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Titolo:
Amide group coordination to the Hg2+ ion. Potentiometric, H-1 NMR and structural study on Hg2+-N-protected amino acid systems
Autore:
Saladini, M; Menabue, L; Ferrari, E; Iacopino, D;
Indirizzi:
Univ Modena & Reggio Emilia, Dept Chem, I-41100 Modena, Italy Univ Modena & Reggio Emilia Modena Italy I-41100 , I-41100 Modena, Italy
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
fascicolo: 9, , anno: 2001,
pagine: 1513 - 1519
SICI:
1472-7773(2001):9<1513:AGCTTH>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR MAGNETIC-RESONANCE; X-RAY-DIFFRACTION; PHENYLSULFONYL DERIVATIVES; COPPER(II) COMPLEXES; MOLECULAR-STRUCTURES; TERNARY COMPLEXES; AQUEOUS-SOLUTION; BINDING ABILITY; SOLID-STATE; 2,2'-BIPYRIDINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
49
Recensione:
Indirizzi per estratti:
Indirizzo: Saladini, M Univ Modena & Reggio Emilia, Dept Chem, Via Campi 183, I-41100Modena, Italy Univ Modena & Reggio Emilia Via Campi 183 Modena Italy I-41100
Citazione:
M. Saladini et al., "Amide group coordination to the Hg2+ ion. Potentiometric, H-1 NMR and structural study on Hg2+-N-protected amino acid systems", J CHEM S DA, (9), 2001, pp. 1513-1519

Abstract

The binary complexes of Hg2+ formed by N-carbonyl and N-sulfonyl amino acids, which are ligands containing peptide and sulfonamide groups respectively, are investigated in aqueous solution by H-1 NMR, UV spectroscopy and potentiometry. The corresponding ternary systems with 2,2'-bipyridine are studied in aqueous solution by potentiometry and in DMSO solutions by H-1-NMR. All the amino acids behave as simple carboxylate ligands at acid pH, while,around neutrality, N-p-tolylsulfonylglycine (tsglyH(2)), N-p-tolylsulfonyl-beta -alanine (ts-beta -alaH(2)) and N-2-nitrophenylsulfonylglycine (NO(2)psglyH(2)) switch to dianionic N,O-bidentate chelating ligands due to the involvement of the deprotonated amide nitrogen as an additional donor site. The Hg2+ ion is ineffective in promoting peptide nitrogen deprotonation in N-benzoylglycine (bzglyH). The binary and ternary species formed in aqueoussolution and their stability constants are determined and compared with those of the homologous complexes of Pd2+, Cu2+, Cd2+ and Pb2+. The molecularstructure of [Hg(bpy)(2)(NO2-psgly-N,O)].0.5H(2)O is determined by X-ray crystallography. It represents a rare example of Hg2+ N,O coordination by anamino acid molecule. In the complex Hg2+ shows a distorted octahedral environment with a N5O donor set. Four nitrogen atoms are derived from the two bpy ligands, while the oxygen and the fifth nitrogen are from the NO2-psglydianion. New information on the solution and solid state chemistry of Hg2with ligands of biological interest is provided which may be of great relevance in understanding the mechanism of metal toxicity.

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Documento generato il 30/10/20 alle ore 09:49:07