Amino acid complexes of palladium(II). 1. NMR study of the reactions of the diaqua(ethylenediamine)palladium(II) cation with ammonia, betaine, and the amino acids +NH3(CH2)nCO2 - (n = 1-3)

Appleton T.G., Bailey A.J., Bedgood Jr. D.R. and Hall J.R. (1994) Amino acid complexes of palladium(II). 1. NMR study of the reactions of the diaqua(ethylenediamine)palladium(II) cation with ammonia, betaine, and the amino acids +NH3(CH2)nCO2 - (n = 1-3). Inorganic Chemistry, 33 2: 217-226. doi:10.1021/ic00080a008


Author Appleton T.G.
Bailey A.J.
Bedgood Jr. D.R.
Hall J.R.
Title Amino acid complexes of palladium(II). 1. NMR study of the reactions of the diaqua(ethylenediamine)palladium(II) cation with ammonia, betaine, and the amino acids +NH3(CH2)nCO2 - (n = 1-3)
Journal name Inorganic Chemistry   Check publisher's open access policy
ISSN 0020-1669
Publication date 1994-01-01
Sub-type Article (original research)
DOI 10.1021/ic00080a008
Volume 33
Issue 2
Start page 217
End page 226
Total pages 10
Subject 1604 Human Geography
Abstract 15N NMR spectra were obtained for solutions of [Pd(en-15N2)(H2O)2]2+ (1) and the complexes formed from it on addition of alkali, [{Pd(en-15N2)(μ-OH)}n]n+ (n = 2, 3), and [Pd(en-15W2)(OH)2]. In the presence of weak donor anions, NO3 -, SO4 2-, and ClO4 - and dioxane, the 15N NMR peak from 1 was broadened at 298 K, owing to exchange between H2O and these ligands. When betaine (+(CH3)3NCH2CO2-, bet) reacted with 1, the major 15N NMR peaks at 277 K were assigned to [Pd(en)(bet-O)(H2O)]2+ and [Pd(en)(bet-O)2]2+. At higher temperatures, the peaks broadened and coalesced, until by 353 K there was a broad singlet, indicating that intermolecular exchange of betaine between the free ligand and these complexes was rapid. The products of reactions of 1 with ammonia depended on pH. [Pd(en)(NH3)(H2O)]2+, [Pd(en)(NH3)2]2+, [Pd(en)(NH3)(OH)]+, and [{Pd(en)(NH3)}2(μ-OH)]3+ were characterized in solution by 15N NMR. Reaction of 1 (in excess) with glycine (Hgly) gave [Pd(en)(gly-N,O)]+ as the dominant complex over the pH range 4-10. Above pH 10, [Pd(en)(gly-N)(OH)] formed. With excess glycine, at high pH, [Pd(en)(gly-N)2] was the dominant complex. Near pH 2, [Pd(en)(Hgly-O)-(H2O)]2+ was in equilibrium with the N,O-chelate complex, free glycine, and 1. cis-[Pd(NH3)2(H2O)2]2+ with glycine, without addition of acid or base to adjust pH, gave initially [Pd(NH3)2(gly-N,O)]+, but with standing, reaction with the acid liberated gave the isomer of [Pd(NH3)(H2O)(gly-N,O)]+ with ammine trans to glycinate O, as well as [Pd(H2O)2(gly-N,O)]+. Reactions of β-alanine (+NH3(CH2)2CO2 -, Hβala) with 1 were generally similar to those of glycine, except that the N,O-chelate complex was less stable relative to [Pd(en)(Hβala-O)(H2O)]2+ at low pH. Reaction of 1 with γ-aminobutyric acid (+NH3(CH2)3CO2 -, Hγaba) gave a mixture over the pH range 4-8 of the chelate complex [Pd(en)(γaba-N,O)]+ with the isomers of [{Pd(en)(μ-γaba)}2]2+.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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