A Simple Complex on the Verge of Breakdown: Isolation of the Elusive Cyanoformate Ion
Murphy, L., Robertson, K., Harroun, S., Brosseau, C., Werner-Zwanziger, U., Moilanen, J., . . . , & Clyburne, J. (2014). A Simple Complex on the Verge of Breakdown: Isolation of the Elusive Cyanoformate Ion. Science, 344 (6179), 75-78. doi:10.1126/science.1250808
OppiaineEpäorgaaninen ja analyyttinen kemia
© 2014 American Association for the Advancement of Science. This is a final draft version of an article whose final and definitive form has been published by AAAS. Published in this repository with the kind permission of the publisher.
Why does cyanide not react destructively with the proximal iron center at the active site of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, an enzyme central to the biosynthesis of ethylene in plants? It has long been postulated that the cyanoformate anion, [NCCO2]–, forms and then decomposes to carbon dioxide and cyanide during this process. We have now isolated and crystallographically characterized this elusive anion as its tetraphenylphosphonium salt. Theoretical calculations show that cyanoformate has a very weak C–C bond and that it is thermodynamically stable only in low dielectric media. Solution stability studies have substantiated the latter result. We propose that cyanoformate shuttles the potentially toxic cyanide away from the low dielectric active site of ACC oxidase before breaking down in the higher dielectric medium of the cell.