Synthesis, x-ray structure, Hirshfeld analysis and antidiabetic assessment of a novel μ-oxalato Cu(II)-pyrazolone complex

An unexpected dinuclear [(Cu(PP)(H2O))2-μ-ox]·3H2O complex; CuPPO, comprising a bridged oxa-late anion (ox2-) and 5-methyl-4-nitro-3-oxo-2-(pyridin-2-yl)-2,3-dihydropyrazol-1-ide (PP) as ligands was synthesized by reaction of 4-(2-(3-methyl-5-oxo-1-(pyridin-2-yl)- 1,5-dihydro-4H-pyrazol-4-ylidene)hydrazinyl) benzenesulfonamide (HPPS) and Cu(NO3)2·3H2O in presence of nitric acid and ethanol as solvent. An unexpected oxidation of ethanol to oxalate anion in addition to hydrolysis of HPPS with subsequent nitration occurred leading to formation of the PP ligand which acting as a bidentate NN-chelate. The new complex is characterized by elemental analy-sis, FTIR analysis, and single crystal X-ray diffraction. In this dinuclear complex, there are two crys-tallographically independent penta-coordinated Cu(II) centers with square pyramidal coordination geometry. The variety of intermolecular interactions affecting the molecular packing of the Cu(II) complex were decomposed by Hirshfeld analysis. The most significant interactions are O···H (33.4%) and C···H (10.7%). In addition, enrichment ratios greater than 1 for O···H, O···N, O···C, H···H, N···C, and C···C revealed high predisposition of each atom pair to interact. CuPPO was evaluated for its in vitro anti-diabetic activity against α-glucosidase, α-amylase and glucose uptake and the re-sults are compared with acarbose and berberine as reference anti-diabetic drugs. CuPPO showed ex-cellent inhibitory potential against α-glucosidase with IC50 values 6.52± 0.33 µM. Also, CuPPO showed higher glucose uptake compared to berberine with EC50 values of 19.03±0.12 µM.