Preparation and x-ray crystal structure of a seven-coordinate cobalt(II) complex with 2,6-diacetylpyridine bis(2-picolinoylhydrazone)

Summary A new seven-coordinate cobalt(II) complex has been synthesized with 2,6-diacetylpyridine bis(2-picolinoylhydrazone) (H₂dappc) and its crystal and molecular structure has been determined by x-ray diffraction methods from counter data and refined toR 0.0449 for 2128 observed reflections. The complex crystallizes in a triclinic cell, space group P¯1, with dimensions:a=13.759(8),b=7.685(3),c=13.816(7) Å, =86.50(5), =66.48(5), =85.28(5)° andZ=2. The complete structure consists of Co(H₂dappc)(OH₂)₂] cations, chloride anions and solvating H₂O molecules, interlinked by hydrogen bonds. The geometry around the cobalt is that of a distorted pentagonal bipyramid with the H₂dappc ligand forming the equatorial plane and two H₂O molecules occupying the axial positions.