Ducilon et al. later confirmed these predictions by synthesizing and characterizing two neptunyl-pyrrophen complexes (NpO2L1 and NpO2L2). Single-crystal X-ray diffraction revealed near-linear O=Np=O bond angles and Np=O bond lengths consistent with theoretical expectations. Raman spectroscopy further supported the presence of Np(VI). Their study also showed how ligand modifications influence complex stability. The methyl-substituted ligand