| Abstract: | 2?:?1 (L?:?M) Complexes of 2,6-bis(hydroxymethyl)pyridine (dhmp) with different Co(II) salts CoCl2·6H2O, Co(SCN)2, Co(NO3)2·6H2O, CoSO4·7H2O and Co(OTos)2·6H2O] and Ni(II) salts NiCl2·6H2O, Ni(NO3)2·6H2O, NiSO4·7H2O and Ni(OTos)2·6H2O] have been prepared (1–9) and studied by infrared spectroscopy and X-ray crystallography. Influences on the distortion of the coordination polyhedron, the arrangement of the donor atoms and the packing structure of the complexes were investigated in terms of the different kinds of anions and cations. In the metal chloride Complexes 1 and 2, water of hydration was found, while in Complex 3 the counterion (SCN–) acts as a ligand. The crystal structures of all complexes, except 3, show N2O4 hexacoordinated metal ions; in 3 the coordination environment is N4O2. Complex 1 is another exception in containing cobalt(III) instead of cobalt(II) as for the other complexes with cobalt salts. Logically, in Complex 1, one of the dhmp ligands is mono-deprotonated. In the neutral Complexes 2 and 4–9, the basal planes of the octahedra are made up of O donors and N atoms occupy the axial positions. In 1 as well as in 3, two N and two O atoms form the base, but in 1 O, and in 3 N atoms are on the axis of the coordination sphere. Moreover, the nickel Complexes 2, 5, 7 and 9 are more symmetrical in structure than the cobalt Complexes 1, 4, 6 and 8, in accordance with the Jahn–Teller effect. Packing structures of the complexes show specific interactions based on strong and weak H-bonds that involve the counterions, hydroxy groups and aromatic units, leading to extended network structures. |
