The crystal structure of the π-molecular complex of anthracene with pyromellitic dianhydride at –120°C

An analysis of Ci4Hl0.Cl0H206 has been made for a crystal at -120 (2)°C: a = 7.2812 (6), b = 10.7684 (7), c = 7.1246 (7) A,a = 117.516 (7), fl = 111.513 (8), y = 97.437 (8) °, Z = 1. The refinement with the full data set (3769 observed reflections, sin 0/2 _< 0.910 A -1, 2 = 0.71069 A) converged with R = 0-046 and R,~ = 0.062. A comparison of refinements with truncated data sets: 0.478 < sin 0/2 < 0.91 A -~ and sin 0/2 _< 0.610 A -~ is presented. The crystal packing is examined in detail in an effort to determine which structural properties arise therefrom and thus not from charge-transfer' effects. Comparison with crystal structures for non-complexed anthracene and pyromellitic dianhydride indicate that the lowtemperature crystal structure determination has not revealed detectable changes in bonding geometry due to formation of the complex.