The synthesis and characterization of a new (E,E)-dioxime and its homo- and heterotrinuclear complexes containing a hexaoxadiaza macrobicycle moiety

Abstract

The novel quinoxaline substituted (E,E)-dioxime (H₂L) containing a hexaoxadiaza macrobicycle [2.2.2_B] has been synthesized from the reaction of 4,7,13,16,21,24-hexaoxa-5,6-(2′,3′-diaminobenzo)-1,10-diazabicyclo[8.8.8]hexacosane (4) prepared from 4,7,13,16,21,24-hexaoxa-5,6-(2′,3′-dinitrobenzo)-1,10-diazabicyclo[8.8.8]hexacosane (3) and cyanogendi-N-oxide (5). Only the mononuclear nickel(II) complex with a metal∶ligand ratio of 1∶2 was prepared. This hydrogen-bridged complex was converted into its BF₂⁺ capped analogue by reaction with BF₃·Et₂O. The reaction of the BF₂⁺ bridged complex with KPF₆ gave a heterotrinuclear complex. Structures for the dioxime and its complexes are proposed in accordance with elemental analysis, ¹H and ¹³C NMR, IR and MS spectral data.