An example of the refinement of positional disorder modeled as compositional disorder in [5-(2-formyl­phen­yl)-10,15,20-triphenyl­porphyrinato]nickel(II)

The title compound, [Ni(C₄₅H₂₈N₄O)], crystallizes in the space group I2d and resides on a crystallographic fourfold rotoinversion axis with only a quarter of the complex in the asymmetric unit. The complex displays positional disorder as the one aldehyde group on the ligand can be located at four different positions. It was necessary to model this as com­po­sitional disorder to obtain a correct model and refinement. The practical approach to the refinement is explained.

Dichlorido{2-[(3,5-diphenyl-1H-pyra­zol-1-yl-κN²)meth­yl]pyridine-κN}palladium(II)

The title compound, [PdCl₂(C₂₁H₁₇N₃)], is a member of a sequence of Pd, Pt and Co dichloride complexes bearing polysubstituted (pyrazol-1-ylmeth­yl)pyridine ligands. It is shown that there is a correlation between the steric bulkiness of the bidentate (pyrazol-1-ylmeth­yl)pyridine ligands and the Pd—N_pyrazole distances, i.e. the larger the ligand, the longer the bond. In contrast, no trend is observed between the steric properties of the ligand and the Pd—N_pyridine bond lengths.