Hexametallic manganese clusters with bulky derivatised salicylaldoximes

Abstract

The reaction of Mn(ClO₄)₂·6H₂O with Ph-saoH₂ (Ph-saoH₂ = 2-hydroxybenzophenone oxime) in MeCN in the presence of sodium propionate forms the complex [Mn^III₆O₂(Ph-sao)₆(prop)₂(MeCN)₂]·5.27MeCN (1·5.27MeCN) (prop = propionate). Repeating the same reaction in EtOH produces the complex [Mn^III₆O₂(Ph-sao)₆(prop)₂(EtOH)₄] (2). Complexes 1 and 2 may be considered as structural isomers, since they display the same metallic core but different coordination modes of the propionate ligands; bridging in 1 and terminal in 2. Performing similar reactions and switching from sodium propionate to sodium adamantane-carboxylate (NaO₂C-ada) and sodium pivalate (Napiv) in the presence of NEt₄OH yields the complexes [Mn^III₆O₂(Ph-sao)₆(O₂C-ada)₂(MeOH)₄] (3) and [Mn^III₆O₂(Ph-sao)₆(piv)₂(EtOH)₄]·0.5Et₂O (4·0.5Et₂O), respectively. All four complexes contain the same {Mn^III₃O(Ph-sao)₃} building block. Variable temperature magnetic susceptibility and magnetization studies show that all complexes possess an S = 4 ground-state.