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J. G. Rodrıguez et al. / Tetrahedron 59 (2003) 1021–1032
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8.21 (d, 2H, J¼6.8 Hz, H-2 Py); 7.90 (d, 1H, J¼16.3 Hz,
PhCHv); 7.89 (d, 2H, J¼8.4 Hz, H-3 Ph); 7.55 (d, 2H,
J¼8.4 Hz, H-2 Ph); 7.50 (d, 1H, J¼16.3 Hz, PyCHv); 4.38
(s, 3H, N–CH3). UV–visible (EtOH), lmax (nm): 223
(80225); 284 (27500); 355 (1260). Calcd for C14H13NI2: C,
37.44; H, 2.92; N, 3.12. Found: C, 37.18; H, 3.20; N, 2.94%.
Dimethylated salt (Z,Z)-15. IR (KBr): 1600, 1500 and 1450
(CvC, conj.); 1320 (N–CH3); 1180 (Pyþ–CH3); 975 and
880 (Py sust.); 840 and 830 (p-disubst.). 1H NMR (DMSO):
8.78 (d, 4H, J¼6.6 Hz, H-2 and H-6, Py); 7.83 (d, 4H,
J¼6.6 Hz, H-3 and H-5, Py); 7.57 (d, 4H, J¼8.3 Hz, H-2
and H-6, Ph); 7.34 (d, 4H, J¼8.3 Hz, H-3 and H-5, Ph); 7.23
(d, 2H, J¼12.3 Hz, Py–CHvCH, Z); 6.89 (d, 2H,
J¼12.3 Hz, Py–CHvCH, Z); 4.28 (s, 6H, CH3). MS
(FABþ): 438 (Mþ, 43); 423 (35); 219 (22). UV–visible
(CH2Cl2): 236 (6800); 292 (5080); 396 (6520 l mol21
cm21). Calcd for C33H26N2I2: C, 56.27; H, 3.72; N, 3.98.
Found: C, 56.09; H, 3.60; N, 3.78%.
Di-{4-[p-(2-ethenylphenyl)]pyridinium iodide}, (E,E)-13. A
solution of dichlorobis(triphenyl)phosphine nickel (II)
(245.1 mg, 0.377 mmol) in anhydrous THF (25 ml), tetra-
butylammonium iodide (139.4 mg, 0.377 mmol) and zinc
powder (36.6 mg, 0.56 mmol), under argon atmosphere,
was stirred for 30 min. The solution turns to red colour and
then a solution of (E)-4 (170 mg, 0.377 mmol) in anhydrous
THF (10 ml) was added. The mixture was stirred overnight
at room temperature. Finally, dichloromethane (25 ml) was
added, and the catalyst was filtered. Solvent was removed,
and compound 13 was obtained as a yellow solid, 82 mg
(68%). IR (KBr): 1624 (CvN); 1597 and 1516 (CvC);
1184 (þN–CH3); 997 (E-isomer); 838 (p-subst. ArH); 724
(Z-isomer). 1H NMR (MeOD): 8.86 (d, 4H, J¼6.7 Hz, H-3
Py, E-isomer); 8.82 (d, 4H, J¼6.7 Hz, H-3 Py, Z-isomer);
8.30 (d, 4H, J¼6.7 Hz, H-2 Py, E-isomer); 8.17 (d, 4H,
J¼6.7 Hz, H-2 Py, Z-isomer); 8.10 (d, 2H, J¼16.0 Hz, Ph–
CHv, E-isomer); 8.00–7.72 (m, 18H, Biph and Py–CHv
(E-isomer)); 7.31 (d, 2H, J¼11.6 Hz, Z-isomer); 7.09 (d,
2H, J¼11.6 Hz, Z-isomer); 4.41 (s, 6H, þN–CH3, E-
isomer); 4.37 (s, 6H, þN–CH3, Z-isomer). UV–visible
(EtOH), lmax (nm): 196 (1¼71460); 223 (1¼ 22085); 333
(1¼16500). Calcd for C28H26N2I2: C, 52.19; H, 4.07; N,
4.35. Found: C, 52.44; H, 3.93; N, 4.57%.
3.3.4. Charge–transfer complex between (Z,Z)-15 and
N,N,N0,N0-tetramethyl-p-phenylendiamine (TMPD), 16.
A hot solution of TMPD (100 mg, 0.61 mmol) in hot
acetonitrile (25 ml) was added to a nearly boiling solution of
(Z,Z)-15 (132 mg, 0.30 mmol) in acetonitrile (50 ml). The
mixture was stirred at reflux temperature for 2 h. The resulting
green solution was allowed to cool and then to evaporate
slowly to provide the complex 16 as a green solid. The solid
was continuously extracted with hexane in a soxhlet giving a
green solid with metallic bright. A 1:1 stoichiometry between
the components was deduced from the spectroscopic analysis.
