Aqua­(2,2′-bipyridine-κ²N,N′)(L-malato-κ³O,O′,O′′)copper(II)

In the title complex, [Cu(C₄H₄O₅)(C₁₀H₈N₂)(H₂O)], the chiral L-malate group, which acts as a tridentate ligand, the bidentate 2,2′-bipyridine ligand and the water mol­ecule provide an octa­hedral coordination of the Cu^II atom with strong Jahn–Teller distortion. Inter­molecular O—H...O hydrogen bonds stabilize the crystal packing.

Dimethyl naphthalene-1,8-dicarboxyl­ate

In the title compound, C₁₄H₁₂O₄, the two ester groups are twisted away from the attached rings by 43.9 (2) and 41.8 (2)°. The crystal packing is stabilized by C—H...O hydrogen bonds.

Diethyl­enetriammonium oxonium naphthalene-1,6-disulfonate 3.5-hydrate

The title complex, C₄H₁₆N₃³⁺·H₃O⁺·2C₁₀H₆O₆S₂²⁻·3.5H₂O, comprises one diethyl­enetriammonium trication, one oxonium cation, two naphthalene-1,6-disulfonate dianions and three-and-a-half water mol­ecules. The oxonium cation donates a proton to each of three acceptors, forming strong hydrogen bonds, O—H...O [2.476 (4), 2.473 (4) and 2.503 (4) Å]. O—H...O and N—H...O hydrogen bonds link the title complex into layers parallel to the (010) plane.