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Titolo:
Cyanide exchange on Tl(CN)(4)(-) in aqueous solution studied by Tl-205 andC-13 NMR spectroscopy
Autore:
Banyai, I; Glaser, J; Toth, I;
Indirizzi:
Univ Debrecen DE, Dept Phys Chem, H-4010 Debrecen, Hungary Univ Debrecen DE Debrecen Hungary H-4010 Chem, H-4010 Debrecen, Hungary Royal Inst Technol, KTH, Dept Chem, S-10044 Stockholm, Sweden Royal Inst Technol Stockholm Sweden S-10044 m, S-10044 Stockholm, Sweden Univ Debrecen DE, Dept Inorgan & Analyt Chem, H-4010 Debrecen, Hungary Univ Debrecen DE Debrecen Hungary H-4010 Chem, H-4010 Debrecen, Hungary
Titolo Testata:
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
fascicolo: 7, , anno: 2001,
pagine: 1709 - 1717
SICI:
1434-1948(200107):7<1709:CEOTIA>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR MAGNETIC-RESONANCE; EQUILIBRIUM DYNAMICS; CHEMICAL EXCHANGE; HYDROGEN-CYANIDE; SPY NUCLEI; COMPLEXES; SYSTEM; RELAXATION; KINETICS; BROMIDE;
Keywords:
ligand exchange; thallium; cyanides; TlNMR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Banyai, I Univ Debrecen DE, Dept Phys Chem, H-4010 Debrecen, Hungary Univ Debrecen DE Debrecen Hungary H-4010 010 Debrecen, Hungary
Citazione:
I. Banyai et al., "Cyanide exchange on Tl(CN)(4)(-) in aqueous solution studied by Tl-205 andC-13 NMR spectroscopy", EUR J INORG, (7), 2001, pp. 1709-1717

Abstract

Dynamics of cyanide exchange between Tl((CN)-C-13)(4)(-) and (CN-)-C-13 was studied by means Tl-205 and C-13 NMR. The rate law consists of two parts:w = k(CN)[Tl(CN)(4)(-)][CN-] + k(OH)[Tl(CN)(4)(-)][CN-][OH-] with k(CN) = 9.7(+/-0.4) x 10(6) M(-1)s(-1) and k(OH) = 5.4(+/-0.4) x 10(10) M(-2)s(-1). It was shown that the exchange between the two cyano species can be studied, not only by C-13 NMR, but also by Tl-205 NMR using the heteronuclear carbon-thallium scalar coupling as an indicator, despite the fact that only one Tl site is present in the system. The reaction mechanism is discussed in terms of an associative interchange mechanism, I-A. Penetration of the incoming cyanide ion into the coordination sphere of Tl(CN)(4)(-) Tl(CN)(4)(OH)(-) is suggested to be the rate-determining step for the two parallel reactions paths. Possible reasons for the strong labilizing effect of the cyanide ligand is discussed in the light of thermodynamic and structural data. The possibility of detection of an exceptional exchange reaction, namely cyanide exchange between two Tl(CN)(4)(-) entities by a direct encounter was theoretically settled, but found to be too slow to be detected.

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Documento generato il 03/04/20 alle ore 04:26:25