Onur Sahin

Synthesis and characterization of transition metal-vitamin B13 complexes mixed with a co-vitamin

The synthesis and structural characterization of mixed vitamin-metal complexes are reported. A complex bearing two vitamins (B3 and B13) on the same metal centre, nicotinamide(orotato)nickel(II) pentahydrate, has been prepared and characterised by single-crystal X-ray diffraction methods. A complex of Cr(III) with vitamins C and B13, bis(ascorbato)orotatochromium(III) dihydrate, has been isolated and its nature investigated by means IR, 13C NMR, API-ES and thermogravimetric measurements. Theoretical calculations have been performed to propose a structure in accord with results obtained.

Seven-, eight-, and ten-coordinated cerium(III) with highly connective pyridine-2,4,6-tricarboxylate, oxalate, and glycine ligands

Two new 3-D Ce(III) coordination polymers, [Ce1.3(PTA)2(Oxa)2(Gly)(H2O)2]·(Gly)4H2O (1) and [Ce2.6(PTA)4(Oxa)2(H2O)10]·(MeOH)7H2O (2) (PTA = 2,4,6-pyridinetricarboxylate, oxa = oxalate and Gly = glycine), were synthesized. The oxalate in 1 and 2, generated in situ from the cleavage and chemical rearrangement of PTAH3, assembled into mixed-ligand networks to generate 3-D frameworks. Single crystal analysis reveals that in both complexes, Ce(III) shows coordination numbers of 7 and 10 in 1 and 8 and 10 in 2. PTA adopts four kinds of coordination modes. These complexes were further characterized using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.

Synthesis and characterization of four novel palladium(II) and platinum(II) complexes with 1-(2-aminoethyl)pyrrolidine, diclofenac and mefenamic acid: In vitro effect of these complexes on human serum paraoxanase1 activity

In this study, the effects of four novel mononuclear palladium(II) and platinum(II) complexes on the activity of human serum paraoxanase1 were examined. First, four novel mononuclear palladium(II) and platinum(II) complexes were synthesized with a nitrogen donor ligand 1‐(2‐aminoethyl)pyrrolidine and nonsteroidal anti‐inflammatory drugs diclofenac, mefenamic acid. These complexes were characterized by spectroscopic, thermal, and elemental analyses. The crystal structures of complex [Pd(2‐amepyr)2](dicl)2 1 and [Pd(2‐amepyr)2](mef)2 3 were determined by X‐ray crystallography. Then, paraoxonase1 enzyme was purified from human serum. The effects of these complexes on enzyme were evaluated in vitro. The complexes consist of the cationic unit and the counterions. The diclofenac and mefenamic acid acted as a counterion in the complexes. It was observed that all the complexes were stable up to high temperatures. These complexes, even at low doses, inhibited the activity of the enzyme with different inhibition mechanisms.