NBO calculations provide further detail on the changes to electronic structure as CH3CN is doubly deprotonated (see Table The CH2CN 1 H NMR signal integrating to 2H can be found at δH = 1.68 ppm which is downfield of the corresponding resonance for CH3CN (δH = 0.69 ppm in toluene-[D8]). 13 C{ 1 H} NMR measurements recorded at -40 °C support the assignment of the intermediate as an N-coordinated (3b) rather than Ccoordinated (3b') isomer (δC(CH2CN) = 5.3 ppm, DFT: 3b: 7.9 ppm cf. for 3b': -0.9 ppm).This assignment is further supported by IR spectroscopic analysis: 3b shows a strong band at 2067 cm -1