Spin Exchange Interaction through Phenylene-Ethynylene Bridge
-CH3) Anal. Calcd for C13H19O2N2Br: C, 49.52; H, 6.03; N, 8.88;
p r essu r e of n itr ogen ). After heating for 24 h at 115 °C, the
reaction mixture was poured into 50 mL of pentane. The
precipitate was filtered off and separated by chromatography
through a silica gel column using CH2Cl2/pentane, 1/4, as
eluent to give 4.85 g of the iodide derivative 11.Yield: 97%.
1H NMR (CDCl3): δ 7.64 and 7.19 (dd, 4H, -PhH); 0.25 (s,
9H, -SiCH3).
O, 10.16. Found: C, 49.45; H, 5.99; N, 8.92; O, 10.18.
1,3-Dih ydr oxy-2-(p-eth yn ylph en yl)-4,4,5,5-tetr am eth yl-
2-im id a zolin e (6). The procedure used to obtain 5 was
followed with 0.966 g of ethynylbenzaldehyde (4) and 1 g of
bis(hydroxylamine) (2) to give 1.37 g of the hydrido adduct 6.
Yield: 78%. Mp: 211 °C. 1H NMR (DMSO-d6): δ 7.8 (s, 2H,
-OH); 7.45 (dd, 4H, -PhH); 4.49 (s, 1H, -HC5); 4.13 (s, 1H,
-CtCH); 1.06(s, 6H, -CH3); 1.02(s, 6H, -CH3). Anal. Calcd
for C15H20O2N2: C, 69.23; H, 7.69; N, 10.77; O, 12.30. Found:
C, 68.95; H, 7.56; N, 10.66; O, 12.35.
Dim er In ter m ed ia te 12. The procedure used to obtain 3
was followed with 11 (3 g, 10 mmol), 6 (2.3 g, 0.9 mmol), 118
mg of TPP, 16 mg of PdCl2, 18 mg of CuOAc2, and 100 mL of
triethylamine. The crude material was purified on a silica gel
column using CH2Cl2/EtOH, 9.5/0.5, as eluent to give 3.5 g of
Dim er IN-2p-IN (7). The procedure used to obtain 3 was
followed with 5 (0.44 g, 1.39 mmol), 6 (0.363 g, 1.39 mmol), 25
mg of TPP, 4 mg of PdCl2, 5 mg of CuOAc2, and 30 mL of
triethylamine. The crude material was purified on a silica gel
column using CH2Cl2/EtOH, 9/1, as eluent to give 0.5 g of the
1
the yellow intermediate 12′. Yield: 95%. H NMR (CDCl3): δ
8.24 and 7.54 (dd, 4H, -Ph2H); 7.47 (s, 4H, -Ph1H); 1.36 (s,
6H, -CH3); 1.34 (s, 6H, -CH3); 0.25 (s, 9H, -SiCH3). Depro-
tection: 12′ (3 g, 7 mmol) was dissolved in 10 mL of THF, and
TBAF (0.23 g, 0.9 mmol) was slowly added leading to a black
solution. After 10 min, the reaction was filtered through a plug
of silica gel. The solvent was evaporated and the crude product
was separated by chromatography through a silica gel column
using CH2Cl2/e´thanol, 9.5/0.5 as eluent, to give 2.1 g of the
1
yellow intermediate 7′. Yield: 73%. H NMR (CDCl3): δ 8.15
and 7.55 (dd, 8H, -PhH); 1.35 (s, 12H, -CH3); 1.30 (s, 12H,
-CH3). Oxidation: A solution of (7′) (100 mg, 0.22 mmol) in
10 mL of CH2Cl2 was stirred at room temperature during 2 h
with MnO2 (190 mg, 10 eq). After filtration, the dark red
solution was concentrated, and the crude material was purified
by preparative chromatography (eluent: CH2Cl2/EtOH 9.5/0.5).
Recrystallization in hexane/CH2Cl2 yields 95 mg (96%) of red
crystals (7). Mp: 180 °C. Anal. Calcd for C14H32O2N4: C, 73.68;
H, 7.45; O, 7.01; N, 12.28. Found: C, 73.78; H, 7.05; O, 7.25;
N, 12.30.
