d 7.39 (s 4H, C6H4); 0.26 (s, 18H, CH3). 13C NMR: d 132.1,
123.5 (Ar); 104.9, 96.7, (–CRC–); 0.3 (Si(CH3)3). MS (EI):
m/z (%) 270 (51) [M]1; 255 (100) [M ꢀ CH3]1.
Experimental
General conditions
Reactions involving lithium reagents were carried out under a
dry nitrogen atmosphere using standard Schlenk techniques.
Benzoquinone, naphthoquinone and anthraquinone, phenyl-
acetylene (Aldrich), trimethylsilylacetylene (Fluorochem) and
n-butyl lithium (1.6 M in hexanes, Acros) were purchased and,
with the exception of napthoquinone which was purified by
chromatography on alumina (dichloromethane) prior to use,
were used as received. Solvents were dried and deoxygenated
using an Innovative Technologies Inc. Solvent Purification
System. The compound 4-nonyloxyphenylacetylene was pre-
pared by modification of the literature methods.35 IR spectra
were recorded on an Nicolet Avatar spectrometer from nujol
mulls supported between NaCl plates. NMR spectra were
recorded from CDCl3 solutions on a Bruker Avance 400
spectrometer, and referenced against solvent resonances. Mass
spectra were recorded on Autospec EI and Micromass Quattro
II spectrometers. UV-Vis absorption spectra were recorded on
an ATI Unicam UV-2 spectrophotometer. Steady-state and
time-correlated fluorescence measurements were performed at
room temperature in dilute solutions, with an absorbance
of o0.1, using a Horiba-Jobin-Yvon Fluorolog 322 Tau3
spectrofluorimeter, using conventional 901 geometry. Fluores-
cence quantum yields were determined at room temperature,
relative to double matched standards (quinine sulfate in 0.1 M
H2SO4 and 2,20-(1,4-phenylene)bis(5-phenyloxazole) in cyclo-
hexane).36 Fluorescence lifetimes were recorded operating in
the phase-modulation mode. The phase shift and modulation
were recorded over the frequency range 1–300 MHz, and the
data fitted using the Jobin-Yvon software package. A Perkin
Acknowledgements
We thank One NorthEast for financial support through the
Nanomaterials UIC programme, the EPSRC for additional
funding support and Mr W. D. Carswell for assistance in
obtaining the DSC data.
References
1
2
U. H. F. Bunz, Chem. Rev., 2000, 100, 1605.
P. F. H. Schwab, M. D. Levin and J. Michl, Chem. Rev., 1999,
99, 1863.
3
(a) T. Tanaka, C. Sekine, T. Ashida, M. Ishitobi, N. Konya, M.
Minai and K. Fujisawa, Mol. Cryst. Liq. Cryst., 2000, 346, 209;
(b) T. M. Long and T. M. Swager, J. Mater. Chem., 2002, 12,
3407; (c) C. Y. Dai, P. Nguyen, T. B. Marder, A. J. Scott, W.
Clegg and C. Viney, Chem. Commun., 1999, 2493; (d) A. R. A.
Palmans, M. Eglin, A. Montali, C. Weder and P. Smith, Chem.
Mater., 2000, 12, 472; (e) T. Miteva, L. Palmer, L. Kloppenburg,
D. Neher and U. H. F. Bunz, Macromolecules, 2000, 33, 652; (f)
S. Hoger, V. Enkelmann, K. Bonrad and C. Tschierske, Angew.
¨
Chem., Int. Ed., 2000, 39, 2268; (g) M. E. Neubert, S. S. Keast, J.
M. Kim, K. J. Miller, R. M. Murray, A. G. Norton, R. A.
Shenoy, M. E. Walsh and R. G. Petschek, Liq. Cryst., 2004, 31,
175; (h) G. W. Skelton, D. Dong, R. P. Tuffin and S. M. Kelly, J.
Mater. Chem., 2003, 13, 450; (i) R. Gimenez, M. Pinol and J. L.
´
Serrano, Chem. Mater., 2004, 16, 1377; (j) G. J. Cross, A. J. Seed,
K. J. Toyne, J. W. Goodby, M. Hird and M. C. Artal, J. Mater.
Chem., 2000, 10, 1555; (k) J. Malthete, M. Leclercq, M. Dvo-
laitzky, J. Gabard, J. Billard, V. Pontikis and J. Jacques, Mol.
Cryst. Liq. Cryst., 1973, 23, 233.
Elmer Pyris 1 DSC operating at a heating rate of 10 1C minꢀ1
,
4
5
¨
(a) S. Hoger, Chem. Eur. J., 2004, 10, 1320; (b) L. Arnt and G. N.
Tew, Macromolecules, 2004, 37, 1283; (c) D. H. Zhao and J. S.
Moore, Chem. Commun., 2003, 807.
(a) S. Anderson, Chem. Eur. J., 2001, 7, 4706; (b) E. Arias-Marin,
J. C. Arnault, D. Guillon, T. Maillou, J. Le Moigne, B. Geffroy
and J. M. Nunzi, Langmuir, 2000, 16, 4309; (c) U. H. F. Bunz,
Acc. Chem. Res., 2001, 34, 998.
and fitted with a Cryofill cooling system was used to record the
thermal behaviour of the sample and an Olympus BX51
microscope fitted with a Linkam THMS 600 hotstage and a
Linkam TMS 94 temperature controller was used to examine
the phase behaviour of the materials. Melting points were
obtained using the same apparatus.
6
7
J. M. Seminario, A. G. Zacarias and J. M. Tour, J. Am. Chem.
Soc., 1998, 120, 3970.
