Synthesis, spectral, thermal and insulin-enhancing properties of oxovanadium(IV) complexes of metformin Schiff-bases

• Published in: Journal of thermal analysis and calorimetry 2017-05, Vol.128 (2), p.957-969
• Main Authors: Mahmoud, Marwa A., Zaitone, Sawsan A., Ammar, Alaa M., Sallam, Shehab A.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemical analysis; Chemical synthesis; Chemistry; Chemistry and Materials Science; Differential thermal analysis; Electric properties; Infrared spectroscopy; Inorganic Chemistry; Insulin; Magnetic moments; Mass spectrometry; Measurement Science and Instrumentation; Metformin; Physical Chemistry; Polymer Sciences; Stereochemistry; Thermal decomposition; Vanadyl ions
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-016-6018-1

A series of VO 2+ complexes of Schiff-bases of metformin with each of salicylaldehyde (HL 1 ); 2,3-dihydroxybenzaldehyde (H 2 L 2 ); 2,4-dihydroxybenzaldehyde (H 2 L 3 ); 2,5-dihydroxybenzaldehyde (H 2 L 4 ); 3,4-dihydroxybenzaldehyde (H 2 L 5 ); and 2-hydroxynaphthaldehyde (HL 6 ) were synthesized by template reaction. The new compounds are characterized through elemental analysis, conductivity measurements, magnetic moment, IR, UV–Vis, ESR and mass spectroscopy. The complexes have square pyramidal structure with μ values of pentacoordinated vanadyl ion. TG, DTG and DTA confirm the proposed stereochemistry, and a mechanism of thermal decomposition was suggested. Mice treated with the complexes [VOL 1 H 2 O]·1½H 2 O and [VOHL 4 H 2 O]·2H 2 O showed glucose-lowering effect of 59.31, 58.79% (20 mg kg −1 ) and 64.98, 74.8% (40 mg kg −1 ) compared to metformin.