Homoleptic anionic aryloxolanthanoid(III) complexes

Several anionic complexes of lanthanoid metals with the 2,6-diphenylphenolate ligand have been synthesized and their room-temperature single-crystal structures determined. In novel reactions of anhydrous LnCl(3) (Ln = Nd or Er) with NaOC6H3Ph2-2,6 . 0.5thf (thf=tetrahydrofuran) in 1,3,5-tri-tert-butylbenzene at 300 degrees C, complexes of the type [Na{Ln(OC6H3Ph2-2,6)(4)}] were obtained. Crystallisation of [Na{Nd(OC6H3Ph2-2,6)(4)}] from bis(2-methoxyethyl) ether (diglyme) or 1,2-dimethoxyethane (dme) afforded the corresponding solvated complexes [Na(diglyme)(2)][Nd(OC6H3Ph2-2,6)(4)] or [Na(dme)(3)][Nd(OC6H3Ph2-2,6)(4)] respectively, and from an analogous reaction for Ln = Er [Na(diglyme)(2)][Er(OC6H3Ph2-2,6)(4)] was isolated. The complexes [Na(diglyme)(2)][Ln(OC6H3Ph2-2,6)(4)] (Ln = Nd or Pr) are isomorphous. Their structures revealed novel discrete homoleptic tetrakis(aryloxo)lanthanoid(III) anions, well separated from the solvated sodium cations. Annealing the reaction mixture for the synthesis of [Na{Nd(OC6H3Ph2-2,6)(4)}] at 120 degrees C gave single crystals of a monomeric bimetallic in which the sodium ion is encapsulated by three aryloxide oxygens as well as by three phenyl rings of the phenolate ligand, and neodymium is surrounded by a highly distorted tetrahedral arrangement of aryloxide oxygens. There are also intramolecular pi-Ph-M (M = Na or Nd) interactions.