1-Methyl-4-[(E)-2-(2-thien­yl)­ethen­yl]­pyridinium 4-methyl­benzene­sulfonate1

In the title compound, C12H12NS+·C7H7O3S−, the cation exists in an E configuration with respect to the ethenyl C=C bond. The cation is essentially planar with a dihedral angle of 1.94 (10)° between the pyridinium and thio­phene rings. The benzene ring of the anion makes dihedral angles of 75.23 (10) and 76.83 (10)°, respectively, with the pyridinium and thio­phene rings. In the crystal structure, cations and anions form alternate layers parallel to the bc plane. Within each layer, both cations and anions are arranged into chains directed along the b axis. The cation chain and the anion chain are inter­connected by weak C—H⋯O inter­actions into a three-dimensional network. The crystal structure is further stabilized by C—H⋯π inter­actions

1-Methyl-2-[(E)-2,4,5-trimeth­oxy­styr­yl]pyridinium 4-meth­oxy­benzene­sulfonate monohydrate

In the title compound, C17H20NO3 +·C7H7O4S−·H2O, the cation exists in an E configuration with respect to the C=C bond and is twisted with a dihedral angle of 17.81 (8)° between the pyridinium and benzene rings. The benzene ring of the anion is almost parallel to the pyridinium ring [dihedral angle = 3.45 (9)°], whereas it is inclined to the benzene ring of the cation [dihedral angle = 17.62 (8)°]. The crystal structure is stabilized by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions which link the cations, anions and water mol­ecules into chains along the a axis. π–π inter­actions with centroid–centroid distances of 3.7751 (9) and 3.7920 (11) Å are also observed

4-Bromo-N-(4-meth­oxy-2-nitro­phen­yl)benzamide

In the title compound, C14H11BrN2O4, the amide segment makes dihedral angles of 23.4 (2) and 20.5 (2)° with the benzene rings, while the dihedral angle between the bezene rings is 2.90 (8)°. The nitro and meth­oxy groups are almost coplanar with their bound benzene ring, with the r.m.s. deviation for the 11 non-H atoms being 0.0265 (1) Å. An intra­molecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked into [2-10] chains by weak C—H⋯O and C—H⋯Br inter­actions, which form an R 2 2(8) motif between pairs of mol­ecules in the chain. A Br⋯O [3.2018 (12) Å] short contact also occurs

1-Methyl-2-[(E)-2-(2-thien­yl)ethen­yl]quinolinium 4-bromo­benzene­sulfonate

In the title compound, C16H14NS+·C6H4BrO3S−, the cation exists in an E configuration and is essentially planar, the dihedral angle between the quinolinium and thio­phene rings being 3.45 (9)°. The anion is inclined to the cation with dihedral angles of 75.43 (8) and 72.03 (11)°, respectively between the benzene ring and the quinolinium and thio­phene rings. In the crystal, the cations and anions are arranged individually into separate chains along the c axis. The cation chains are stacked in an anti­parallel manner along the a axis by π⋯π inter­actions with centroid–centroid distances of 3.7257 (13) and 3.7262 (14) Å. Weak C—H⋯O and C—H⋯π inter­actions link the cations and anions into a three-dimensional network. Short Br⋯S [3.7224 (5) Å] and Br⋯O [3.4267 (16) Å] contacts are also observed

2,2′-[2,4-Bis(naphthalen-1-yl)cyclo­butane-1,3-di­yl]bis­(1-methyl­pyridinium) diiodide: thermal-induced [2 + 2] cyclo­addition reaction of a heterostilbene1

The asymmetric unit of the title compound, C36H32N2 2+·2I−, consists of one half-mol­ecule of the cation and one I− anion. The cation is located on an inversion centre. The dihedral angle between the pyridinium ring and the naphthalene ring system in the asymmetric unit is 19.01 (14)°. In the crystal, the cations and the anions are linked by C—H⋯I inter­actions into a layer parallel to the bc plane. Intra- and inter­molecular π–π inter­actions with centroid–centroid distances of 3.533 (2)–3.807 (2) Å are also observed

