
%0 Journal Article
%A Deacon, Glen B. 
%A Feng, Tiecheng 
%A Junk, Peter C. 
%A Meyer, Gerd 
%A Scott, Natalie M. 
%A Skelton, Brian W. 
%A White, Allan H. 
%T Structural Variety in Solvated Lanthanoid(III ) Halide Complexes
%J Australian Journal of Chemistry
%D 2001/04/05
%V 53
%N 10
%P 853-865
%K Lanthanoid halides, lanthanum, ytterbium.
%R https://doi.org/10.1071/CH00117
%U https://www.publish.csiro.au/paper/CH00117 
%X Treatment of lanthanum metal with CH2Br2 or CH2I2 in tetrahydrofuran (thf) under ultrasound conditions yields the corresponding &#91;LaX3(thf)4&#93; (X = Br, I) complexes in good yield. Recrystallization of &#91;LaBr3(thf)4&#93; from 1,2-dimethoxyethane (dme) or bis(2-methoxyethyl) ether (diglyme) generates &#91;LaBr2(&#181;-Br)(dme)2&#93;2 and &#91;LaBr2(dig-lyme)2&#93;&#91;LaBr4(diglyme)&#93;. Treatment of lanthanoid metals with hexachloroethane in dme yields &#91;LnCl3(dme)2&#93; (Ln = La, Nd, Er or Yb) and in acetonitrile &#91;YbCl2(MeCN)5&#93;2&#91;YbCl3(MeCN)(-Cl)2YbCl3(MeCN)&#93;. The reaction of Yb metal pieces with 1,2-dibromoethane in thf and dme gave single crystals of &#91;YbBr3(thf)3&#93; and &#91;YbBr3(dme)2&#93;, respectively. The X-ray determined structure of &#91;LaBr3(thf)4&#93; shows a seven-coordinate monomer with pentagonal-bipyramidal stereochemistry and apical bromide ligands. For &#91;YbBr3(thf)3&#93;, a monomeric structure with mer-octa-hedral stereochemistry is observed. In &#91;LaBr2(&#181;-Br)(dme)2&#93;2, two eight-coordinate La centres are linked by two bridging bromides. The dme ligands have a trans relationship to each other, and cis terminal bromides are transoid to the bridging bromides with dodecahedral stereochemistry for La. By contrast, the 1: 1.5 diglyme adduct is found to be ionic &#91;LaBr2(diglyme)2&#93;&#91;LaBr4(diglyme)&#93;, with an eight-coordinate bicapped trigonal-prismatic lanthanum cation and a seven-coordinate pentagonal-bipyramidal lanthanum anion. In the cation, the bromide ligands are cis to each other, and in the anion, two bromides are equatorial and two are axial. In &#91;YbBr3(dme)2&#93;, &#91;YbCl3(dme)2&#93; and &#91;ErCl3(dme)2&#93;, a seven-coordinate pentagonal-bipyramidal arrangement exists with apical halogen ligands. Far-infrared data, and in particular the absence of absorptions attributable to &Igrave;(La&#8211;Clter), suggest that &#91;LaCl3(dme)&#93; is polymeric with six bridging chlorides per lanthanum. For &#91;YbCl2(MeCN)5&#93;2&#91;YbCl3(MeCN)(-Cl)2YbCl3-(MeCN)&#93;, a remarkable ionic structure, with pentagonal-bipyramidal &#91;YbCl2(MeCN)5&#93;+ cations and octahedral di-nuclear &#91;YbCl3(MeCN)(-Cl)2YbCl3(MeCN)&#93;2&#8211; counter ions, is observed. In the former, chloride ligands are apical, while the MeCN ligands of the latter are transoid. 
