Methyltrihydroborate Complexes of the Lanthanides and Actinides

摘要

Reaction of MC1 sub 4 (M = Zr, Hf, U, Th, Np) with LiBH sub 3 CH sub 3 in chlorobenzene produces volatile, hexane-soluble M(BH sub 3 CH sub 3 ) sub 4 . Crystal structures are monomeric, tetrahedral species. Lewis base adducts prepared include U(BH sub 3 CH sub 3 ) sub 4 .THT, Th(BH sub 3 CH sub 3 ) sub 4 .L (L = THF (tetrahydrofuran), THT (tetrahydrothiophene), SMe sub 2 , OMe sub 2 ), U(BH sub 3 CH sub 3 ) sub 4 .2L (L = THF, pyridine, NH sub 3 ), Th(BH sub 3 CH sub 3 ) sub 4 .2L (L = THF, THT, py, NH sub 3 ), M(BH sub 3 CH sub 3 ) sub 4 .L-L (M = U, Th; L-L = dme (1,2-dimethoxyethane), bmte (bis(1,2-methylthio)ethane), tmed (N,N,N',N'-tetramethylethylenediamine), dmpe (1,2-dimethylphosphinoethane)) and Th(BH sub 3 CH sub 3 ) sub 4 .1/2 OEt sub 2 . Reaction of MC1 sub 3 (M = Ho, Yb, Lu) with LiBH sub 3 CH sub 3 in diethyl ether produces volatile, toluene-soluble M(BH sub 3 CH sub 3 ) sub 3 .OEt sub 2 . Other Lewis base adducts prepared from M(BH sub 3 CH sub 3 ) sub 3 .OEt sub 2 include Ho(BH sub 3 CH sub 3 ) sub 3 .L (L = THT, THF, py), Ho(BH sub 3 CH sub 3 ) sub 3 .2L (L = THT, THF, py), Ho(BH sub 3 CH sub 3 ) sub 3 .tmed, Ho(BH sub 3 CH sub 3 ) sub 3 .3/2 L-L (L-L = dmpe, bmte), Yb(BH sub 3 CH sub 3 ) sub 3 .3/2 dmpe, Yb(BH sub 3 Ch sub 3 ).L (L = THF, dme), Yb(BH sub 3 CH sub 3 ) sub 3 .2THF, and Lu(BH sub 3 CH sub 3 ) sub 3 .THF. By structural criteria, the bonding in actinide and lanthanide methyltrihydroborate complexes is primarily ionic in character even though they display covalent-like physical properties. Spectroscopic measurements indicate that there is some degree of covalent bonding in U(BH sub 3 CH sub 3 ) sub 4 . (ERA citation 10:010165)