Synthesis and biological activity of trinuclear seven-coordinated tin(IV) complexes derived from tridentate ligands and trimesic acid

Abstract

The synthesis of trinuclear Sn(IV) complexes 5a–h – prepared in a one-pot reaction of 2-amino-4-R-phenol (R=H, Me, Cl, NO₂), 2-pyridine-carboxaldehyde, 1,3,5-benzenetricarboxylic acid (trimesic acid, H₃BTC), and dibutyl and dioctyltin oxides – is described. These compounds were characterized by elemental analysis, mass spectrometry, IR, and multinuclear NMR spectroscopy. The structures of 5a and 5b were also determined by single-crystal X-ray analysis. The trinuclear tin system is formed by bridges through the carboxylate moieties. The metal centers are seven-coordinate and the coordination polyhedron of tin can be depicted as distorted pentagonal-bipyramidal (PBP), where the equatorial plane consists of three oxygens and two nitrogens and the organic groups occupy the axial positions. The work presented here combines the useful properties of Schiff bases and H₃BTC ligands in the formation of organotin(IV) complexes, and investigates the likely antioxidant (DPPH and TBARS) and anti-inflammatory activity (TPA) of the new substances.

Graphical abstract

Keywords:

• Trinuclear diorganotin(IV)
• Carboxylate
• ¹¹⁹Sn NMR
• X-ray diffraction
• Seven-coordinate
• Biological activity

Acknowledgements

The authors are grateful for the financial support from DGAPA (IN204814 and IN200911) and thank Rocío Patiño, María de la Paz Orta Pérez, Alejandra Núñez Pineda, Javier Pérez, and Luis Velasco for the IR, elemental analyses, and mass spectrometry technical support, as well as Claudia Rivera Cerecedo and Héctor Malagón Rivero, from Instituto de Fisiología Celular, UNAM. Thanks are also due to Juan Rolando Vázquez Miranda from Facultad de Química, UNAM, for conductance measurements.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the DGAPA [grant numbers IN204814 and IN200911].