Although oligo(ethy1ene glycols) [H[-0CH2CH2In-OH, 1 (n ); cf. Scheme I] have found widespread application as synthons for crown ether-type derivatives,l surfactants,2 ion-conducting materials: and new materials: the published synthetic methods for commercially unavailable or expensive representatives l(n) (n > 4) are hampered by (1) Huezthy, P.; Bradshaw, J. S.; Zbu, C. Y.; Izatt, R. M.; Lifson, S. Le Nest, J. F.; Gandini, A.; Armand, M. Polym. Bull. 1991, 25, 443-460. (b) Bianconi, P. A.; Lin, J.; Strzelecki, A. R. Nature 1991,349,315-317. (5) (a) Bedells, A. D.; Mobbe, R. H.; Booth, C. Makromol. Chem. 1991, 192, 2089-2098 and refs cited therein. (b) Coudert, G.; Mpaesi, M.; Guillaumet, G.; Selve, C. Synth. Commun. 1986, f6,1$&26 and refs cited therein. (c) Nakatauji, Y.; Kameda, N.; Okahara, M. Synthesis 1986, 280-281 and refs cited therein. (d) Bradshaw, J. S.; Reeder, R. A.; Thompson, M. D.; Flanders, E. D.; Carruth, R. L.; Izatt, R. M.; Christensen, J. J. J. Org. Chem. 1976, 41, 134-136. (6) (a) Ouchi, M.; Inoue, Y.; Liu, Y.; Nagamune, S.; Nakamura, S.; Wada, K.; Hakushi, T. Bull. Chem. SOC. Jpn. 1990,63,1260-1262 and refs cited therein. (b) Kyba, E. P.; Helgeson, R. C.; Madan, K.; Gokel, G. W.; Tarnowski, T. L.; Moore, 5. S.; Cram, D. J.

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In its crystal structure 2-methoxy-l,4-benzoquinone 2 is networked into a planar hexagonal pattern by intermolecular dipole-dipole-and extensive C-H.-O hydrogen bond interactions leading to a graphite-like layer packing motif.

In the solid state 2,5-di-n-alkoxy-1,4-benzoquinones 1( n ) organize into a two-dimensional layered structure with columnarly stacked 1,4-benzoquinone moieties along the a and b axis leading to improved intermolecular π-overlap. An interplay between intermolecular merocyanine-type dipole−dipole interactions, directional weak C−H···O hydrogen bond interactions and nondirectional van der Waals interactions is responsible for this packing motif. DSC of 1( n ) shows that for n = 3−19 pronounced solid−solid phase transitions are discernible. Concomitant with alkoxy chain length odd−even effects are observed. Linear relationships are found between enthalpy and entropy changes, respectively, at distinct phase transitions for 1( n ) with n ≥ 9 (n = odd) and n ≥ 10 (n = even) indicative for identical packing motifs in both series, respectively. Picnometry reveals that the densities of 1( n ) with n = odd are higher than those for n = even. As shown by single-crystal X-ray structure analyses (1(3), 1(9), and 1(10)) and wide-angle X-ray diffraction (WAXD, 1( n ), 9 ≤ n ≤ 19), this can be attributed to improved end-group packing of the alkoxy chains in the odd series.

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