Bis(1,3-diphenylpropane-1,3-dionato-kappa2O,O'){hydrotris[3-(2-pyridyl)pyrazol-1-yl]borato}praseodymium(III): another member of an unpredictable series.

Reaction of praseodymium(III) chloride with stoichometric quantities of dibenzoylmethane (Hdbm) and hydrotris[3-(2-pyridyl)pyrazol-1-yl]borate (Tp 2py) affords the title complex, [Pr(C24H19BN9)(C15H11O4)2]. The lanthanide ion in this ternary complex exhibits an N6O4 ten-coordinate geometry arising from the five bidentate arms found on the anionic ligands. The structure is entirely different from those found in other lanthanide complexes with the same ligand set.