NN-dialkylcarbamato-complexes of 4f elements

Abstract

By reaction of the anhydrous metal (III) halide with a secondary amine and carbon dioxide in a hydrocarbon solvent, the first NN-dialkylcarbamato-complexes of lanthanide metals have been prepared, [M_n(O₂CNR₂)_3n,](M = Yb or Er). In the case of the ytterbium derivative with R= Prⁱ, the crystal and molecular structure has been solved by X-ray diffraction methods. The complex is a tetramer, [{Yb(O₂CNPrⁱ₂)₃}₄]·2C₇H₁₆; crystals are monoclinic, space group C2/c, with a= 29.069(5), b= 19.591 (3), c= 23.193(4)Å, β= 107.70(2)°, and Z= 4. The four seven-co-ordinate ytterbium atoms are joined by bridging NN-dialkylcarbamato-groups. The ytterbium derivative reacts promptly with proton-active substances yielding the appropriate complex salts, with quantitative evolution of carbon dioxide.