Fig. 2. ESI-mass spectrometry signals (left side) and 1H-NMR spectra (right side) of the precursor Fe(L1)2 (bottom) and the macrocyclized Fe(L1)2-c (top). The acetylene H-atoms and their signal are highlighted by dark yellow circles. The reduction of the mass by 2 m/z units and the disappearance of the acetylene H-atoms in the NMR spectrum indicate the successful macrocyclization.
