... More precisely regarding “M−C⋮C” units, Manna et al. ... 1a,d,25 For the 1,4-bromo-, 4-tolyl-, 1,4-methoxy-, and 1,4-aminophenylethynyl ligands, the triple-bond lengths are in the expected range (ie ... formula, C 44 H 43 BrP 2 Fe, C 45 H 46 P 2 Fe, C 45 H 46 OP 2 Fe, C 44 H 45 NP 2 ...