Building Fe(iii)clusters with derivatised salicylaldoximes

Abstract

The syntheses, structures and magnetic properties of nine new iron complexes containing salicylaldoxime (saoH₂) 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 (3·1.5MeOH), [Fe₆O₂(OH)₂(Et-sao)₂(Et-saoH)₂(O₂CPh)₆] (4), [HNEt₃]₂[Fe₆O₂(OH)₂(Et-sao)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(Me-sao)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.