title: Crystal structures of 2,2'-bipyridin-1-ium 1,1,3,3-tetracyano-2-ethoxyprop-2-en-1-ide and bis(2,2'-bipyridin-1-ium) 1,1,3,3-tetracyano-2-(dicyanomethylene)propane-1,3-diide.
abstract: In 2,2'-bipyridin-1-ium 1,1,3,3-tetra-cyano-2-eth-oxy-prop-2-en-1-ide, C10H9N2 (+)·C9H5N4O(-), (I), the ethyl group in the anion is disordered over two sets of atomic sites with occupancies 0.634 (9) and 0.366 (9), and the dihedral angle between the ring planes in the cation is 2.11 (7)°. The two independent C(CN)2 groups in the anion make dihedral angles of 10.60 (6) and 12.44 (4)° with the central propenide unit, and the bond distances in the anion provide evidence for extensive electronic delocalization. In bis-(2,2'-bipyridin-1-ium) 1,1,3,3-tetra-cyano-2-(di-cyano-methyl-ene)propane-1,3-diide [alternative name bis-(2,2'-bipyridin-1-ium) tris-(di-cyano-methyl-ene)methane-diide], 2C10H9N2 (+)·C10N6 (2-) (II), the dihedral angles between the ring planes in the two independent cations are 7.7 (2) and 10.92 (17)°. The anion exhibits approximate C 3 symmetry, consistent with extensive electronic delocalization, and the three independent C(CN)2 groups make dihedral angles of 23.8 (2), 27.0 (3) and 27.4 (2)° with the central plane. The ions in (I) are linked by an N-H⋯N hydrogen bond and the resulting ion pairs are linked by two independent C-H⋯N hydrogen bonds, forming a ribbon containing alternating R 4 (4)(18) and R 4 (4)(26) rings, where both ring types are centrosymmetric. The ions in (II) are linked by two independent N-H⋯N hydrogen bonds and the resulting ion triplets are linked by a C-H⋯N hydrogen bond, forming a C 2 (1)(7) chain containing anions and only one type of cation, with the other cation linked to the chain by a further C-H⋯N hydrogen bond.
authors.affiliation: Laboratoire de Chimie, Ingénierie Moléculaire et Nanostructures (LCIMN), Université Ferhat Abbas Sétif 1, Sétif 19000, Algeria ; Unité de Recherche de Chimie de l'Environnement et, Moléculaire Structurale (CHEMS), Université Constantine 1, Constantine 25000, Algeria.
authors.forename: Zouaoui
authors.initials: Z
authors.lastname: Setifi
authors.affiliation: Department of Chemistry, University of Jyväskylä, PO Box 35, FI-40014 Jyväskylä, Finland.
authors.forename: Arto
authors.initials: A
authors.lastname: Valkonen
authors.affiliation: School of Chemistry, University of the Witwatersrand, PO Wits, 2050 Johannesburg, South Africa.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Fernandes
authors.affiliation: Molecular Materials, Department of Applied Physics, School of Science, Aalto University, PO Box 15100, FI-00076 Aalto, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Nummelin
authors.affiliation: Laboratoire de Matériaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia.
authors.forename: Habib
authors.initials: H
authors.lastname: Boughzala
authors.affiliation: Laboratoire de Chimie, Ingénierie Moléculaire et Nanostructures (LCIMN), Université Ferhat Abbas Sétif 1, Sétif 19000, Algeria.
authors.forename: Fatima
authors.initials: F
authors.lastname: Setifi
authors.affiliation: School of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland.
authors.forename: Christopher
authors.initials: C
authors.lastname: Glidewell
keywords: bipyridinium cations; crystal structure; hydrogen bonding; mol­ecular conformation; polynitrile anions