Methyltrihydroborate complexes of the actinides and lanthanides

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5514241

Shinomoto, R S

The reaction of MCl/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/. The U(IV) and Th(IV) methyltrihydroborates readily form Lewis base adducts. The adducts prepared are described in detail, and their dimerization is discussed. A steric model has been used to justify the stoichiometry and structures of M(BH/sub 3/CH/sub 3/)/sub 4/ and M(BH/sub 4/)/sub 4/ (M = U, Th) base adducts. The bidentate base adducts of U(BH/sub 3/CH/sub 3/)/sub 4/ show dynamic behavior. The pseudooctahedral species have two nonequivalent BH/sub 3/CH/sub 3/ sites in the solid state, two trans and two cis to the bidentate ligand. These two sites exchange rapidly at room temperature in solution but exchange can be slowed appreciably at lower temperatures so as to observe two nonequivalent BH/sub 3/CH/sub 3/ sites on the /sup 1/H NMR time scale. A twisting mechanism has been proposed based on measured ..delta..G values for two site exchange. The U(III) species, U(BH/sub 3/CH/sub 3/)/sub 3/.2dmpe, has also been prepared by thermal decomposition of U(BH/sub 3/CH/sub 3/)/sub 4/.dmpe in toluene in the presence of excess dmpe. The reaction of MCl/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/. Lewis base adducts prepared from M(BH/sub 3/CH/sub 3/)/sub 3/.OEt/sub 2/ are discussed. By structural criteria, the bonding in actinide and lanthanide methyltrihydroborate complexes is primarily ionic in character even through 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/.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5514241
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPLEXES
ALKANES
BASES
BORON COMPOUNDS
BORON HYDRIDES
COMPLEXES
HAFNIUM COMPLEXES
HOLMIUM COMPLEXES
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
LEWIS ACIDS
LEWIS BASES
LUTETIUM COMPLEXES
METHANE
MOLECULAR STRUCTURE
NEPTUNIUM COMPLEXES
ORGANIC COMPOUNDS
RARE EARTH COMPLEXES
STEREOCHEMISTRY
THORIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
TRANSURANIUM COMPLEXES
URANIUM COMPLEXES
YTTERBIUM COMPLEXES
ZIRCONIUM COMPLEXES