Ringing the changes in Feiii/Ybiii cyclic coordination clusters

Abstract

Five [Fe^III_mYb^III_n] Cyclic Coordination Clusters (CCCs) which show completely different arrangements of their cyclic cores have been synthesised and characterised. These represent five out of seven compounds which were obtained by fine-tuning the reaction conditions (Fe^III-source, Ln^III-salt, chiral/nonchiral aminoalcohol ligands) used previously to synthesise the non-cyclic [Fe₂Yb₂(OH)₂(teaH)₂(O₂CPh)₆] compound 1. Thus the five new CCCs [Fe₅Yb₃(μ₃-OH)(teaH)₇(O₂CPh)₈](CF₃SO₃)·10MeCN (m = 5; n = 2, 2), [Fe₄Yb₂(μ-OH)(μ-OMe)₂(Me-teaH)₄(O₂CPh)₇]·3CH₃CN (m = 4; n = 2, 3), [Fe₃Yb₂(μ-OH)(Me-teaH)₄(O₂CPh)₆]·MeCN (m = 3; n = 2, 4), [Fe₄Yb₂(Me-tea)₄(Me-teaH)₂(OTs)₂]·MeCN·3MeOH (m = 4; n = 2, 5) and [Fe₁₀Yb₁₀(Me-tea)₁₀(Me-teaH)₁₀(NO₃)₁₀]·21MeCN (m = 10; n = 10, 6) as well as the binuclear complex [Yb₂(tipH₂)₂(O₂CPh)₄] (7) are reported. The formation of compounds 2, 3 and 4, which were obtained using [Fe₃O(O₂CCPh)₆(H₂O)₃]⁺ as the source of Fe^III, can be rationalised in terms of cleaving the triangular {Fe^III₃O} starting material into mononuclear and dinuclear Fe^III/benzoate species. Furthermore, it was found that for compounds 3–6, the interplay of ligand chirality, hydrogen-bonding interactions and the nature of anionic species present are decisive directional influences on the resulting nature of the cyclic compounds.