The four E/Z isomers of camphorquinone dioxime (cqdH2) were isolated as far back as 1903. Little attention was paid to the coordination chemistry of these dioximes until the late 1970s. That work focused on the α-isomer (2Z, 3E) and δ-isomer (2E, 3Z), which both coordinate to metals via N, O bonding. Cobalt(II) complexes of α-cqdH are effective chiral cyclopropanation catalysts. While complexes of the “normal” β-isomer (2E, 3E, displaying N, N bonding) have been reported, none have been characterized in any detail and no “cobaloxime” complexes of these ligands have been reported. Cobaloxime complexes of β-camphorquinone dioxime can exist as three different isomers. Preparation of Co(β-cqdH)2(4-Mepy)Br gives all three isomers, but the primary isomer and the one that precipitates from solution has the β-cqdH ligands in a cis orientation about the cobalt. This stereochemistry is confirmed both by NMR spectroscopy and x-ray crystallography. Alkylation of the cobaloxime results is scrambling of the stereochemical isomers, presumably through substitution labile Co(I) and/or Co(II) species. In order to prevent isomerization, the bis BF2 bridged cobaloxime has been prepared and characterized. Alkylation experiments with this complex will be presented. Spectroscopic and electrochemical properties of the cqdH complexes will be compared to other cobaloximes.

Cobaloxime complexes of camphorquinone dioxime

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.