Linking [M-3(III)] triangles with "double-headed" phenolic oximes

Strapping two salicylaldoxime units together with aliphatic alpha,Omega-aminomethyl links in the 3-position gives ligands which allow the assembly of the polynuclear complexes [Fe7O2(OH)(6)(H(2)L1)(3)(py)(6)] (BF4)(5)center dot 6H(2)O center dot 14MeOH (1 center dot 6H(2)O center dot 14MeOH), [Fe6O(OH)(7)(H2L2)(3)](BF4)(3)center dot 4H(2)O center dot 9MeOH (2 center dot 4H(2)O center dot 9MeOH) and [Mn6O2(OH)(2)(H(2)L1)(3)(py)(4)(MeCN)(2)](BF4)(5)(NO3)center dot 3MeCN center dot H2O center dot 5py (3 center dot 3MeCN center dot H2O center dot 5py). In each case the metallic skeleton of the cluster is based on a trigonal prism in which two [(M3O)-O-III] triangles are tethered together via three helically twisted double-headed oximes. The latter are present as H2L2- in which the oximic and phenolic O-atoms are deprotonated and the amino N-atoms protonated, with the oxime moieties bridging across the edges of the metal triangles. Both the identity of the metal ion and the length of the straps connecting the salicylaldoxime units have a major impact on the nuclearity and topology of the resultant cluster, with, perhaps counter-intuitively, the longer straps producing the "smallest" molecules.