Dinuclear Iron, Cobalt and Uranium Complexes of New Diamidoether Ligands

Abstract

A series of new diamidoether ligands of the form {[RN(SiMe2)]2O}2- (R = 2,4,6-Me3Ph, 2,6-iPr2Ph, 3,5-(CF3)2Ph), termed [RNON]2-, were prepared via dilithiation of the precursors H2[RNON], which were synthesized from the reaction of O(SiMe2Cl)2 with the appropriate lithium amide. Reaction of the previously reported Li2[tBuNON] with FeX3 (X=C1, Br) yields dinuclear halide-bridged iron(III) complexes that show an unusual quantum spin-admixed magnetic state. Complexes of iron(III) with the aryl-NON ligands, however, form rare lithium “ate” structures. {[RNON]Co}2 complexes (R=tBu, 2,4,6-Me3Ph) are dinuclear with amido bridges and Co-Co bonds. Each Co(II) centre is roughly trigonal monopyramidal. The analogous reactions with UO2C12(THF)3 give dark red powders. For R=tBu, {UO2[tBuNON]}2 complexes are formed that may have structures similar to {[RNON]Co}2.