We have synthesized 1,4,7,10-tetraisoalkyltetracenes from a 2,6-naphthodiyne precursor and 2,5-diisoalkylfurans as the starting materials (isoalkyl: isopropyl, isobutyl, and isopentyl). The tetracene molecules exhibited crystallochromy: The solid-state colors of the isopropyl, isobutyl, and isopentyl derivatives were yellow, red, and orange-yellow, respectively. In contrast, there were no marked differences in the optical properties of these compounds in solution. The isopropyl derivative exhibited the highest fluorescence quantum yield in

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Solid-state packing effects play an important role in the performance of electronic and photonic materials. 1 We recently found that the introduction of alkyl side chains onto the anthracene nucleus at the 1-, 4-, 5-, and 8-positions brought about drastic changes in both the packing and solid-state fluorescence properties. 2 The length of the alkyl side chains affected not only the packing arrangement and the solid-state fluorescence, but also the molecular geometry. Thus, the molecular structures were classified into plane (the ethyl derivative), semi-chair (the propyl derivative), and chair (the hexyl derivative) forms. To investigate the effects of the alkyl side-chain length systematically, investigations on the butyl and pentyl derivatives remained. Herein we report on an X-ray analysis of the pentyl derivative, 1,4,5,8-tetrapentylanthracene. The title compound was synthesized by our recently reported procedure using 2,5-dipentylfuran, 1,2,4,5-tetrabromobenzene, and n-BuLi. 2 Colorless crystals suitable for X-ray analysis were obtained by slow evaporation of a hexane solution at room temperature. All measurements were made on a Rigaku/MSC Mercury CCD diffractometer with Mo-Ka (l = 0.71073 Å) at 223 K. A structure determination was carried out using the program SIR2004. 3 All of the non-hydrogen atoms were refined anisotropically by full-matrix least-squares on F 2 using SHELXL97. 4 H atoms were placed at calculated positions, with C-H distances of 0.94-0.98 Å, and treated as riding atoms, with Uiso(H) = 1.2 Ueq(C) for Csp 2 and CH2, and Uiso(H) = 1.5 Ueq(C) for CH3. All calculations were performed using the WinGX

Tetracenes. -The regioisomeric mixtures (III)/(IV) are synthesized via Diels-Alder reaction. The color of the mixtures changes before and after the recrystallization from Et2O, suggesting a change in the distribution of anti/syn regioisomers. -(KITAMURA*, C.; KANO, H.; TSUKUDA, H.; KAWASE, T.; KOBAYASHI, T.; NAITO, H.; Heterocycles 83 (2011) 7, 1621-1629, http://dx.doi.org/10.3987/com-11-12191 ; Dep. Mater. Sci. Chem., Univ. Hyogo, Himeji, Hyogo 671, Japan; Eng.) -C. Gebhardt 46-082

The mol­ecule of the title compound, C30H42, occupies a special position on an inversion center. The four butyl side chains have all-trans planar conformations, and the alkyl planes are nearly orthogonal to the anthracene plane [C—C—C—C torsion angles of 79.6 (2) and 78.2 (2)°]. The overall mol­ecule has a stair-like shape with the n-butyl groups at the 1 and 8 positions extending towards the same side of the anthracene plane. In the crystal structure, mol­ecules adopt a slipped–parallel arrangement without π–π stacking.