1
yellow deprotected dimer (12). Yield: 85%. H NMR (CDCl3):
δ 8.25 and 7.54 (dd, 4H, -Ph2H); 7.47 (s, 4H, -Ph1H); 3.2 (s,
1H, -CtCH); 1.36 (s, 6H, -CH3); 1.34 (s, 6H, -CH3).
P en ta m er IN-5p-IN (13). The procedure used to obtain 3
was followed with 1,4-dibromo-2.5-bis(tetradecanoxy)benzene
(1.5 g, 2.3 mmol), 12 (1.78 g, 5.3 mmol), 60 mg (5% mol) of
TPP, 8 mg (1% mol) of PdCl2, 9 mg (1% mol) of CuOAc2, and
50 mL of triethylamine. The crude material was purified on a
silica gel column using CH2Cl2/ethanol, 9.5/0.5, as eluent, to
give 1.4 g of yellow powder (13′). Yield: 53%. 1H NMR
(CDCl3): δ 8.29 and 7.54 (dd, 8H, -Ph2H); 7.50 (s, 8H, -Ph1H);
7,00 (s, 2H, PhOC12); 4.03 (t, 4H, -OCH2- R ether); 1.86 (q,
4H, -CH2- â ether); 1.39 (s, 12H, -CH3); 1.33 (s, 12H, -CH3);
1.25 (s, 44H, -CH2- δ); 0.87 (t, 6H, -CH3 t). Anal. Calcd for
Tr im er IN-3p-IN (8). The procedure used to obtain 3 was
followed with 1,4-dibromo-2,5-bis(dodecanoxy)benzene (1 g, 1
equiv), 6 (0.950 g, 2.2 equiv), 43 mg of TPP, 6 mg of PdCl2, 7
mg of CuOAc2, and 50 mL of triethylamine. The crude material
was purified on a silica gel column using CH2Cl2/EtOH, 9/1,
as eluent to give 1.12 g of the yellow intermediate 8′. Yield:
1
73%. H NMR (CDCl3): δ 8.3 and 7.55 (dd, 8H, -PhH1); 7 (s,
2H, -PhOC12); 4.05 (t, 4H, -OCH2 R ether); 1.86 (q, 4H, -CH2-
â ether); 1.39 (s, 12H, -CH3); 1.33 (s, 12H, -CH3); 1.25 (s,
36H, -CH2- δ); 0.86 (t, 6H, -CH3t). Oxidation: The procedure
to obtain 7 was followed with 8′ (200 mg) and 10 equivalent
of MnO2 in 10 mL of CH2Cl2. Recrystallization in hexane/CH2-
Cl2 yields 170 mg (85%) of red crystals (8). Mp: 102 °C. Anal.
Calcd for C60H84O4N4: C, 77.92; H, 9.09; O, 6.92; N, 6.06.
Found: C, 77.85; H, 9.23; O, 6.87; N, 5.92.
C
80H102O4N4: C, 81.21; H, 8.63; O, 5.41; N, 4.73. Found: C,
79.27; H, 8.60; O, 5.50; N, 4.52. Oxidation: A solution of 13′
(150 mg, 1 equiv) in 10 mL of CH2Cl2 was stirred at room
temperature during 2 h with MnO2 (20 equiv). After filtration,
the dark red solution was concentrated, and the crude material
was purified by preparative chromatography (eluent: CH2Cl2/
EtOH 9.5/0.5). Recrystallization in heptane/CH2Cl2 yields 133
mg of red crystals (13). Yield: 89%. Mp: 169 °C. Anal. Calcd
for C80H100O4N4: C, 81.35; H, 8.47; O, 5.42; N, 4.74. Found: C,
80.62; H, 8.43; O, 5.46; N, 4.53.
