| Popis: |
Alcoholysis of alkoxides or oxoalkoxides of trivalent metals such as yttrium or bismuth with 2-methoxyethanol at room temperature gives highly soluble cyclic or linear oligomers or polymers [M(0C 2 H 4 0Me) 3 ] m M = Y, m = 10; M = Bi, m = ∞, which have been structurally characterized. Their common feature is the preponderance of the bridging μ 2 ,n 2 or μ,n 1 coordination modes over the chelating mode. The 2-methoxyethoxide group generally favors high coordination numbers, and thus even for divalent metals, this is achieved by μ 3 ,n 2 or μ 3 ,n 1 coordination modes as in Cd 9 (0C 2 H 4 0Me) 18 ,20HC 2 H 4 0Me. The lability of the alkoxyethoxide ligand allows further tailoring of the properties of the precursors, especially the reduction of the size of the metal aggregates by modifiers such as acetylacetone, added either as a free ligand or via metal acetylacetonates. |
