In the title complex, [Sm(C7H3O4)(C7H4O4)(H2O)2]·4H2O, the coordination number of the Sm atom is nine. The pyridine‐2,6‐di­carboxyl­ate ligand chelates to the Sm atom and bridges to the neighbouring Sm atoms to form infinite chains along the c axis.

The title compound, [Ga(CH3)2(C21H17N2O)], synthesized by the reaction of tri­methyl­gallium and 4‐methyl‐2,6‐bis­(phenyl­imino­methyl)­phenol, has the Ga atom in a tetrahedral geometry; two mol­ecules form a dimer through a π–π interaction.

In the title compound, [Cu(C7H3NO4)(C4H6N2)(CH4O)], the Cu atom lies in the centre of an N2O2 square plane, and the methanol mol­ecule is apically coordinated. The coordination geometry is best described as distorted square‐pyramidal. There are intermolecular hydrogen bonds in the crystal structure, which mediate the formation of layers.

The title complex, [Cu(C5H4NO2)2], displays a trans‐O2(N‐oxide)O2 square‐planar coordination geometry for the CuII centre. In the crystal structure, the mol­ecules assemble into a three‐dimensional structure by way of intermolecular π–π interactions and weak intermolecular C—H⋯O interactions.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.006 A Ê R factor = 0.055 wR factor = 0.133 Data-to-parameter ratio = 15.2 For details of how these key indicators were automatically derived from the article, see