Bulky tris(pyrazolyl)borate (Tp) ligands are ubiquitous in enzyme modeling.  Here, the under-utilized analogs, tris(triazolyl)borate (Ttz) ligands, support functional models of the active-site of copper nitrite reductase (CuNiR).  The extra nitrogen on the triazole ring, relative to pyrazole, significantly affects the corresponding copper complexes. Addition of H+ to TtzR1,R2Cu(I)CO complexes dramatically changes the electronic properties of these complexes, presumably through binding the fourth position N.  This interaction could have implications for the reactivity of (TtzR1,R2)CuNOx species.  We report (TtzR1,R2)CuNOx complexes, which show distinct structural and electronic differences when compared to corresponding Tp complexes.  Most notably, [PPN]+[(TtztBu,Me)Cu(I)NO2]- has been synthesized and characterized and allows for stoichiometric nitrite reduction to NO upon addition of acid.  Anionic Cu(I) nitrite complexes are rare and this is the first stabilized by an anionic scorpionate ligand due to the electron withdrawing properties of the triazole rings.

Modeling copper nitrite reductase with tris(triazolyl)borate ligands: The triazole nitrogen's influence on the structure, electronic properties, and reactivity

243rd National Meeting (2012)

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