3-Ferrocenyl-estra-1,3,5 (10)-triene-17-one: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, DFT Studies, and Its Binding to Human Serum Albumin Studied through Fluorescence Quenching and In Silico Docking Studies

3-ferrocenyl-estra-1,3,5 (10)-triene-17-one (2), [Fe(C5H5)(C24H25O3)], crystallizes in the monoclinic space group C2. The cyclopentadienyl (Cp) rings adopt a nearly eclipsed conformation, and the Cp plane is tilted by 87.66° with respect to the substituted phenyl plane. An average Fe-C(Cp) bond length of 2.040(13) Å was determined, similar to the one reported for ferrocene. Hirshfeld surfaces and two-dimensional fingerprint plots were generated to analyze weak intermolecular C-H···π and C-H···O interactions. Density functional theory studies revealed a 1.15 kcal/mol rotational barrier for the C3-O1 single bound. Fluorescence quenching studies and in silico docking studies suggest that human serum albumin forms a complex with 2 via a static mechanism dominated by van der Waals interactions and hydrogen bonding interactions.