Polymetallic clusters of iron(III) with derivatised salicylaldoximes

The synthesis and magnetic properties of the compounds [HNEt3][Fe-2(OMe)(Ph-sao)(2) (Ph-saoH)(2)]center dot 5MeOH (1.5MeOH), [Fe3O(Et-sao)(O2CPh)(5)(MeOH)(2)]center dot 3MeOH (2.3MeOH), [Fe-4(Me-sao)(4)(Me-saoH)(4)] (3), [HNEt3](2)[Fe6O2(Me-sao)(4)(SO4)(2)(OMe)(4)(MeOH)(2)](4), [Fe8O3(Me-sao)(3)(tea)(teaH)(3)(O2CMe)(3)] (5), [Fe8O3(Et-sao)(3)(tea)(teaH)(3)(O2CMe)(3)] (6), and [Fe8O3(Ph-sao)(3)(tea)(teaH)(3)(O2CMe)(3)] (7) are reported (Me-saoH(2) is 2'-hydroxyacetophenone oxime, Et-saoH(2) is 2'-hydroxypropiophenone oxime and Ph-saoH(2) is 2-hydroxybenzophenone oxime). 1-7 are the first Fe-III compounds synthesised using the derivatised salicylaldoxime ligands, R-saoH(2). 1 is prepared by treatment of Fe-2(SO4)(3)center dot 6H(2)O with Ph-saoH(2) in the presence of NEt3 in MeOH; 2 prepared by treatment of Fe(ClO4)(2)center dot 6H(2)O with Et-saoH(2) and NaO2CPh in the presence of NEt4OH in MeOH; 3 prepared by treatment of Fe(ClO4)(2)center dot 6H(2)O with Me-saoH(2) and NaO2CCMe3 in the presence of NEt4OH in MeOH; and 4 prepared by treatment of Fe-2(SO4)(3)center dot 6H(2)O with Me-saoH(2) in the presence of NEt3 in MeOH. 4 is a rare example of a polynuclear iron complex containing a coordinated SO42- ion. Compounds 5-7 are prepared by treatment of Fe(O2CMe)(2) with Me-saoH(2) (5), Et-saoH(2) (6), Ph-saoH(2) (7) in the presence of H(3)tea (triethanolamine) in MeOH, and represent the largest nuclearity Fe-III clusters containing salicyladoxime-based ligands, joining a surprisingly small family of characterised octanuclear Fe complexes. Variable temperature magnetic susceptibilty measurements of 1,3 and 5-7 reveal all five complexes possess S = 0 spin ground states; 2 possesses an S = 1/2 spin ground state, while 4 has an S = 4 +/- 1 spin ground state.