(1E,4E)-1,5-Bis(2,4,5-trimethoxy­phen­yl)penta-1,4-dien-3-one1

There are three mol­ecules in the asymmetric unit of the title compound, C23H26O7, in which the dihedral angles between two benzene rings are 4.34 (9), 18.11 (8) and 8.54 (8)°. The central penta-1,4-dien-3-one fragment makes dihedral angles of 3.95 (9) and 3.32 (16)° with the two adjacent benzene rings in one mol­ecule, whereas the corresponding pairs of angles in the other two mol­ecules are 10.34 (9)/17.46 (8)° and 7.87 (8)/13.33 (8)°. In the crystal, mol­ecules are linked by inter­molecular C—H⋯O and C—H⋯π weak inter­actions into a three-dimensional network. Finally, π–π inter­actions [centroid⋯centroid distances = 3.5984 (10) and 3.5545 (10) Å] are observed

(E)-4-[2-(4-Eth­oxy­phen­yl)ethen­yl]-1-methyl­pyridinium 4-bromo­benzene­sulfonate methanol hemisolvate1

In the title compound, C16H18NO+·C6H4BrO3S−·0.5CH3OH, the cation exists in the E configuration and the whole mol­ecule of the cation, except for the O atom of the eth­oxy group, is disordered with a site-occupancy ratio of 0.695 (5):0.305 (5). The cation is disordered in such a way that the ethenyl units of the major and minor components are related by 180° around the long mol­ecular axis. In the major component, the cation is almost planar, the dihedral angle between the pyridinium and benzene rings being 0.8 (3)°, whereas in the minor component, the dihedral angle between the two aromatic rings is 4.2 (6)°. In the crystal, the cations are stacked in an anti­parallel manner along the a axis, while the anions and methanol mol­ecules are linked through O—H⋯O hydrogen bonds and Br⋯O short contacts [3.0248 (13) Å] into a tape along the same direction. The three components are further linked by weak C—H⋯O, C—H⋯Br and C—H⋯π inter­actions

2-[(E)-2-(4-Ethoxy­phen­yl)ethen­yl]-1-methyl­pyridinium iodide monohydrate

In the title compound, C16H18NO+·I−·H2O, the cation is essentially planar, with a dihedral angle of 3.13 (16)° between the pyridinium and benzene rings. The mol­ecule adopts an E configuration with respect to the alkene double bond. In the crystal structure, the cations are packed in an anti-­parallel manner through π–π inter­actions between adjacent pyridinium and benzene rings along the a axis, with centroid-to-centroid distances of 3.615 (2) and 3.630 (2) Å. Water mol­ecules bind the iodide ions through O—H⋯I hydrogen bonds into layers. These layers link with the cations through weak C—H⋯O and C—H⋯I inter­actions

Bis[(E)-2-(3-hydr­oxy-4-methoxy­phen­yl)ethen­yl]-1-methyl­quinolinium tetra­iodidozincate(II) methanol solvate1

In the title compound, (C19H18NO2)2[ZnI4]·CH3OH, each cation is nearly planar and exists in an E configuration, the dihedral angles between the quinolinium systems and the benzene rings being 1.78 (10) and 5.44 (10)° for the two cations. The [ZnI4]2− anion displays a very slightly distorted tetra­hedral geometry. There are intra­molecular O—H⋯O hydrogen bonds between the hydr­oxy and meth­oxy groups in each cation which generate S(5) ring motifs. In the crystal structure, cations are linked together by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions, whereas the anions are linked to the cations through weak C—H⋯I inter­actions. The asymmetric unit also contains a methanol solvent mol­ecule which is linked to one of the cations by an O—H⋯O hydrogen bond and the anion through an O—H⋯I hydrogen bond. The crystal is further stabilized by C—H⋯π and π–π inter­actions [centroid–centroid distances 3.6054 (15) and 3.6057 (15) Å]