Synthesis, characterization and toxicity of Cu(II) complexes with metformin Schiff-bases

Abstract

ABSTRACT

Copper complexes of Schiff-bases of metformin with each of salicylaldehyde (HL¹); 2,3-dihydroxybenzaldehyde (H₂L²); 2,4-dihydroxybenzaldehyde (H₂L³); 2,5-dihydroxybenzaldehyde (H₂L⁴); 3,4-dihydroxybenzaldehyde (H₂L⁵) and o-hydroxynaphthaldehyde (HL⁶) were synthesized by template reaction. The new compounds are characterized through elemental analysis, conductivity measurements, magnetic moment, IR, UV–Vis, NMR, ESR, Mass spectroscopy, TEM and molecular modeling. The complexes have square pyramidal structure with magnetic moment values of 1.96–1.81 B.M. and d_x²_−y² ground state. TGA, DTG and DTA analysis confirm the proposed stereochemistry. Thermodynamic parameters are calculated for the second and third decomposition steps. The complexes [CuL¹(H₂O)₂].2H₂O, [CuL⁴(H₂O)₂].2H₂O and [CuL⁵OH(H₂O)₂].3H₂O are evaluated for their hypoglycemic activity in alloxan-induced diabetic mice and have shown toxicity at doses of 20 and 40 mg/kg.

KEYWORDS:

• Metformin Schiff-base
• copper complexes
• spectral and thermal analysis
• toxicity effect

Disclosure statement

No potential conflict of interest was reported by the authors.