Complexes of heteroscorpionate trispyrazolylborate anionic ligands. Part V. X-ray crystallographic studies of cobalt(II) complexes with hydrobis (3,5-dimethylpyrazolyl)(3,5-diphenylpyrazolyl)borate and hydrobis(3,5-diphenylpyrazolyl)(3,5-dimethylpyrazolyl)borate ligands

Synthesis of poly(pyrazolyl)borate anionic ligands composed of 3,5-dimethyl - and 3,5-diphenylpyrazoles gave two heteroscorpionate tris(pyrazolyl)borat e anionic ligands (Tp'): hydrobis(3,5-dimethylpyrazolyl)(3,5-diphenylpyrazo lyl)borate and hydrobis(3,5-diphenylpyrazolyl) (3,5 -dimethylpyrazolyl)bora te, which were converted into high-spin cobalt(H) complexes. The molecular structure of hexacoordinate tetrahydrofuran hydrobis(3,5-dimethylpyrazolyl) (3,5-diphenylpyrazolyl)boratocobalt(II) nitrate and [dihydrobis(3,5-dipheny lpyrazolyl)borato][hydrobis(3,5-diphenylpyrazolyl) (3,5-dimethylpyrazolyl)b orato]cobalt(II) complexes were established by X-ray crystallography. The T p' ligands are kappa (3) bound to the central metal ion in both complexes. The coordination sphere is completed with three oxygen donors from the nitr ate anion and tetrahydrofuran in the former compound and two nitrogen donor s and a boron-attached hydrogen from the dihydrobis(3,5-diphenylpyrazolyl)b orate ligand with a 2.035 Angstrom Co-H bond in the latter complex. (C) 200 1 Published by Elsevier Science Ltd.