The chemical shift difference between the two solvents Δδ can be converted into hydrogen bond acidity (ANMR) for a quantitative assessment of IMHB. Literature correlations provided threshold values associated with HBD participation in an IMHB and/or polarity shielding. An ANMR ≥ 1 indicates the absence of I B, while values below suggest strong I B 38 AS4 exhibits overall ANMR values for the NH beyond the threshold ≤ 1 , Figure , graph), indicating the presence of a flexible intermolecular hydrogen bond network likely mediated by the ferrocene moiety, which results in more shielded amides. Specifically, among the two amides adjacent to the ferrocene core, the N( )-H appears to engage more significantly in IMHB compared to N(3)-H, as indicated by slightly lower ANMR values for N(4)-H (0.11 vs 0.13). This might be due to a hydrogen bonding pattern that resembles that found in heterochiral peptides through the formation of an antiparallel β-sheet-like structure. According to this speculation, both N(3)-H and N(4)-H seem to participate in a seven-membered ring (Figure , in red), with N(4)-H accessing an additional conformation where the oxygen from the PEG group might serve as a hydrogen bond acceptor through a stabilised tenmembered ring (Figure , in green). While highly indicative for conformational studies, the ANMR values however reflect changes between solvents, which in turn indicate shifts in the solution conformational ensembles. For large, flexible molecules like PROTACs, the conformational ensembles can vary significantly between different solvents. These differences may include variations in the number of selected conformers, their population distributions, and the specific conformations adopted. Consequently, ANMR values can be affected by factors beyond IMHB, reflecting more extensive alterations in the molecule's overall conformational landscape.