Chemical methylation of germanium(II) in model aqueous solutions

Abstract

AbstractInorganic germanium(II) in micromolar concentrations was reacted with methyl iodide (CH3I) and methylcobalamin (CH3‐CoB12) at various pH values and with different salt matrices. In all experiments monomethylgermanium was the only product. The reaction with CH3‐CoB12 at pH 1 yielded approximately 1.3% of the added germanium, whereas no methylation occurred at pH 7. Reaction yields with CH3I were lowest at pH 1 in 0.1 mol dm−3 KCl (1.6%) and highest at pH 7.6 in artificial seawater (6%). For the reaction of CH3−CoB12 with germanium(II) a free‐radical mechanism is assumed, whereas methylation by CH3I is most likely an oxidative addition mechanism.