IR (KBr): 1610, 1590, 1540, 1510 and 1460 (CvC, conj.);
1340 (N–CH3); 1185 and 1170 (Pyþ–CH3); 980, 950 and 880
(subst. Py);840(p-disubst.). 1H NMR (DMSO): 8.90(brs, 2H,
H-2 and H-6, Py); 8.25 (br s, 2H, H-2 and H-6, Py, complexed
ring); 8.05 (br s, 2H, H-3 and H-5, Py); 7.9–7.4 (m, 10H, Ph
and H-3 and H-5, Py, complexed ring); 7.36 (br d, 1H, Py–
CHvCH); 7.22 (br d, 1H, Py–CHvCH); 6.90 (br d, 1H, Py–
CHvCH, complexed ring); 6.72 (br d, 1H, Py–CHvCH,
complexed ring). UV–visible (CH2Cl2): 230 (6740), 265
(4400), 315 (5080), 401 (6600), 533 (660) and 639 nm
(905 l mol21 cm21). DSC: .1258C, broad endothermic peak
(decomposed). Calcd for C39H42N4I2: C, 57.08; H, 5.16; N,
6.83. Found: C, 57.16; H, 5.52; N, 6.54%.
3.3.3. Mono- and di-methylated salts, (Z,Z)-14 and (Z,Z)-
15, of (Z,Z)-1,4-di[(40-pyridylethenyl)-400-phenyl]-buta-
1,3-diyne, (Z,Z)-5. To a solution of (Z,Z)-5 (100 mg,
0.24 mmol) in ethanol (25 ml) and ethyl acetate (5 ml),
was added iodomethane (0.06 ml, 0.96 mmol). The mixture
was heated at reflux temperature and stirred overnight. After
cooling, a yellow precipitate was filtered and identified as
the dimethylated salt (Z,Z)-15, 70 mg (44%), mp 2308C
(dec.). The filtered solution was evaporated yielding an
orange solid identified as the monomethylated salt (Z,Z)-14,
70 mg (53%), mp 1808C (dec.).
3.3.5. Charge–transfer complex between (Z,Z)-15 and
7,7,8,8-tetracyano-p-quinodimethane (TCNQ), 17. A hot
solution of TCNQ (35 mg, 0.17 mmol) in hot acetonitrile
(15 ml) was added to a hot solution of (Z,Z)-15 (75 mg,
0.17 mmol) in acetonitrile (70 ml). The mixture was stirred
at reflux temperature for 20 min. After cooling the green
solution was slowly evaporated at room temperature
yielding the complex as a green solid, which was
continuously extracted with hexane in a soxhlet, giving
the complex 17 as a black–green solid. A 2:1 stoichiometry
between the components was deduced by spectroscopic and
combustion analysis. 1H NMR (DMSO): 8.9 (d, 4H, H-2 and
H-6, Py); 8.25 (d, 4H, H-3 and H-5, Py); 8.08 (m, 4H,
TCNQ); 7.9–7.5 (m, 8H, Ph); 7.39 (d, 2H, J¼12.5 Hz, Py–
CHvCH); 7.08 (d, 2H, J¼12.5 Hz, Py–CHvCH); 4.30 (s,
6H, CH3). UV–visible (CH2Cl2): 239 (6800), 400 (6520),
644 (780 l mol21 cm21). DSC: .1608C, decomposed.
Calcd for C57H31N10I2: C, 61.69; H, 2.82; N, 12.62.
Found: C, 61.45; H, 2.56; N, 12.25%.
Monomethylated salt (Z,Z)-14. IR (KBr): 1610, 1500 and
1460 (CvC and CvN, conj.); 1330 (N–CH3); 1185 (Pyþ–
CH3); 980, 890 and 880 (Py sust.); 835 (p-disust.).
1H NMR (MeOD): 8.91 (d, 2H, J¼6.7 Hz, H-2 y H-6,
methylated Py); 8.46 (d, 2H, J¼6.3 Hz, H-2 and H-6, Py);
7.99 (d, 2H, J¼6.7 Hz, H-3 and H-5, methylated Py); 7.54
(d, 2H, J¼8.7 Hz, H-2 and H-6, Ph near to methylated Py);
7.49 (d, 2H, J¼8.7 Hz, H-2 and H-6, Ph); 7.39 (d, 2H,
J¼8.7 Hz, H-3 and H-5, Ph near to methylated Py); 7.40 (d,
1H, J¼12.5 Hz, Me–Pyþ –CHvCH); 7.30 (d, 2H,
J¼8.7 Hz, H-3 and H-5 Ph); (7.19 (d, 2H, J¼6.3, H-3 and
H-5, Py); 6.97 (d, 1H, J¼12.5 Hz, Me–Pyþ–CHvCH);
6.89 (d, 1H, J¼12.0 Hz, Py–CHvCH); 6.78 (d, 1H,
J¼12.0 Hz, Py–CHvCH); 4.50 (s, 3H, CH3). UV–visible
(CH2Cl2): 230 (1, 7800); 292 (1, 4800); 340 (1, 5130);
385 (1, 6000 l mol21 cm21). Calcd for C31H23N2I: C,
67.64; H, 4.21; N, 5.09. Found: C, 67.47; H, 4.56; N,
5.05%.
Acknowledgements
We are greatly indebted to CICYT of Spain for financial
support (PB97-0060).