1-(4-Br om op h en yl)-3,3-d ieth yltr ia zen e (9). 4-Bromoa-
niline (10.32 g, 60 mmol), 7.5 mL of chlorhydrique acid, and 9
mL of water were charged and stirred in a vessel frozen (0
°C) with an ice-salt bath. A cold solution of sodium nitrite
(4.54 g, 66 mmol) in 7.5 mL of water was slowly added. The
mixture was stirred for 30 min, keeping the temperature under
0 °C. The diazonium solution was then slowly added to a frozen
mixture of potassium carbonate (12.44 g, 90 mmol) and
diethylamine (6.58 g, 90 mmol) in 120 mL of water and stirred
for 30 min, while the temperature was allowed to increase to
room temperature. The mixture was extracted with ether. The
organic fraction was washed with water, dried over Na2SO4,
and evaporated. The crude material was purified by silica gel
chromatography using heptane/CH2Cl2, 2/1, as eluent to give
14 g pure triazene 9 (yellow liquid). Yield: 91%. 1H NMR
(CDCl3): δ 7.37 (dd, 4H, -PhH); 3.76 (q, 4H, -CH2-); 1.27 (t,
6H, -CH3).
1-(4-T r im e t h y ls ily le t h y n y lp h e n y l)-3,3-d ie t h y lt r i-
a zen e (10). The procedure used to obtain 3 was followed with
9 (8 g, 1 equiv), 3.82 mL (1.5 equiv) of TMSA, 0.2 g (5% mol)
of TPP, 28 mg (1% mol) of PdCl2, 31 mg (1% mol) of CuOAc2,
and 50 mL of triethylamine. The crude material was purified
on a silica gel column using CH2Cl2/pentane, 1/2, as eluent to
give 6.5 g of orange liquid (10). Yield: 76%. 1H NMR (CDCl3):
δ 7.42 (dd, 4H, -PhH); 3.77 (q, 4H, -CH2-); 1.27 (t, 6H,
-CH3); 0.25 (s, 9H, -SiCH3).
Tr im er IN-pm p-IN (X ) H, Y ) H) (14). The procedure
used to obtain 3 was followed with 1,3-dibromobenzene (0.5
g, 1 equiv), 6 (1.21 g, 2.2 equiv), 61 mg (5% mol) of TPP, 8.5
mg (1% mol) of PdCl2, 9.5 mg (1% mol) of CuOAc2, and 40 mL
of triethylamine. The crude material was purified on a silica
gel column using CH2Cl2/ethanol, 9/1 as eluent, to give 0.83 g
1
of yellow powder (14′). Yield: 71%. H NMR (DMSO): δ 8.04
and 7.68 (dd, 8H, -Ph1H); 7.79 (t, 1H, -Ph2HB); 7,65 (dd, 2H,
Ph2HA); 7.55 (t, 1H, Ph2Hc), 1.18 (s, 12H, -CH3); 1.16 (s, 12H,
-CH3). Oxidation: A solution of 14′ (400 mg, 1 equiv) in 10
mL of CH2Cl2 was stirred at room temperature during 2 h with
MnO2 (20 equiv). After filtration, the dark red solution was
concentrated, and the crude material was purified by prepara-
tive chromatography (eluent: CH2Cl2/EtOH 9.5/0.5). Recrys-
tallization in heptane/CH2Cl2 yields 360 mg of red crystals (14).
Yield: 90%. Mp: 115 °C. Anal. Calcd for C36H36O2N2: C, 77.69;
H, 6.47; O, 5.75; N, 10.07. Found: C, 77.48; H, 6.46; O, 5.77;
N, 10.28.
Tr im er IN-pm sp-IN (X ) CH3, Y OC12) (15). The proce-
dure used to obtain 3 was followed with 1,3-dibromo-2-methyl-
5-dodecanoxybenzene (0.646 g, 1 equiv), 6 (0.852 g, 2.2 equiv),
43 mg (5% mol) of TPP, 6 mg (1% mol) of PdCl2, 6.5 mg (1%
mol) of CuOAc2, and 40 mL of triethylamine. The crude
material was purified on a silica gel column using CH2Cl2/
ethanol, 9/1 as eluent, to give 0.765 g of yellow powder (15′).
Yield: 68%. 1H NMR (CDCl3): δ 8.29 and 7.60 (dd, 8H,
-Ph1H); 6.95 (s, 2H, -Ph2H); 3.93 (t, 2H, -OCH2- R ether);
4-Iod otr im eth ylsilyleth yn ylben zen e (11). Compound 10
(5 g) was taken up in freshly distilled methyl iodide (10 mL).
The solution was degassed and placed under nitrogen, and the
tube, sealed (th ick w a lled tu be; ta k e ca r e to th e over -
J . Org. Chem, Vol. 68, No. 21, 2003 8035