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Exhaustive hydrolysis of a mixture of [La 4 (CO 3 )(O 2 CNBu 2 ) 10 ] and [Cu(O 2 CNBu 2 )(py ∗ ) 2 ] (py ∗ = 4-dimethylamino pyridine) in molar ratio 1/2 corresponding to a La/Cu molar ratio 2/1 was carried out in toluene at room temperature. The carbamato derivatives of lanthanum and copper can be easily prepared by extraction of the metal ions from aqueous solution into heptane by the NHBu 2 /CO 2 system, according to a method previously reported. The copper precursor was selected amongst a number of derivatives in respect of its easy tractability. The tetragonal modification T′ of La 2 CuO 4 was obtained by treatment at 600 °C of the intermediate mixed carbonate. The thermal treatment of T′-La 2 CuO 4 at 850 °C, followed by cooling down to room temperature, afforded the orthorhombic modification of the mixed oxide. [ABSTRACT FROM AUTHOR]

Partial hydrolysis (H 2 O/Ln molar ratio = ¼) of lanthanum di- iso -propylcarbamato complex, [La(O 2 CN i Pr 2 ) 3 ], 1 , afforded the tetranuclear μ-oxo derivative [La 4 O(O 2 CN i Pr 2 ) 10 ], 2 , which was structurally characterized by single crystal X-ray diffraction studies. The carbonato–carbamato derivative of lanthanum, [La 4 (CO 3 )(O 2 CNBu 2 ) 10 ], 3 , was prepared by extraction of lanthanum ions from aqueous solution into heptane by the NHBu 2 /CO 2 system. Partial hydrolysis (H 2 O/Ln molar ratio = ½) of N , N -di-iso-propylcarbamato complexes of neodymium, europium, gadolinium and terbium, [Ln(O 2 CN i Pr 2 ) 3 ], yielded the derivatives [Ln 2 (CO 3 )(O 2 CN i Pr 2 ) 4 ] (Ln = Nd, 4 , Eu, 5 , Gd, 6 ). Exhaustive hydrolysis of [Ln(O 2 CNR 2 ) 3 ] (Ln = Nd, Tb, R = Bu; Ln = Eu, Gd, R = i Pr, Bu) produced hydrated lanthanide carbonates, Ln 2 (CO 3 ) 3 · n H 2 O. For sake of comparison with a block d metal, the exhaustive hydrolysis of two copper(II) carbamato complexes, [Cu(O 2 CNEt 2 ) 2 (NHEt 2 )] 2 and [Cu(O 2 CN i Pr 2 ) 2 ], was carried out with formation in both cases of the hydrated basic carbonate Cu 2 (OH) 2 (CO 3 )· n H 2 O. 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. [ABSTRACT FROM AUTHOR]

Nanostructured ceria has been prepared in mild conditions by hydrolysis of the N , N -dibutylcarbamato complex of cerium(III), [Ce(O 2 CNBu 2 ) 3 ], obtained by lanthanide extraction from aqueous solution into heptane containing CO 2 saturated NHBu 2 . In dependence of the hydrolysis conditions, cerium(III) carbonates or hydroxocarbonate (characterized by IR, XRD and metal content) were obtained. Thermal treatment of these products at relatively low temperature (200 °C) yielded CeO 2 in the form of a light yellow powder. The structure and morphology of the samples were studied by TEM, FESEM and XRD studies. The medium crystallite dimensions, estimated by TEM, appear to be of a few nanometers. Ceria with smaller medium crystallite dimensions was obtained by increasing the amine concentration in the course of the hydrolysis process. [ABSTRACT FROM AUTHOR]