ORGANOAMIDO-LATHANIDES AND ARYLOXO-LANTHANIDES .8. THE X-RAY STRUCTURE OF 5-COORDINATE [LA(OC6H3PH2-2,6)3(THF)2].THF

The X-ray crystal structure of [La(Odpp)3(THF)2].THF (Odpp = OC6H3Ph2- 2,6), prepared by reaction of lanthanum metal, bis(pentafluorophenyl)m ercury and 2,6-diphenylphenol in THF, shows distorted trigonal-bipyram idal stereochemistry for lanthanum. A phenolate oxygen [La-O 2.25(1) a ngstrom] and a THF oxygen [La-O 2.68(2) angstrom] occupy apical positi ons [O-La-O 165.9(4)-degrees], whilst two phenolate oxygens [La-O 2.25 (1), 2.234(9) angstrom] and a THF oxygen [La-O 2.52(1) angstrom] occup y trigonal positions [O-La-O 122.1(4), 124.8(5), 96.5(6)-degrees]. The apical La-O(THF) distance is exceptionally and unexpectedly long. Uni t cell data for [Nd(OdPP)3(THF)2].THF suggest that it is isostructural with the lanthanum compound.