Tris(pyridin-2-ylmethanol)nickel(II) hexafluoridophosphate trifluoroacetate

In the crystal structure of the title complex, [Ni(C6H7NO)3](PF6)(C2F3O2), the NiII ion is in a slightly distorted octahedral NiO3N3 coordination geometry with each of the three N and three O atoms in a meridional coordination. In the crystal, the complex molecules and the trifluoroacetate anions are connected via O—H⋯O hydrogen bonding into layers parallel to the ab plane.

In the crystal structure of the title complex, [Ni(C 6 H 7 NO) 3 ]-(PF 6 )(C 2 F 3 O 2 ), the Ni II ion is in a slightly distorted octahedral NiO 3 N 3 coordination geometry with each of the three N and three O atoms in a meridional coordination. In the crystal, the complex molecules and the trifluoroacetate anions are connected via O-HÁ Á ÁO hydrogen bonding into layers parallel to the ab plane.

Comment
The crystal structure of the title compound is composed of [Ni II (C 6 H 7 ON) 3 ] 2+ cations, hexafluorophosphate and trifluoroacetate anions. The Ni II ion is in a slightly distorted octahedral coordination, comprising three N atoms and three O atoms from three pyridine-2-methanol ligands ( Fig. 1 and Table 1). The three N and three O atoms make a meridional NiO 3 N 3 coordination and the mean bite angle of the pyridine-2-methanol ligand amount to 78.2 (2) °.
In the crystal structure the complexes are connected via O-H···O hydrogen bonding between the hydroxy H atoms of the pyridine-2-methanol ligand and the O atoms of the trifluoroacetate anion into layers that are parallel to the a/b plane.  Table 2).

Experimental
A solution of NiSO 4 .6H 2 O (0.5 mmol) in H 2 O (1 ml) was added to the solution of pyridine-2-methanol (1.5 mmol) in H 2 O (3 ml). Afterwards NH 4 PF 6 (6.0 mmol) and CF 3 COONa (2.5 mmol) were added to the resulting blue solution. The resulting pale blue precipitate was collected. The crude product was purified by recrystallization from acetone and water. The blue prism-like crystals were obtained a few days later on slow evaporation of the solvent.

Refinement
The O-H H atoms were located in a difference Fourier map and the coordinates were fixed. Their U iso (H) values were set to 1.5U eq (O). Other H atoms were placed at calculated positions and were treated as riding on the parent C atoms, with C-H = 0.93 (CH) and 0.97 (CH 2 ) Å and with U iso (H) = 1.2U eq (C). Three F atoms in CF 3 COO anions are rotationally disordered between three positions. The two parts of lower occupation were refined only isotropic (sof. 0.6:0.24:0.16). Fig. 1. ORTEP drawing for the title complex with labeling showing 50% probability displacement ellipsoids. Please note: The trifluoroacetate anion is disordered.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.