While nitric oxide is well known as a ligand, comparatively little is known about the coordination chemistry of nitric oxide derivatives such as nitrosoalkanes and nitrosoarenes. Some nitrosoalkanes and nitrosoarenes undergo dimerization to form cis- and trans-N,N'-azodioxides. The cis isomers of azodioxides act as bidentate chelating ligands for transition metals. Surprisingly, only two azodioxide metal complexes in the literature have been crystallographically characterized: [Fe{Ph(O)NN(O)Ph}3][FeCl4]2 and [Sc{o-MeOPh(O)NN(O)o-MeOPh}(OTf)3(H2O)2], which have shown substantial π delocalization in their azodioxide ligands. This π delocalization suggests that azodioxides could act as redox-active ligands. While work has been done on synthesizing homoleptic azodioxide complexes, the primary goal of this project is to synthesize and characterize heteroleptic complexes containing both azodioxides and known redox-active ligands such as bipyridyl and catecholates. Thus far, a novel heteroleptic cobalt(II) complex containing azodioxide and bipyridyl ligands has been crystallographically characterized. Current work is being conducted in synthesizing azodioxide/bipyridyl complexes containing different transition metals. Future work will involve synthesizing and characterizing azodioxide/catecholate metal complexes. Additionally, spectroscopic methods will be applied to these newly synthesized complexes to see if they display redox activity. Applications of these synthesized heteroleptic complexes in photo-catalysis and biomimetic catalysis will be explored.

Synthesis of heteroleptic transition-metal complexes containing azodioxide ligands

255th National Meeting (2018)

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