Reactions of isonitriles with [Fe3(CO)12] and [Ru3(CO)12] monitored by electrospray mass spectrometry: structural characterisation of [Fe3(CO)10(CNPh)2] and [Ru4(CO)11(μ3-η2-CNPh)2(CNPh)]

The reactions of [Fe3(CO)12] or [Ru3(CO)12] with RNC (R=Ph, C6H4OMe-p or CH2SO2C6H4Me-p) have been investigated using electrospray mass spectrometry. Species arising from substitution of up to six ligands were detected for [Fe3(CO)12], but the higher-substituted compounds were too unstable to be isolated. The crystal structure of [Fe3(CO)10(CNPh)2] was determined at 150 and 298 K to show that both isonitrile ligands were trans to each other on the same Fe atom. For [Ru3(CO)12] substitution of up to three COs was found, together with the formation of higher-nuclearity clusters. [Ru4(CO)11(CNPh)3] was structurally characterised and has a spiked-triangular Ru4 core with two of the CNPh ligands coordinated in an unusual μ3-η2 mode.