Equilibrium and DFT studies of the bi- and mononuclear complexes of 4,4′-bipiperidine with Pd(2-(2-aminoethyl)-1-methylpyrrolidine) 2+ and other biorelevant ligands

Equilibrium Studies on Pd(II)–Amine Complexes with Bio-Relevant Ligands in Reference to Their Antitumor Activity

“…The stability constant logβ 110 of [Pd(AEMP)-α-alanine] 2+ (9.74) is larger than that of [Pd(AEMP)-β-alanine] 2+ (9.10), (AEMP = 2-(2-aminoethyl)-1-methylpyrrolidine). This is the result of the extra stabilization of the 5-membered chelate rings for the α-alanine complex, as compared to the 6-membered rings for the β-alanine complex [44]. The same trend was found for the Pd(dmen) system (dmen = N,N-dimethylethylenediamine) [45].…”

“…They coordinate through both the amino acid group and carboxylate oxygen, forming stable five-membered chelate rings. The effect of chelate ring size and the basicity of the amino acid group on the stability of the formed complexes were studied [44]. The stability constant logβ 110 of [Pd(AEMP)-α-alanine] 2+ (9.74) is larger than that of [Pd(AEMP)-β-alanine] 2+ (9.10), (AEMP = 2-(2-aminoethyl)-1-methylpyrrolidine).…”

“…The formation of species 11-1, shows the ionization of the alcoholic OH group. The pK a of the ionization was determined (pK a = logβ 110 -logβ 11-1 ) as 9.60 and 9.38 for serine and threonine complexes, respectively, with [Pd(AEMP)(H 2 O) 2 ] 2+ [44]. The corresponding value for the serine complex with [Pd(pic)(H 2 O) 2 ] 2+ (where pic is 2-picolylamine) is 8.30 [34].…”

“…This may be due to the π-accepting property of the picolylamine pyridine group, which will increase the electrophilicity of the Pd (II) ion, and result in a decrease in the pK a value of the coordinated OH group. Ethanolamine forms a complex [44] with [Pd(AEMP)(H 2 O) 2 ] 2+ with a lower stability constant, at logβ 110 = 7.93. This is accounted for on the basis that there is no neutralization of the charges involved during the complex formation with ethanolamine.…”

Oxidative DNA cleavage mediated by a new unexpected [Pd(BAPP)][PdCl4] complex (BAPP = 1,4-bis(3-aminopropyl)piperazine): crystal structure, DNA binding and cytotoxic behavior

“…As reported before, under physiological conditions, the metal complexes possessing efficient DNA binding and cleavage propensities are mostly considered as drugs for cancer treatment and genomic research. [21][22][23] In the light of these facts and in continuation of our previous work on palladium amine complexes, [24][25][26][27][28][29] novel Pd(II) complex, [Pd(BAPP)][PdCl 4 ], based on 1,4-bis(3aminopropyl)piperazine ligand (BAPP) has been synthesized. The unexpected geometrical features were successfully identied by single-crystal X-ray structure analysis and different spectroscopic tools.…”