Reaction of the dilithium salt of the Schiff-base N,N'-o-phenylene-bis(3,5-di-tert-butyl-salicylidene-imine) ((t)Bu(4)salophenH(2)) with 1 equiv. of ZrCl4(THF)(2) in toluene at -78 degrees C affords the dichloro complex ZrCl2[C6H4-1,2-{N=CH-(3,5-(Bu2C6H2)-Bu-t-2-O)}(2)], isolated as a mixture of the C-2v-(3a) and C-2-(3b) symmetry isomers. Thermodynamic and kinetic parameters for the equilibrium between 3a and 3b have been determined and studied by H-1 NMR spectroscopy. Reactions of ZrCl2[C6H4-1,2-{N=CH-(3,5-(Bu2C6H2)-Bu-t-2-O)}(2)] with alkylating reagents gave an intractable, unidentified mixture of products from which the NMR spectra in C6D6 solution are unusable. (c) 2006 Elsevier B.V. All rights reserved.
A zirconium dichloro complex supported by an ancillary stereorigid tetradentate bis(phenoxo-imino) Schiff-base-donor ligand: Evidence for a conformational equilibrium between two solution stereoisomers
CUOMO, Cinzia;GRASSI, Alfonso
2006-01-01
Abstract
Reaction of the dilithium salt of the Schiff-base N,N'-o-phenylene-bis(3,5-di-tert-butyl-salicylidene-imine) ((t)Bu(4)salophenH(2)) with 1 equiv. of ZrCl4(THF)(2) in toluene at -78 degrees C affords the dichloro complex ZrCl2[C6H4-1,2-{N=CH-(3,5-(Bu2C6H2)-Bu-t-2-O)}(2)], isolated as a mixture of the C-2v-(3a) and C-2-(3b) symmetry isomers. Thermodynamic and kinetic parameters for the equilibrium between 3a and 3b have been determined and studied by H-1 NMR spectroscopy. Reactions of ZrCl2[C6H4-1,2-{N=CH-(3,5-(Bu2C6H2)-Bu-t-2-O)}(2)] with alkylating reagents gave an intractable, unidentified mixture of products from which the NMR spectra in C6D6 solution are unusable. (c) 2006 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