(a) A. Beeby, K. S. Findlay, P. J. Low, T. B. Marder, P.
Matousek, A. W. Parker, S. R. Rutter and M. Towrie, Chem.
Commun., 2003, 2406; (b) A. Beeby, K. Findlay, P. J. Low and T.
B. Marder, J. Am. Chem. Soc., 2002, 124, 8280; (c) G. Brizius, K.
Billingsley, M. D. Smith and U. H. F. Bunz, Org. Lett., 2003, 5,
3951; (d) M. I. Sluch, G. Godt, U. H. F. Bunz and M. A. Berg, J.
Am. Chem. Soc., 2001, 123, 6447; (e) M. Levitus, K. Schmieder,
H. Ricks, K. Shimizu, U. H. F. Bunz and M. A. Garcia-Garibay,
J. Am. Chem. Soc., 2002, 124, 8181.
Syntheses
A representative synthesis of the diols: preparation of 1,4-
bis[(trimethylsilyl)ethynyl]-2,5-cyclohexadiene-1,4-diol (4a). To
trimethylsilylacetylene (7.82 mL, 5.44 g, 54.4 mmol) in THF
(50 mL) at ꢀ70 1C, n-butyllithium (33 mL, 53 mmol) was
added slowly while stirring, and the reaction mixture was then
allowed to warm to room temperature. The reaction mixture
was then cooled to ꢀ70 1C and a solution of 1,4-benzoquinone
(3.00 g, 27.7 mmol) in THF (50 mL) was added dropwise. The
solution was then allowed to warm slowly to room temperature
and stirred overnight. The reaction mixture was treated with a
saturated solution of ammonium chloride and extracted with
ethyl acetate. The organic solvents were removed under re-
duced pressure and the product was isolated following column
chromatography on silica gel with a CH2Cl2/EtOAc gradient.
8
(a) J. M. Tour, Acc. Chem. Res., 2000, 33, 791; (b) J. M.
Seminario, P. A. Derosa and J. L. Bastos, J. Am. Chem. Soc.,
2002, 124, 10266; (c) Y. Karzazi, J. Cornil and J. L. Bredas,
´
Nanotechnology, 2003, 14, 165; (d) N. Robertson and C. A.
McGowan, Chem. Soc. Rev., 2003, 32, 96; (e) A. M. Rawlett,
T. J. Hopson, I. Amlani, R. Zhang, J. Tresek, L. A. Nagahara, R.
K. Tsui and H. Goronkin, Nanotechnology, 2004, 14, 377; (f) G.
K. Ramachandran, T. J. Hopson, A. M. Rawlett, L. A. Naga-
hara, A. Primak and S. M. Lindsay, Science, 2003, 300, 1413.
For leading references see: (a) M. S. Khan, M. R. A. Al-
Mandhary, M. K. Al-Suti, F. R. Al-Battashi, S. Al-Saadi, B.
Ahrens, J. K. Bjernemose, M. F. Mahon, P. R. Raithby, M.
9
1
Yield 95%. H NMR: d 6.02 (s, 4H, C6H4); 2.34 (s, 2H, OH);
0.15 (s, 18H, CH3). 13C NMR: d 129.7 (CH) 104.5/90.1
(–CRC–), 61.2 (C(OH)), ꢀ0.29 (Si(CH3)3). IR: n(OH) 3314;
n(CRC) 2184 cmꢀ1. MS (EI): m/z (%) 304 (38) [M]1; 286 (3)
[M ꢀ H2O]1; 255 (100) [M ꢀ CH3 ꢀ 2H2O]1.
Younus, N. Chawdhury, A. Kohler, E. A. Marseglia, E. Tedesco,
¨
N. Feeder and S. J. Teat, Dalton Trans., 2004, 2377; (b) F. Paul
and C. Lapinte, Coord. Chem. Rev., 1998, 180, 431; (c) A.
Harriman and R. Zeissel, Chem. Commun., 1996, 1707; (d) F.
Barigelletti and L. Flamigni, Chem. Soc. Rev., 2000, 29, 1; (e) P.
J. Low, R. L. Roberts, R. L. Cordiner and F. Hartl, J. Solid State
Electrochem., 2005, in press; (f) M. S. Khan, A. K. Kakkar, N. J.
Long, J. Lewis, P. Raithby, P. Nguyen, T. B. Marder, F. Witt-
man and R. H. Friend, J. Mater. Chem., 1994, 4, 1227.
Representative reduction procedure: preparation of 1,4-bis
[(trimethylsilyl)ethynyl]benzene (4b). Compound 4a (7.58 g,
24.9 mmol) was dissolved in absolute EtOH (30 mL) and
added dropwise to a solution of SnCl2 ꢁ 2H2O (11.23 g, 49.8
mmol) in 50% acetic acid (30 mL) at 60 1C (10 min) and the
precipitate formed was collected by filtration and washed with
water and dried to afford 4b (3.81 g, 14.1 mol, 57%). 1H NMR:
10 (a) A. Orita, F. Ye, A. Doumoto and J. Otera, Chem. Lett., 2003,
32, 104; (b) F. Ye, A. Orita, A. Doumoto and J. Otera, Tetra-
hedron, 2003, 59, 5635; (c) K. Weiss, A. Michel, E. M. Auth,
U. H. F. Bunz, T. Mangel and K. Mullen, Angew. Chem., Int.
¨
Ed. Engl., 1997, 36, 506; (d) D. M. Bowles, G. J. Palmer,
N e w J . C h e m . , 2 0 0 5 , 2 9 , 9 7 2 – 9 7 6
975