Design, synthesis, spectroscopic and structural characterization of a new pyrimidine derived Schiff-base ligand and its Co^III, Ni^II and Cu^II complexes: evaluation of their photocatalytic and antidiabetic activities

In this study, a new pyrimidine containing Schiff base ligand (E)-4,6-dimethyl-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)pyrimidine (DMHyP2AcPy) (L) and it’s three metal ion complexes [Co^III(L⁻)₂](NO₃) (1), [Ni^II(L)₂](ClO₄)₂·2H₂O (2) and [Cu^IIL(NO₃)₂] (3), have been synthesized and characterized. 1, 2, and 3 have been found to behave as (1:1), (1:2) and nonelectrolytes, respectively. Single crystal X-ray diffraction studies have identified an NNN tridentate coordination mode of L, coordinates to the metal centre through the pyrimidine nitrogen, azomethine nitrogen and pyridyl nitrogen atoms, resulting in octahedral complexes for 1 and 2, and a square pyramidal coordination, involving two monodentate nitrate anions for 3. The photocatalytic activities of all the reported compounds have been investigated by UV–Vis spectroscopic technique and it has been found that all the three complexes possess effective photocatalytic activities (86.7%, 84.5%, 81.9% and 49.6% respectively for 1, 2, 3 and L) towards degradation of Methylene-Blue (MB) dye. Assessment of the compounds as anti-diabetic agents has been conducted in alloxan-induced diabetic mice model. The lowering of blood glucose level in diabetic mice with 3 showed the highest potential as an anti-diabetic agent amongst all the three reported complexes, which mitigates through modulation of BCL-2 protein expression that could regulate ROS initiated beta cell energetics and overall glucose homeostasis. Thus, 3 could serve as a potent anti-diabetic drug candidate in therapeutic management of diabetes globally.