With a series of keteniminyl anions in hand, we proceeded to investigate their structural and spectroscopic properties. Our primary focus was to determine whether these species are more accurately described as keteniminyl anions (3) or as ynamides (3'), with the metal preferentially binding to the nitrogen end. (Scheme 1). In THF solution, the keteniminyl anions 3 exhibit signals at approx. 40 ppm in the C{ 1 H} NMR spectrum corresponding to the CCN carbon atom (Table ). This signal is significantly upfield shifted compared to neutral ketenimines (e.g. 76.2 ppm for (iPr)2C=C=NiPr) and ynamines (e.g. 73.0 ppm for Ph-C≡C-N(iPr)CO2CH2CHCH2), arguing for a lone pair at this carbon atom. Within the series of keteniminyl anions 3a-3e, this signal exhibits only minor shifts, with a tendency toward higher fields as the donor ability of the nitrogen substituents increases.