Five organotin complexes derived from hydroxycinnamic acid ligands: Synthesis, structure, in vitro cytostatic activity and binding interaction with BSA

Five new organotin(IV) hydroxycinnamates, [(Me3Sn)HL1](n) (1), [(Ph3Sn)(2)L-1](n) (2), (n-Bu2Sn)(HL1)(2) (3), [(Me3Sn)HL2](n) (4), [(Ph3Sn)(2)L-2](n) (5), have been synthesized by the reactions of R3SnCl (R = Me, Ph) or n-Bu2SnO with the corresponding hydroxycinnamic acid proligands [H2L1 = 4-OH-3-CH3OC6H3CH=CHCOOH, ferulic acid; H2L2 = 4-OH-3,5-(CH3O)(2)C6H2CH= CHCOOH, sinapic acid]. All the complexes have been characterized by X-ray diffraction analysis, elemental analysis, NMR (H-1, C-13 and Sn-119), FT-IR, and PXRD (Powder X-ray diffraction). The structural analyses reveal that complexes 1, 2 and 5 display 1D infinite zig-zag chain structure, in which the 1D chains are further linked into a 3D supramolecular structure through intermolecular O-H center dot center dot center dot O interactions (for complex 1) or C-H center dot center dot center dot O interactions (for complex 5). Complex 3 presents mononuclear tin monomer and further constructs 2D planar supramolecular structure through intermolecular O-H center dot center dot center dot O interactions. Complex 4 displays 1D righthanded helical chain and further connects into a 3D supramolecular architecture through intermolecular O-H center dot center dot center dot O interactions. Furthermore, the in vitro cytostatic activity of complexes 1-5 was preliminarily evaluated by MTT method, and the results showed that complexes 2, 3 and 5 exhibited high cytostatic activity. The protein-binding properties of complexes 2, 3 and 5 were also investigated, which indicated these complexes could quench the intrinsic fluorescence of BSA in a static way. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Five new organotin(IV) hydroxycinnamates were synthesized and characterized by various analyses, revealing different supramolecular structures and cytostatic activities. Complexes 2, 3, and 5 exhibited high cytostatic activity and could quench the intrinsic fluorescence of BSA in a static manner.