• Chesman, Anthony
• Batten, Stuart

Abstract

In this work the nucleophilic addition of water and methanol to the dicyanonitrosomethanide anion (dcnm, [C(CN)2(NO)]-) in the absence of the usual transition metal promoters was investigated. Experimentally it was shown that a quantitative conversion of the dcnm anion to carbamoylcyanonitrosomethanide (ccnm, [C(CN)(CONH2)(NO)]-) by the addition of 1 equiv of water to a nitrile group is complete in 48 h at 100 A?C, or in 1.5 h at 150 A?C when the reaction is conducted in a microwave reactor. Attempts to add a second equivalent of water to the anion failed with thermal degradation of the anion occurring at 200 A?C. Ab initio calculations show that the reaction proceeds via three distinct transition states: (1) the transfer of a proton from a water molecule to the nitrile group, (2) the subsequent attack of the generated hydroxide anion on the carbon atom of the nitrile group, and (3) a rapid proton transfer to form a carbamoyl group. The attacking water molecule is shown to be a stronger proton donor when modeled as part of a hydrogen-bonded three water molecule chain, leading to a significant reduction in the reaction barrier. Only the anti-ccnm anion is formed in the reaction. There is a high-energy barrier to the formation of the syn isomer by the rotation of the nitroso group.

Topics

• impedance spectroscopy
• Carbon
• Hydrogen
• nitrile