Bovine serum albumin interactive one dimensional hexanuclear manganese(iii) complex: synthesis, structure, binding and molecular docking studies

Abstract

The reaction of MeO-salox (4-methoxy salicylaldehyde-oxime) with Mn(OAc)₂·4H₂O in a 1 : 1 molar ratio in methanol medium and in the presence of tetrabutylammonium hydroxide yields the hexanuclear complex [Mn₆O₂(4-MeO-salox)₆(N₃)₂(MeOH)₂(H₂O)₂·2H₂O]_n (1). Single crystal X-ray diffraction reveals that complex 1 adopts a 1D chain network facilitated by two EE-azido bridges. BSA binding studies reveal that complex 1 causes fluorescence quenching of BSA through both static and dynamic mechanisms. A 1 : 1 binding mode is established through a Benesi–Hildebrand plot with an intrinsic binding constant of (3.40 ± 0.01) × 10⁴ M⁻¹. The circular dichroism studies indicate variation of the secondary structure of BSA upon binding with complex 1. The site-selective binding and molecular docking studies reveal the probable binding site of complex 1 is at the mouth of site I in subdomain IIA of BSA.