An Imidazopyridine‐Based fac ‐Tricarbonyl Re(I) Complex: Synthesis, Characterization and BSA Binding Insights via Molecular Docking

ABSTRACT

Organometallic fac‐ tricarbonyl rhenium(I) complexes have attracted considerable attention owing to their potential applications in bioimaging, diagnosis and therapy. Herein, a novel organometallic complex, fac ‐[Re ^I ( L )(CO)₃Br] ( 1 ), containing the heterocyclic ligand 2‐(pyridin‐2‐yl)imidazo[1,2‐a]pyridine ( L ), was synthesized and characterized via various analytical, spectroscopic and theoretical investigations. Additionally, single‐crystal x‐ray diffraction analysis revealed a distorted octahedral coordination environment around the Re(I) centre. Packing illustration of complex 1 shows weak hydrogen‐bonding, π···π stacking along with van der Waals interactions between aromatic rings. Furthermore, a quantitative assessment of various kinds of intermolecular interactions (H···H, O···H, C···H and Br···H etc.) as well as their 2D fingerprint plot was examined by Hirshfeld surface analysis. Electrochemical studies afforded Re ^I /Re ^II couple with an E _1/2 value of 0.40 V (for 1 ) versus Ag/AgCl. Interaction of complex 1 with bovine serum albumin (BSA) established by UV–visible and fluorescence studies, indicating a static interaction. FRET analysis further estimated a donor (BSA)–acceptor (complex 1 ) distance of 3.55 nm, while molecular docking studies revealed a favourable binding energy of −5.12 kcal mol ⁻¹ near Asn44 and Lys20. The interaction distances of 1.9–2.9 Å confirmed significant interactions of BSA and complex 1 and demonstrated its potential for future therapeutic applications.