The reaction of K[1a] with CO in benzene unfortunately leads to the formation of an inseparable mixture of poorly soluble products. The analogous reaction of the more soluble imide K[1b] initially also produces several products; however over the course of two weeks, conversion to a single major compound, K2[(NON)Al{O2C(Si t BuPh2)}(CN)]2, K2[4b]2, is observed by 1 H NMR spectroscopy (Scheme 4). This compound could be crystallised only in relatively low yields (10-15%) due to its high solubility, but this did allow the molecular structure in the solid state to be determined, revealing the formation of cyano and silylcarboxylate ligands (Figure ). Moreover, consistent with the solid-state structure, the 13 C{ 1 H} NMR spectrum of K2[4b]2 features a signal at dC = 187.7 ppm associated with a silylcarboxylate group. NMR spectroscopy (Scheme 4). This compound could also be crystallised, in this case in ca. 35 % isolated yield. The molecular structure in the solid state was determined crystallographically (Figure ), and K2[4c]2 was also characterised by standard spectroscopic techniques and elemental analysis. The IR spectrum shows diagnostic bands at 2126, 1640, 1587, 1486 and 1417 cm -1 . The band at 2126 cm -1 is weak and corresponds to the CN stretch; the remaining four bands are stronger and correspond to the symmetric and asymmetric stretching modes of the carboxylate C-O bonds, and two vibrations of the ligand backbone. In a similiar fashion to K2[4b]2, the C NMR spectrum of K2[4c]2 features a signal at dC = 189.6 ppm assigned to the silylcarboxylate group.