title: Crystal structure of (E)-2-(4-chloro-benzyl-idene)-3,4-di-hydro-naphthalen-1(2H)-one: a second monoclinic polymorph.
abstract: The title compound, C17H13ClO, is the second monoclinic polymorph to crystallize in the space group P21/c. The first polymorph crystallized with two independent mol-ecules in the asymmetric unit [Bolognesi et al. (1975 ▸). Acta Cryst. A31, S119; Z' = 2; no atomic coordinates available], whereas the title compound has Z' = 1. In the title polymorph, the dihedral angle between the plane of the benzene ring of the tetra-lone moiety and that of the 4-chloro-benzyl ring is 52.21 (11)°. The cyclo-hex-2-en-1-one ring of the tetra-lone moiety has a screw-boat conformation. In the crystal, mol-ecules are liked by pairs of C-H⋯π inter-actions forming inversion dimers. There are no other significant inter-molecular inter-actions present.
authors.affiliation: Department of Chemistry, Mirpur University of Science and Technology (MUST), Mirpur, Azad Jammu and Kashmir, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Haroon
authors.affiliation: Department of Chemistry, Mirpur University of Science and Technology (MUST), Mirpur, Azad Jammu and Kashmir, Pakistan.
authors.forename: Tashfeen
authors.initials: T
authors.lastname: Akhtar
authors.affiliation: Department of Physics, University of Sargodha, Sargodha, Punjab, Pakistan.
authors.forename: Muhammad Nawaz
authors.initials: MN
authors.lastname: Tahir
keywords: C—H⋯π inter­actions; crystal structure; α-tetra­lone