Magnesium(II), calcium(II), chromium(III), zinc(II), copper(II), and selenium(IV) sitagliptin (STG) complexes-with the general formulas [Mg(STG)2(Cl)2]·6H2O, [Ca(STG)2(Cl)2], [Cr(STG)2(Cl)2]Cl.6H2O, [Zn(STG)2(Cl)2], [Cu(STG)2(Cl)2]·2H2O, and [Se(STG)2(Cl)2]Cl2, respectively-were designed and synthesized by the chemical reactions between metal(II, III, and IV) chloride salts with an STG ligand in situ methanol solvent in a 1:2 stoichiometric ratio (metal:ligand). Tentative structures of the complexes were proposed based on elemental analysis, molar conductance, magnetic moments, thermogravimetric analysis, and spectral (infrared, electronic, and 1H NMR) data. The particle size and morphological investigation were checked on the bases of scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction analyses. All the Mg2+, Ca2+, Cr3+, Zn2+, Cu2+, and Se4+ complexes were found to be six-coordinated, wherein the STG ligands act as bidentate chelating agents. This study demonstrates that pancreatic tissues are affected by the induction of experimental diabetes mellitus and clarifies the potential of the synthesized STG complexes, which was found to more significantly improve insulin secretion and the pancreatic and glycometabolic complications of diabetic rats than STG alone.
Keywords: STZ; complexes; diabetes; morphology; sitagliptin; spectroscopic.