The cyanide moieties bridge between aluminium and both potassium ions, while the carboxylate groups bridge between aluminium and a single potassium cation. The Al1-C2 and Al1-O2 distances (e.g. 2.0263(18) and 1.7891( ) Å for K2[4b]2) are similar to those found in comparable complexes. The C2-N3 bond length The conversion of aluminium imides to carboxy/cyanide complex--es has been investigated by quantum chemical methods carried out using the model system [1a'] -(in which the K + cations were removed, and the NON backbone t Bu groups replaced by methyls for computational efficiency) (Scheme 5). The minimum energy reaction pathway closely resembles the previously reported and (experimentally supported) mechanism for the reaction of [VII] - with CO, both (i) in the formation of Int3 through the uptake of CO, and the formation and isomerization of a side-on bound isocyanate complex, and (ii For comparative purposes, we also examined the reactivity of gallium silylimide K [3] towards CO. Treatment of a suspension of gallium imide K [3] in benzene-d6 with CO, resulted in clean conversion to a single new product K2[(NON)Ga{O(SiPh3)}(CN)]2, K2 [5]2, over the course of six days as judged by in situ 1 H NMR spectroscopy (Scheme 6). The rate of this reaction is limited by the low solubility of the imide starting material in benzene-d6, but the cyanide-containing product K2 [5]2 can be crystallised in ca. 80% isolated yield. In the solid state K2 [5]2 adopts a dimeric structure related to that of K2[4b]2 and K2[4c]2, albeit with a metalbound siloxide, rather than a silylcarboxylate supporting ligand (Figure ). Within the dimeric framework of K2 [5]2, K + counter ions bridge between two anionic [(NON)Ga{O(SiPh3)}(CN)] -units through interactions with the Dipp and cyanide groups. The Ga1-C1 distance (2.0463(18) Å) is similar to those found in comparable complexes (e.g. {HC(MeCDippN)2}Ga( t Bu)CN, 2.028(8) Å), and the C1-N3 distance (1.148(2) Å) is statistically identical to those observed for the related aluminium cyanide complexes K2[4b]2 and K2[4c]2. The presence of the cyanide ligand is also confirmed by the presence of two closely spaced bands at 2070 and 2080 cm -1 in the IR spectrum of K2 [5]2.