@article{Kozachkova_Tsaryk_Pekhnyo_2019, title={INTERACTION OF CIS-Pd(NH3)2Cl2 WITH DIPHOSPHONIC ACIDS IN SOLUTIONS AT PHYSIOLOGICAL CHLORIDE-IONS CONCENTRATION}, volume={85}, url={https://ucj.org.ua/index.php/journal/article/view/98}, DOI={10.33609/0041-6045.85.11.2019.3-14}, abstractNote={<p>The complex formation of cis-Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub> with 1-hydroxyethylidene-1,1-diphosphonic (HEDP, H<sub>4</sub>L1), 3-amino-1-hydroxypropylidene-1,1-diphosphonic (AHPrDP, H<sub>4</sub>L2), and 1-aminopropylidene-1,1-diphosphonic (APrDP, H<sub>4</sub>L3) acids in aqueous solutions with the concentration <em>C</em><sub>KCl </sub>= 0.15 mol/L, which corresponds to the concentration of chloride ions in the intercellular fluid, has been studied by spectrophotometry and pH potentiometry. The results of studying the interaction between cis-Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub> and diphosphonic acids have been interpreted taking into account the equilibrium concentration distribution of complexes forming in Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub> solutions at a chloride ion concentration of 0.15 mol/L. It has been found that when Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub> is dissolved in 0.15 mol/L KCl, ammonia molecules are substituted by chloride ions and a water molecule in the pH range of 2 – 4 to form chloro-aqua complexes [PdCl<sub>4</sub>]<sup>2-</sup> and [PdCl<sub>3</sub>(H<sub>2</sub>O)]<sup>-</sup>.</p> <p>In the case of complex formation of Pd(II) chloro-aqua complexes with HEDP and AHPrDP, complexes with [Pd;2OPO<sub>3</sub>;2Cl] chromophore with bidentate coordination of ligands by two oxygen atoms of phosphonic groups are formed in the acidic pH range. At pH &gt; 5, a [Pd(L1)(NH<sub>3</sub>)<sub>2</sub>]<sup>2–</sup> complex (lgβ = 30.55(5)) is formed in the cis-Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2 </sub>: HEDP = 1:1 system, and at pH &gt; 6, a [Pd(HL2)(NH<sub>3</sub>)<sub>2</sub>]<sup>-</sup> complex (lgβ = 40.29(2)) is formed in the cis-Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2 </sub>: AHPrDP = 1:1 sys-tem. The formation of complexes with [Pd;2OPO<sub>3</sub>;2N<sub>amine</sub>] chromophore takes place with the displacement of chloride ions from the coordination sphere of complexes with [Pd;2OPO<sub>3</sub>;2Cl] chromophore by ammonia molecules.</p> <p>In the system cis-Pd(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2 </sub>: APrDP = 1:1, the ligand is coordinated to Pd(II) in a bidentate fashion by the nitrogen atoms of the amine group and oxygen atoms of the phosphonic group to form a [Pd(H<sub>2</sub>L3)Cl<sub>2</sub>]<sup>2–</sup> complex with [Pd;N<sub>amine</sub>;OPO<sub>3</sub>;2Cl] chromophore in the acidic pH range. When pH is increased to 5 and then to 7, a sequential substitution of chloride ions by ammonia molecules takes place to form a [Pd(HL3)(NH<sub>3</sub>)Cl]<sup>2–</sup> complex (lgβ = 38.84(4)) with [Pd;2N<sub>amine</sub>;OPO<sub>3</sub>;Cl] chromophore and a &nbsp;[Pd(HL3)(NH<sub>3</sub>)<sub>2</sub>]<sup>–</sup> complex (lgβ = 43.14(2)) and [Pd(L3)(NH<sub>3</sub>)<sub>2</sub>]<sup>2–</sup> complex (lgβ = 34.91(2)) with [Pd;3N<sub>amine</sub>;OPO<sub>3</sub>] &nbsp;chromophore.</p&gt;}, number={11}, journal={Ukrainian Chemistry Journal}, author={Kozachkova, Oleksandra and Tsaryk , Nataliia and Pekhnyo, Vasyl}, year={2019}, month={Dec.}, pages={3-14} }