title: A low-temperature polymorph of m-quinquephenyl.
abstract: A low-temperature polymorph of 1,1':3',1'':3'',1''':3''',1''''-quinquephenyl (m-quinquephenyl), C(30)H(22), crystallizes in the space group P2(1)/c with two molecules in the asymmetric unit. The crystal is a three-component nonmerohedral twin. A previously reported room-temperature polymorph [Rabideau, Sygula, Dhar & Fronczek (1993). Chem. Commun. pp. 1795-1797] also crystallizes with two molecules in the asymmetric unit in the space group P-1. The unit-cell volume for the low-temperature polymorph is 4120.5 (4) Å(3), almost twice that of the room-temperature polymorph which is 2102.3 (6) Å(3). The molecules in both structures adopt a U-shaped conformation with similar geometric parameters. The structural packing is similar in both compounds, with the molecules lying in layers which stack perpendicular to the longest unit-cell axis. The molecules pack alternately in the layers and in the stacked columns. In both polymorphs, the only interactions between the molecules which can stabilize the packing are very weak C-H...π interactions.
authors.affiliation: REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal.
authors.forename: Ligia R
authors.initials: LR
authors.lastname: Gomes
authors.forename: R Alan
authors.initials: RA
authors.lastname: Howie
authors.forename: John Nicolson
authors.initials: JN
authors.lastname: Low
authors.forename: Ana S M C
authors.initials: AS
authors.lastname: Rodrigues
authors.forename: Luís M N B F
authors.initials: LM
authors.lastname: Santos