title: A new monoclinic polymorph of 1,1'-bis-(di-phenyl-thio-phosphor-yl)ferrocene.
abstract: The title compound, [Fe(C17H14PS)2], is a second monoclinic polymorph (P21/c, with Z' = 1) of the previously reported monoclinic (C2/c, with Z' = 1/2) form [Fang et al. (1995 ▸). Polyhedron, 14, 2403-2409]. In the new form, the S atoms lie to the same side of the mol-ecule with the pseudo S-P⋯P-S torsion angle being -53.09 (3)°. By contrast to this almost syn disposition, in the C2/c polymorph, the Fe atom lies on a centre of inversion so that the S atoms are strictly anti, with a pseudo-S-P⋯P-S torsion angle of 180°. The significant difference in mol-ecular conformation between the two forms does not result in major perturbations in the P=S bond lengths nor in the distorted tetra-hedral geometries about the P atoms. The crystal packing of the new monoclinic polymorph features weak Cp-C-H⋯π(phen-yl) inter-actions consolidating linear supra-molecular chains along the a axis. These pack with no directional inter-actions between them.
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Yee Seng
authors.initials: YS
authors.lastname: Tan
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Chien Ing
authors.initials: CI
authors.lastname: Yeo
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink
keywords: conformation; crystals structure; ferrocene derivative; polymorph