Azizova Asmat Nizami - The Institute of Catalysis and Inorganic Chemistry named after acad. M.Nagiyev of the National Academy of sciences Azerbaijan,e-mail: iradam@rambler.ru

Changing properties of liqands during coordinating with metals

Rzayeva Suraya Jabar – Azerbaijan Medical University research assistant, e-mail: iradam@rambler.ru

Changing properties of liqands during coordinating with metals

Gasimov Shmid Guseyn, Azerbaijan Medical University, Senior Research Fellow, e-mail: iradam@rambler.ru

Changing properties of liqands during coordinating with metals

Gasanov Khudayar Ismail, Azerbaijan Medical University, Doctor of chemistry, professor e-mail: iradam@rambler.ru

Changing properties of liqands during coordinating with metals

CHANGING PROPERTIES OF LIQANDS DURING COORDINATING WITH METALS

It is known that sulfur- and nitrogen-containing ligands have high tendency to form complexes with platinum (II) and palladium (II). Synthesis of mixedligands complex compounds of platinum (II) with tetramethylethylenediamine – (CH₃)₂N (CH₂CH₂) N (CH₃)₂ (tetmen) and ethylenditiodiacetic acid HCOOS (CH₂CH₂) SCOOH (HSSH), as well as determining of dependence of the properties of complexes on the nature of central atoms presents great interest for biocoordination chemistry.

In the subacid conditions the action of an equimolar amount tetmen, HSSH and [Pd (NH₃)₄] Cl had been obtained a pale yellow crystalline substance – [Pd (tetmen) (HSSH)] Cl₂•3H₂O. The composition and structure of the synthesized complexes studied by modern physico-chemical methods. The resulting material is soluble and have a low-grade acidic properties. At the potentiometric titration of suspension [Pd (tetmen) (HSSH)] Cl₂•3H₂O against the background of 0.3M NaNO₃ there is a jump in the titration curve in the area of two equivalents of added alkali, which corresponds to simultaneous titration of the two carboxyl groups. In the acidic medium at the same time there is a protonation of both atoms of nitrogen.

Determination of acid dissociation constants of the complex [Pd (tetmen) (HSSH)]Cl₂•3H₂O was carried out on the basis of titration data of solutions with concentration of 1.0•10^-3 mol/l on the background of 0.2 m KCl, taken into account simultaneously titration of the two hydrogen ions. The infrared spectrum of the complex [Pd (tetmen) (HSSH)] Cl₂ • 3H₂Ohas been shot in the  areas 200–500 and 1000–2000 cm^-1.

In the IR spectrum of the complex absorption bands with frequency 349, 356 and 422 and 430 cm^-1 had been attributed respectively to the chemical bonds of Pd-S and Pd-N. Two absorption bands for single links indicate their cis-location. Other observed three absorption bands in 1716, 1728 and 1770 cm^-1 have a varying intensity, which are assigned to n_СООН protonated carboxyl group.

It should be noted that the complex – [Pd (tetmen) (HSSH)] Cl₂ • 3H₂O in alkaline medium deprotonation of the carboxyl group does not occur, i.e. there is no coordination carboxyl group to the central atom.

In the IR spectrum of the crystalline hydrate absorption bands had been present, which can be attributed to n_ОН –3420 cm^-1 and d_ОН –1640 cm^-1 of the crystallization water.

Thermal analysis of the complex shows that at the temperatures above 1400°C three water molecules are segrerate. On the thermogram of anhydrous substance on the DTA curve disappears endothermic peak associated with the detachment of water from the crystalline. It should be noted that if the anhydrous product to sustain in a desiccator over water, within a day the substance absorbs two molecules of water again.

The obtained complex – [Pd (tetmen) (HSSH)]Cl₂•3HO with cis-structure has radioprotective and moderate psychoactive properties.

Studies have shown that regardless of the nature of the central atom, it can get complex with a given structure depending on the nature of the ligand.