Isomerization Mechanisms of a Labile Co(II) Octahedral Complex

Autor:	Aurelian Gulea, Andre E. Merbach, Lothar Helm, Fabrice Riblet, Ghenadie Novitchi
Rok vydání:	2006
Předmět:	Denticity Ligand Stereochemistry Kinetics chemistry.chemical_element General Medicine General Chemistry Fluorine-19 NMR Cobalt(ii) Mole fraction Isomer Paramagnetic Chemistry Crystallography Labile chemistry Octahedron 19f nmr QD1-999 Cobalt Isomerization
Zdroj:	CHIMIA, Vol 60, Iss 4 (2006)
ISSN:	2673-2424 0009-4293
DOI:	10.2533/000942906777674769
Popis:	The labile cobalt (II) complex [Co(TUF)2(Pic)2] with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TUF) bidentate and 4-methylpyridine (Pic) monodentate ligands was studied by variable temperature (VT) 19F NMR from 184 to 312 K. In contrast to the solid state, all the isomers are present in a CD2Cl2 solution. Thermodynamic parameters (?H° and ?S°) of each isomer with reference to the trans(N)-trans(CF3)-trans isomer were obtained from the fitting of experimental mole fraction values. A kinetics investigation of the isomerization processes was performed by lineshape analysis of the spectra using the Kubo-Sack formalism. The suggested bidentate bond-rupture mechanism involves the breaking of the weakest Co–O bond (closest to the CF3 withdrawing group) with the TUF ligand.
Databáze:	OpenAIRE
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