Work

Redetermination of the X-ray structure of nitroxylcobalamin: base-on nitroxylcobalamin exhibits a remarkably long Co–N(dimethylbenzimidazole) bond distance

Year: 2010

Type: article

Abstract: The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 Å, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 Å range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 Å in length, ~0.1 Å longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins.

Source: Dalton Transactions

DOI: 10.1039/c0dt00628a

Authors: Hanaa A. Hassanin, Mohamed F. El-Shahat, Serena DeBeer, Clyde A. Smith, Nicola E. Brasch

Institutions: Ain Shams University, Kent State University, Cornell University, Stanford Synchrotron Radiation Lightsource, Stanford University

Language: English

Topic: Crystal structures of chemical compounds

Subfield: Inorganic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funder: National Center for Research Resources

Award: G113944070