(E)-2-Methyl-3-phenyl­selanyl-4-(phenyl­sulfin­yl)oct-3-en-2-ol

In the title compound, C₂₁H₂₆O₂SSe, the S atom adopts a pyramidal geometry (bond-angle sum = 304°) and the n-butyl chain shows an extended conformation. An intra­molecular C—H...O hydrogen bond closes an S(8) ring. In the crystal, inversion dimers are formed with molecules linked by pairs of O—H...O=S hydrogen bonds, generating R₂²(14) loops. Weak C—H...O inter­actions also occur.

Crystal structure of 4,4′-(ethene-1,2-di­yl)dipyridinium bis­(3-carb­oxy­benzene­sulfonate)

In the title mol­ecular salt, C₁₂H₁₂N₂²⁺·2C₇H₅O₅S⁻, the complete dication is generated by crystallographic inversion symmetry. In the anion, the sulfonic acid group is deprotonated and the dihedral angle between the planes of the carb­oxy­lic acid group and the benzene ring is 12.41 (11)°. In the crystal, the anions are linked into inversion dimers by pairs of O—H...O hydrogen bonds, which generate R₂²(16) loops. The dications link the anion dimers into [10-2] chains via N—H...O hydrogen bonds.