title: 3,3'-Dimethyl-1,1'-(methyl-enedi-p-phenyl-ene)diimidazolium bis-(hexa-fluoro-phosphate).
abstract: The title N-heterocyclic carbene compound, C(21)H(22)N(4) (2+)·2PF(6) (-), crystallizes as an inversion twin. There are two independent N-heterocyclic carbene dications (A and B) and four independent hexa-fluoro-phosphate anions in the asymmetric unit. The cations are L-shaped with the benzene rings being inclined to one another by 88.82 (16)° in cation A and 87.03 (16)° in cation B. The imidazole rings make dihedral angles of 35.7 (2) and 32.83 (18)° with the attached benzene rings in cation A, and 30.14 (19) and 31.96 (18)° in cation B. In the crystal, the cations are linked via C-H⋯F hydrogen bonds, forming a three-dimensional network. π-π inter-actions involving the benzene and imidazole rings [centroid-centroid distances = 3.602 (2) and 3.723 (2) Å] and C-H⋯π inter-actions are also present.
authors: School of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002, People's Republic of China.
authors: Kun
authors: K
authors: Huang
authors: Ping
authors: P
authors: Zhang
authors: Da-Bin
authors: DB
authors: Qin
references: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references: 18156677
references: Chem Rev. 2009 Aug;109(8):3561-98
references: 19361198
references: Acta Crystallogr Sect E Struct Rep Online. 2009 May 14;65(Pt 6):o1271-2
references: 21583134