Synthesis, structure and antidiabetic activity of chromium(III) complexes of metformin Schiff-bases

A series of Cr3+ complexes with 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 2-hydroxynaphthaldehyde (HL6) were synthesized by template reaction. The new compounds were characterized through elemental analysis, conductivity and magnetic moment measurements, IR, UV Vis., NMR and mass spectroscopy. The complexes have octahedral structure with mu value of hexacoordinated chromium ion. TGA, DTG and DTA analysis confirm the proposed stereochemistry and a mechanism for thermal decomposition was proposed. Thermodynamic parameters are calculated for the second and third decomposition steps. [(CrLCI)-C-4(H2O)(2)].3H(2)O and [CrL5Cl(H2O)(2)].21/2H(2)O were able to produce significant decreases in the blood glucose level. (C) 2015 Elsevier B.V. All rights reserved.