Building Fe(III) clusters with derivatised salicylaldoximes

The syntheses, structures and magnetic properties of nine new iron complexes containing salicylaldoxime (saoH 2) or derivatised salicylaldoximes (R-saoH2), [Fe3O(OMe)(Ph-sao)2 Cl2(py)3]·2MeOH (1·2MeOH), [Fe3O(OMe)(Ph-sao)2Br2(py)3]·Et2O (2·Et2O), [Fe4(Ph-sao)4F4(py)4]·1.5MeOH (3·1.5 MeOH), [Fe6O2(OH)2(Et-sao)2(Et-saoH)2(O2CPh)6] (4), [HNEt3]2[Fe6O2(OH)2(Etsao)4(O2CPh(Me)2)6]·2MeCN (5·2MeCN), [Fe6O2(O2CPh)10(3-tBut-5-NO2-sao)2(H2O)2]·2MeCN (6·2MeCN), [Fe6O2(O2CCH2Ph)10(3-tBut-sao)2(H2O)2]·5MeCN (7·5MeCN), {[Fe6Na3O(OH)4(Mesao) 6(OMe)3(H2O)3(MeOH)6]·MeOH}n (8·MeOH) and [HNEt3]2[Fe12Na4O2(OH)8(sao)12(OMe)6(MeOH)10] (9) are discussed. The predominant building block appears to be the triangular [Fe3O(R-sao)3]+ species which can self-assemble into more elaborate arrays depending on reaction conditions. An interesting observation is that the R-saoH-/R-sao2- ligand system tends to adopt coordination modes similar to carboxylates. The most unusual molecule is the [Fe4F4] molecular square, 3. While Cl- and Br- appear to act only as terminal ligands, the F- ions bridge making a telling impact on molecular structure and topology.