Partial and exhaustive hydrolysis of lanthanide N,N-dialkylcarbamato complexes. A viable access to lanthanide mixed oxides

Partial hydrolysis (H2O/Ln molar ratio = ¼) of lanthanum di-iso-propylcarbamato complex, [La(O2CNiPr2)3], 1, afforded the tetranuclear μ-oxo derivative [La4O(O2CNiPr2)10], 2, which was structurally characterized by single crystal X-Ray diffraction studies. The carbonatocarbamato derivative of lanthanum, [La4(CO3)(O2CNBu2)10], 3, was prepared by extraction of lanthanum ions from aqueous solution into heptane by the NHBu2/CO2 system. Partial hydrolysis (H2O/Ln molar ratio = ½ ) of N,N-di-iso-propylcarbamato complexes of neodymium, europium, gadolinium and terbium, [Ln(O2CNiPr2)3], yielded the derivatives [Ln2(CO3)(O2CNiPr2)4] (Ln = Nd, 4, Eu, 5, Gd, 6). Exhaustive hydrolysis of [Ln(O2CNR2)3] (Ln = Nd, Tb, R = Bu; Ln = Eu, Gd, R = iPr, Bu) produced hydrated lanthanide carbonates, Ln2(CO3)3 n H2O. For sake of comparison with a block d metal, the exhaustive hydrolysis of two copper(II) carbamato complexes, [Cu(O2CNEt2)2(NHEt2)]2 and [Cu(O2CNiPr2)2], was carried out with formation in both cases of the hydrated basic carbonate Cu2(OH)2(CO3)nH2O. The exhaustive hydrolysis of mixtures of cerium and lanthanum or cerium and terbium N,N-dibutylcarbamato complexes allowed the preparation of mixed oxides containing the two metals in the desired molar ratio, via the intermediate formation of the corresponding mixed carbonates.