The name/synonym for ligand HEC (curated from ChEBI, PubChem, and PDB databases):

1FERROHEME C(2-)
2HEME C
3{3,3'-[3,7,12,17-TETRAMETHYL-8,13-BIS(1-SULFANYLETHYL)PORPHYRIN-2,18-DIYL-KAPPA(4)N(21),N(22),N(23),N(24)]DIPROPANOATO(4-)}FERRATE(2-)
43,7,12,17-TETRAMETHYL-8,13-DIVINYL-2,18-PORPHINEDIPROPIONIC ACID