The nature of the ligation of N-methylformamide (NMF) to the metal sites of FeMoco has been investigated. The IR spectrum of FeMoco in NMF shows an intense band at 1600 cm-1 which we assign to the v(CO) stretch of ligated NMF. This frequency is characteristic of N-deprotonated amide ligands, indicating that NMF ligation to FeMoco is predominantly through nitrogen. Hence NMF behaves as an anionic ligand. The importance of the amide functionality for FeMoco extraction has been further examined and a new extracting agent, 2-pyrrolidinone, has been employed. We hypothesize that, in the MoFe-protein, the primary coordination of the cofactor is via deprotonated backbone amide ligands.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry