Lanthanide halo complexes

These compounds, together with the halo complexes described in the next section (39.2.7.5), form the bulk of the known complexes of tetrapositive lanthanides. 

Note The Meissenheimer conversion of 1,8-naphthyridine A-oxides into halo-geno-l,8-naphthyridines has been covered in Section 24.1 complexes of 1,8-naphthyridine 1-oxide with Cr,555 Cu,496 and Sr,462 and the lanthanide compounds429 have been reported and deoxygenation of an A-oxide is exemplified here. 

The second t)q)e of cluster compounds of the lanthanide alkoxides features one or several small-unit, inorganic ligands including oxo, hydroxo, halo, and other groups as part of the cluster core structure. Frequently, a combination of such ligands is foimd in the same cluster species. In a sense, this "central spherical charge density" drives the assembly of the polynuclear complexes without their participation, no clusters are formed or species of completely different structures result. 

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