(E)-5-[3-Cyano-2-(dicyano­methyl­ene)-1-oxaspiro­[4.5]dec-3-en-4-yl]-3-(1-methyl-1,4-dihydro­pyridin-4-yl­idene)pent-4-en-1-yl 3,5-bis­(benz­yloxy)benzoate

In the title compound, C₄₅H₄₀N₄O₅, the cyclo­hexane entity on the (3-cyano-2,5-dihydro­furan-2-yl­idene)propane­dinitrile group, which replaces the usual dimethyl substituents, has not perturbed the delocalization geometry significantly. Weak inter­molecular inter­actions, viz. C—H...N(cyano), C—H...O(ether), C—H...π and π–π [between the aromatic rings with the shortest centroid–centroid distance of 3.603 (3) Å], consolidate the crystal packing, which exhibits voids of 57 ų.

2-[4-(2-{5-tert-Butyl-2-chloro-3-[2-(3-pentyl-1,3-benzothia­zol-2-yl­idene)ethyl­idene]cyclo­hex-1-en­yl}ethen­yl)-3-cyano-5,5-dimethyl­furan-2-yl­idene]malono­nitrile

In the title mol­ecule, C₃₆H₃₉ClN₄OS, the non-aromatic part of the cyclo­hex-1-enyl ring and the attached tert-butyl group are disordered over two conformations with occupancy ratios of 0.52 (3):0.48 (3) and 0.53 (3):0.47 (3), respectively. The polyene chain single- and double-bond dimensions contrast with a closely related compound [Bouit et al. (2007). Chem. Mater. 19, 5325–5335] with an approximate 19° twist between donor and acceptor ends of the mol­ecule, related to the additional intra­molecular C—H...S inter­action. In the title compound, the mol­ecules pack into dimeric units about centres of symmetry utilizing weak C—H...N(cyano) and C—H...O attractive inter­actions, building both chain and ring motifs about the centres [R₂²(8) and R₂²(9)]. Adjacent dimeric sets then form a herringbone configuration.

Bis(2-carb­oxy-N-{[1-(2-hy­droxy­eth­yl)-3,3-dimethyl­indolin-2-yl­idene]methyl­imino}­anilinium) sulfate monohydrate

The asymmetric unit of the title compound, 2C₂₀H₂₂N₃O₃⁺·SO₄²⁻·H₂O, contains four cations, two sulfate anions and two lattice water mol­ecules. One of the four cations shows a different conformation of the hy­droxy­ethyl group; the remaining three are all essentially superimposable. Two cations exhibit two-site orientational disorder [ratios = 0.524 (5):0.476 (5) and 0.616 (6):0.384 (6)] of the last two atoms of their hy­droxy­ethyl groups, and one water mol­ecule is disordered over two positions in a 0.634 (13):0.366 (13) ratio. Each imine H atom is intra­molecularly in contact with the adjacent carboxyl O atom, forming an S(6) motif, while all the carb­oxy­lic acid H atoms are hydrogen bonded to O atoms of the sulfate anions. Other notable hydrogen-bond inter­actions involve (methyl­ene, phenyl and imine chain) C—H...O (sulfate and carbox­yl) and O—H...O(water) contacts, making up a comprehensive three-dimensional network involving D₂²(n), with n = 4–6 and 15–16, and C₂²(17) classical hydrogen-bond motifs. The crystal investigated was twinned by pseudomerohedry with a twin component ratio of 0.4745 (12):0.5255 (12).

4-Methyl-5-(4-nitro­benzyl­idene)-2-oxo-2,5-di­hydro-1H-pyrrole-3-carbo­nitrile

Mol­ecules of the potential non-linear optical title compound, C₁₃H₉N₃O₃, form dimeric stacks of mol­ecules along the a axis cross-linked around inversion centers by N—H...O hydrogen bonds and weak (phen­yl)C—H...O inter­molecular inter­actions, forming a `collaboration' of R₂²(8) and R₂²(16) ring motifs. The mol­ecules are then further linked by weak C—H...O and C—H...N inter­actions into sheets parallel to (121).

1-(4-{[(1,3,3-Tri­methyl­indolin-2-yl­idene)meth­yl]diazen­yl}phen­yl)ethanone

The title compound, C₂₀H₂₁N₃O, has crystallographic mirror symmetry with all non-H atoms apart from the methyl C atom of the CMe₂ group lying on the mirror plane. Mol­ecules are linked into planar sheets parallel to (010) by phen­yl–azo C—H...N and phen­yl–ethanone C—H...O inter­actions. Methyl C—H...π inter­actions provide crosslinking between the planes.