 mmol), Pd(PPh3)2Cl2 (5.0
mg, 0.071 mmol), and CuI (3.0 mg, 0.015 mmol) in triethyl-
amine (2 mL) and tetrahydrofuran (8 mL). The suspension was
flushed with N2 and capped with a Teflon screwcap. The
mixture was heated with stirring at 50-55 °C for 20 h and
then filtered, and the solid was washed with CHCl3 (30 mL).
The filtrate was evaporated to dryness, and the residue was
purified by chromatography with 1:1 CHCl3/hexanes as an
eluent to give 25 (3.2 mg, 8%) as a pale white solid, which
was pure by TLC and NMR: dec ∼220 °C (PHB, orange solid);
1H NMR (CDCl3, 500 MHz) δ 2.19 (s, 12H), 3.10 (t, J ) 5.5
Hz, 12H), 3.93 (s, 3H), 3.99 (t, J ) 5.5 Hz, 12H), 6.61 (d, J )
9.0 Hz, 6H), 7.41 (d, J ) 9.0 Hz, 6H), 7.46 (d, J ) 8.5 Hz, 6H),
7.48 (d, J ) 8.5 Hz, 12H), 7.50 (d, J ) 8.5 Hz, 2H), 7.54 (d, J
) 8.0 Hz, 6H), 7.56 (d, J ) 8.5 Hz, 2H), 7.59 (d, J ) 8.5 Hz,
2H), 8.02 (d, J ) 8.5 Hz, 2H); 13C NMR (CDCl3, 125 MHz) δ
29.68, 36.74, 39.38, 46.82, 52.49, 81.35, 87.41, 89.26, 90.78,
92.35, 96.12, 110.27, 111.16, 121.16, 122.27, 123.93, 125.13,
129.52, 131.18, 131.47, 131.72, 133.27, 146.54, 149.26, 166.60;
MS calcd for C104H84N3O2S6 (M + 1) 1598.5, found 1598.5. Anal.
Calcd for C104H83N3O2S6‚6H2O: C, 73.16; H, 5.61; N, 2.46.
Found: C,73.22; H, 5.66; N, 2.54.
Atom ic F or ce Micr oscop y Exp er im en ts. AFM measure-
ments were carried out with a Nanoscope IIIa Multimode AFM
(Digital Instruments, Santa Barbara, CA) using a 10 µm
scanner. Tapping mode AFM (TMAFM) scans were performed
in air with NANOSENSORS silicon cantilevers/tips: type
NCH, cantilever resonance frequency f0 ) 289-332 kHz and
force constant 24.0-37.0 N/m.
The instrument was operated at frequencies slightly lower
than the natural resonance frequency in air. All data were
recorded in height mode. Set point values were chosen so that
the interaction of the tip and sample provided a good compro-
mise between stability and resolution, without damaging the
tip or the sample. Scan rates ranged from 1 to 3 Hz. Images
were taken at a 512 × 512-pixel resolution to increase the
detail in the images. All TMAFM studies were carried out on
freshly cleaved muscovite mica, grade V-4 (Structure Probe,
Inc.).
Sa m p le P r ep a r a tion . Spectroscopic grade solvents were
used for sample preparation. Ester 27 on Mica . One drop of
a 0.25 or 1.0 µM solution of ester 27 in CH2Cl2 was spin-coated
onto freshly cleaved mica (cleaved with Scotch tape) for 15-
4868 J . Org. Chem., Vol. 68, No. 12, 2003