Dynamic equilibration of η1-carbene and η2-alkyne moieties within an alkynylcarbene dimanganese complexElectronic supplementary information (ESI) available: details of synthesis and spectral characterisation of the new complexes. See http://www.rsc.org/suppdata/cc/b1/b104712b/

The coordination of an additional [Cp(CO)2Mn] fragment to the alkyne linkage of an alkynylcarbene complex of the type Cp(CO)2Mn=C(R')C identical to CR" yields a highly fluxional molecule, in which the [eta 1-carbene] and [eta 2-alkyne] moieties are seen to exchange rapidly on the NMR time scale.