Facile synthesis of rare-earth pyrazolonates by the reaction of rare-earth metals with 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone. Crystal structures of [Ln(PMIP)3]2 (Ln = Y, Gd, Tb, Er, Tm)

Rare-earth pyrazolonates Ln(PMIP)3 (Ln = Y, Nd, Gd, Tb, Er, Tm, Lu) were synthesized in high yields by the reaction of 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone (HPMIP) with rare-earth metals in the presence of catalytic amount of LnI3. The isolated compounds were found to sublime in vacuum (10−3 Torr) in the temperature range of 230–265 °C. Single crystal X-ray analyses of the sublimed rare-earth complexes revealed dimmers [Ln(PMIP)3]2 (Ln = Y, Gd, Tb, Er, Tm) in which rare-earth metals are bridged by pyrazolonate units. The coordination environment of the metal atoms can be described as distorted monocapped trigonal prism.