Stabilizing intramolecular cobalt-imidazole coordination with a remote methyl group in the backbone of a cofactor B12-protein modelElectronic supplementary information (ESI) available: Experimental details. See DOI: 10.1039/c8dt01298a

• Main Authors: Sonnay, Marjorie, Zelder, Felix
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c8dt01298a

This communication describes the stabilizing effect (ΔΔ G ° = −4 kJ mol −1 ) of a remote methyl group in the backbone of a cobalamin-enzyme mimic on intramolecular imidazole-cobalt coordination. For this purpose, two B 12 derivatives with an appended imidazole base were synthesized and analysed with spectrophotometric pH titrations. Qualitative conformation analysis of the backbone structure suggests that a thermodynamically unfavoured gauche interaction in the base-off form of a model containing an ( R )-configured CH 3 group at position C176 of the linker between the corrin ring and the terminal imidazole ligand steers the base toward cobalt coordination. This communication describes the stabilizing effect of a remote methyl group in the backbone of a cobalamin-protein mimic on intramolecular imidazole-cobalt coordination.