Two-electron reduction of (n^6-Naphthalene) tricarbonylchromium. Haptotropic rearrangement to the (n^4-Naphthalene)tricarbonylchromium dianion

Abstract

The electrochemical and chemical reduction of (n^6-naphthalene)tricarbonylchromium is a two-electron ECE reduction. The chemical step is a haptotropic rearrangement, which leads ultimately to the (n^4-naphthalene)tricarbonylchromium dianion. The dianion displays some unusual 13c NMR features that provide strong support for the proposed "slip-fold" mechanism. Reaction of the dianion with a proton source produces a (n^5-cyclohexadienyl)tricarbonylchromium anion species, which can be oxidized to the original naphthalene complex. Molecular orbital arguments support the "slip-fold" mechanism. Finally, complete electrochemical reductive properties of the naphthalene complex are presented (Refer to PDF file for exact formulas).