These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 09.12.2019 and posted on 17.12.2019by Zeinab Sakhaei, Subrata Kundu, Jeffery A. Bertke, Timothy H. Warren
Nitrite is involved in a plethora of biological phenomena that includes tyrosine nitration associated with neurodegenerative disorders and gastric phenol metabolism. Reaction of the b-diketiminato model complex [Cl2NNF6]Cu(k2-O2N) with phenols outlines the coupled generation of NO with phenol oxidation by nitrite at copper(II). Kinetic studies support nucleophilic attack of the hydroxyl group of phenols ArOH on the bound nitrite in [CuII](k2-O2N) to give the copper(II) hydroxide [CuII]-OH along with the O-nitrosated phenol ArONO that ultimately leads to the corresponding biphenol or o-nitrophenol. The especially electron-rich antioxidant a-tocapherol (vitamin E) quickly generates NO upon interaction with [CuII](k2-O2N). X-ray analysis of the oxidation products of the a-tocapherol analogue PMC reveal formation of an elusive O-quinone methide bound to [CuI], revealing two electron oxidation of PMC by [CuII](k2-O2N). These studies illustrate anaerobic pathways that generate NO from nitrite at copper(II) sites that result in phenol oxidation.