Nitrenium ions, isoelectronic nitrogen counterparts of carbenes, are important intermediates in various biological and chemical processes. Herein we describe the first synthesis and characterization of a stable nitrenium ion without resonance stabilization by adjoining amino groups. Namely, a stable salt of a diporphyrinylnitrenium ion was synthesized by stepwise oxidation of the corresponding diporphyrinylamine through a stable aminyl radical. The nitrenium ion exhibits characteristic features such as a singlet ground state, enhanced double-bond character of the central C-N bonds, no reactivity toward water and methanol, and negative solvatochromic behavior.
Keywords: EPR; aminyl radicals; disproportionation; nitrenium ions; porphyrins.
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