Figure 4.

Selected spectral and crystallographic data of the metallacyclobutadiene subunits of 17 and 18; the insert shows the satellite peaks for the Cα/Cα′ atoms of 18.

Selected spectral and crystallographic data of the metallacyclobutadiene subunits of 17 and 18; the insert shows the satellite peaks for the Cα/Cα′ atoms of 18.