Abstract:
In this research oxovanadium complexes and di oxovanadium complexes (C1-C15)
and ligands (L1-L16), specifically, organic ligands considered to be of biological
importance, as insulin mimics. They were synthesized, and divided in four groups:
vanadium salts with amino acids, carboxylic acids, thiosemicarbazone, 1.10
phenanthoroline, 3-Hydroxypyridine and Schiff-base ligands. The complexes were
characterized by conductivity measurements; magnetic susceptibility, UV-Vis, IR,
thermal gravimetric analysis TGA,
III
1
H and
13
C NMR.The molecular structure of the
complexes (C1- C15) were confirmed using the DFT calculation to obtain the
optimized geometries using the Gaussian 09 program at the B3LYP/LANL2DZ
level of theory. The vanadium atoms in the complexes were coordinated in
different distorted geometries with ligands (L1- L16), acting as a bi-dentate and
tridentate ligands through the amino nitrogen atoms, sulfur atom, phenol oxygen
atom and carboxylate oxygen atom.
The total energies for the highest occupied molecular orbital (HOMO) energies,
the lowest unoccupied molecular orbital (LUMO) energies and the dipole moment
for the ligands (L1-L16), and their complexes (C1-C15), were calculated, It was
found that the more negative value of total energy of the complexes than that of
free ligands indicates their extra stability polarity, much larger enhance than those
of free ligands.
As vanadium compounds insulin sensitivity and act as insulin mimetic and has
anti-diabetic effects, complexes of C1, C6, C10, C13 were further tested on rats
after they had been injected by streptozotocin, that causes a type 2 diabetes. In this
study intra-peritoneal administration active anti-diabetic organic vanadium
complexes. After four weeks of complexes treatment, the result showed significant hyperglycemia improvement indicating that vanadium complexes had anti-diabetic
and insulin-sensitizing effects on the diabetic rats.
