STUDIES ON AROMATIC TRICHROMOPHORE SYSTEMS INCORPORATING ANTHRACENE MOIETIES .2. CRYSTAL-STRUCTURES OF 2-(9-ANTHRYL)-1-(9-ANTHRYLMETHYL)ETHYL 2-(9-PHENANTHRYL)-ETHYL SUCCINATE (A(2)PHEN) AND 2-(9-ANTHRYL)-1-(9-ANTHRYLMETHYL)ETHYL METHYL SUCCINATE (A(2)SC) AND THEIR FLUORESCENCE IN THE SOLID-STATE

The structures of 2-(9-anthryl)-1-(9-anthrylmethyl)ethyl 2-(9-phenanth ryl)ethyl succinate (A2PHEN) and 2-(9-anthryl)-1-(9-anthrylmethyl)ethy l methyl succinate (A2sc) have been determined by X-ray diffraction, a nd the molecular fluorescence of the crystals has been established. Th e two crystals are monoclinic. A2PHEN: C2/c, a 39.47(1), b 9.718(2), c 19.924(8) angstrom; beta 97.81(3)-degrees; R 0.036 for 2903 unique re flections. A2SC: P2(1)/c, a 16.248(2), b 10.325(2), c 18.052(2) angstr om. Beta 114.20(3)-degrees; R 0-044 for 2586 unique reflections. For b oth structures, the bisanthracene moiety and a large part of the ester chain show similar conformations. The crystal cohesion is due to inte rmolecular pi overlapping between one of the anthracene components of the bichromophore moiety and to numerous van der Waals interactions. N o intramolecular interactions between the phenanthrene and the anthrac ene moieties are observed in A2PHEN. The fluorescence emissions Of A2P HEN and A2sc axe of excimer type, and correlate well with the intermol ecular interactions between the anthracene rings.