Heteropolymetallic complexes, their preparation and their use in the preparation of oxides, especially of superconducting oxides

摘要

The invention relates to heteropolymetallic complexes, to their preparation and to their use in the preparation of oxides, especially of superconducting oxides. The subject of the invention is the use of HzLi ligands for the formation of heteropolymetallic complexes. These ligands correspond to the general formula (I) IMAGE in which A represents an -OR or -NH-R radical, -R representing -H, -CnH2n-B, IMAGE or IMAGE , with -B denoting -H, -OH, -COOH, -COO-CmH2m+1 or IMAGE , each R1 and R2 substituent representing an alkyl radical having from 1 to 4 carbon atoms, or else R1 and R2 together forming a nitrogenous heterocycle optionally incorporating a second hetero atom such as oxygen or nitrogen, n and m each denoting an integer ranging from 1 to 4. The complexes correspond to the general formula (II) IMAGE in which - M denotes a metal chosen from group IIA metals, group IIIB metals and rare-earth metals, - X denotes -O or -NR, -R having the meaning given above, - j denotes the maximum oxidation state (number) of the metal M, - and p is an integer greater than 1. The complexes obtained can be used in the preparation of trimetal oxides, especially in the preparation of superconducting trimetal oxides such as YBa2Cu3O6+x.