880000-28-2Relevant academic research and scientific papers
Manipulation of reaction pathways in redox transmetallation-ligand exchange syntheses of lanthanoid(ii)/(iii) aryloxide complexes
Deacon, Glen B.,Fallon, Gary D.,Forsyth, Craig M.,Harris, Stuart C.,Junk, Peter C.,Skelton, Brian W.,White, Allan H.
, p. 802 - 812 (2006)
Redox transmetallation/ligand exchange reactions of lanthanoid metals (Ln), Hg(C6F5)2 and HOArOMe (Ar OMe = C6H2-2,6-But-4-OMe), in thf (tetrahydrofuran) gave, for Ln = Yb, Yb(OArOMe)2(thf) 3, and for Ln = Sm, a mixture of SmII(OAr OMe)2(thf)3 and mainly SmIII(Ar OMe)3(thf)·thf. X-Ray structure determinations show the divalent complexes to have distorted square-pyramidal stereochemistry with transoid thf and OArOMe ligands in the basal plane. Treatment of Yb(OArOMe)2(thf)3 with diethyl ether or PhMe at room temperature gave Yb(OArOMe)2 or Yb(OAr OMe)2·0.5PhMe. For lanthanoids Ln = Nd, Er or Y, the reactions with Hg(C6F5)2 and HOAr OMe yielded complex product mixtures, from one of which the novel erbium aryloxide fluoride cage Er3(OArOMe) 4(μ2-F)3(μ3-F) 2(thf)4·thf·0.5C6H14 was isolated. The cage core consists of a triangle of Er atoms joined to two μ3-fluoride ligands and three further μ2-fluorides bridge adjacent Er atoms. One of the Er atoms is six-coordinate with additionally two OArOMe ligands whilst the other two have one OArOMe and two thf ligands and are seven coordinate. Substitution of Hg(C6F5)2 by Hg(CCPh)2 in the redox transmetallation/ligand exchange reactions gave the new derivatives Ln(OAr OMe)3(thf)·thf (Ln = La, Pr, Nd, Sm, Gd, Ho) in good yields whilst Ln = Yb gave Yb(OArOMe)2(thf) 3. Recrystallisation of Sm(OArOMe)3(thf) ·thf from dme (1,2-dimethoxyethane) yielded Sm(OArOMe) 3(dme). Structural characterisation of Ln(OArOMe) 3(thf)·thf (Ln = Nd, Ho) and Sm(OArOMe) 3(dme) showed monomeric four-coordinate distorted tetrahedral and five-coordinate distorted square-pyramidal complexes respectively. For the smaller lanthanoids Ln = Y, Er or Lu, reactions with Hg(CCPh)2 and HOArOMe gave the mixed aryloxide/alkynide complexes Ln(OAr OMe)2(CCPh)(thf)2. Oxidation of the divalent ytterbium aryloxide Yb(OArOMe)2(thf)3 by Hg(CCPh)2 in thf gave the analogous Yb(OArOMe) 2(CCPh)(thf)2. The erbium alkynide Er(OAr OMe)2(CCPh)(thf)2·0.25C 6H14 has distorted square-pyramidal stereochemistry with transoid OArOMe and thf ligands in the basal plane and a rare (for Ln) terminal alkynide ligand in the apical position. The reactive Lu-C bond in the Lu(OArOMe)2(CCPh)(thf)2 complexes could be slowly cleaved by free HOArOMe in hydrocarbon solvents, yielding Lu(OArOMe)3 species and fortuitous partial hydrolysis of Er(ArOMe)2(CCPh)(thf)2 gave the dimeric Er(OArOMe)2(μ-OH)22. The Royal Society of Chemistry 2006.
