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Titolo:
Flexible covalent tripods in nonadentate podands: synthesis of tris[3-(6-diethylcarbamoylpyridine-2-carboxamido)propyl]amine and its complexing properties with trivalent lanthanides
Autore:
Renaud, F; Decurnex, C; Piguet, C; Hopfgartner, G;
Indirizzi:
Univ Geneva, Dept Inorgan Analyt & Appl Chem, CH-1211 Geneva 4, Switzerland Univ Geneva Geneva Switzerland 4 ppl Chem, CH-1211 Geneva 4, Switzerland F Hoffmann La Roche & Co Ltd, Div Pharmaceut, PRNS 68 142, CH-4070 Basel, Switzerland F Hoffmann La Roche & Co Ltd Basel Switzerland CH-4070 asel, Switzerland
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
fascicolo: 12, , anno: 2001,
pagine: 1863 - 1871
SICI:
1472-7773(2001):12<1863:FCTINP>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUPRAMOLECULAR COMPLEXES; COORDINATION CHEMISTRY; MASS-SPECTROMETRY; BUILDING-BLOCKS; BINDING UNITS; SOLID-STATE; PHOTOPHYSICAL PROPERTIES; PREDETERMINED PROPERTIES; ELECTRONIC-PROPERTIES; METAL-COMPLEXES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
71
Recensione:
Indirizzi per estratti:
Indirizzo: Piguet, C Univ Geneva, Dept Inorgan Analyt & Appl Chem, 30 Quai E Ansermet, CH-1211 Geneva 4, Switzerland Univ Geneva 30 Quai E Ansermet Geneva Switzerland 4 Switzerland
Citazione:
F. Renaud et al., "Flexible covalent tripods in nonadentate podands: synthesis of tris[3-(6-diethylcarbamoylpyridine-2-carboxamido)propyl]amine and its complexing properties with trivalent lanthanides", J CHEM S DA, (12), 2001, pp. 1863-1871

Abstract

The nonadentate podand tris[3-(6-diethylcarbamoylpyridine-2-carboxamido)propyl]amine (L-14) is prepared according to a multistep strategy using the flexible tris(3-(N-methylamino)propyl)amine (Me-TRPN) covalent tripod. L-14 exists as a statistical mixture of four conformers in solution whose distribution is slightly affected by protonation of the apical nitrogen atom in [L-14 + H](+). The pK(a) value depends on the length of the spacer separating the apical nitrogen and the appended electron-withdrawing tertiary amide groups, and increases by three orders of magnitude when going from the Me-TREN tripod in [L-13 + H](+) (ethylene spacer) to Me-TRPN in [L-14 + H](+) (trimethylene spacer). Reactions of L-14 and [L-14 + H](+) with Ln(ClO4)(3) (Ln = La-Lu) produce flexible and poorly stable 1 : 1 podates [Ln(L-14)](3+) and [Ln(L-14 + H)](4+) in which the terdentate chelating binding units exhibit partial dynamic on-off complexation equilibria. Comparisons of structural and thermodynamic data for [Ln(L-n)](3+) (n = 13 or 14) in solution point to a drastic decrease of the molecular organisation of the podand when the constrained Me-TREN tripod is replaced by the elongated Me-TRPN tripod in nine-co-ordinate lanthanide podates, a crucial limiting factor for the design of supramolecular lanthanide complexes with predetermined properties.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 07:54:58