Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Allyl complexes dynamic properties

The chiral ir-allyl-Pd(II) intermediates shown in Scheme 84 undergo epimerization. The efficiency of this step and the regiochemistry of the nucleophilic attack to the exo face are very important for obtaining enantioface selection (Scheme 89). Bosnich analyzed the general characteristics of the asymmetric alkylation in terms of the properties of the allylic acetate substrates and of the 7T-allyl-Pd(II) intermediates, which undergo facile o-tc-o rearrangement, readily switching the face of Pd coordination (208). Examination of the dynamic equilibria of a series of cationic ir-allyl-Pd-chiral phosphine complexes has indicated that the 7r-allyl intermediates epimerize 10-100 times faster than the nucleo-... [Pg.107]

Abstract The synthesis and X-ray structure of various octahedral zirconium complexes and their catalytic properties in the polymerization of a-olefins are described. Benzamidinate, amido, allylic, and phosphinoamide moieties comprise the study ligations. For the benzamidinate complexes, a comparison study between homogeneous and heterogeneous complexes is presented. For the phosphinoamide complex, we show that the dynamic symmetry change of the complex from C2 to C2v allows the formation of elastomeric polymers. By controlling the reaction conditions of the polymerization process, highly stereoregular, elastomeric, or atactic polypropylenes can be produced. The formation of the elastomeric polymers was found to be the result of the epimerization of the last inserted monomer to the polymer chain. [Pg.63]

Titanium group allyl compounds are sensitive to air, water, and alcohols. Tetrallyl derivatives of zirconium and hafnium are dynamic compounds. The complex Hf(allyl)4 gives the AX4 type NMR spectrum even at very low temperatures (199 K). The Ti(III) complexes are paramagnetic magnetic moments correspond to one unpaired electron and, for various allyl groups, vary in the 1.47-1.75 BM range. The properties of allyl... [Pg.450]


See other pages where Allyl complexes dynamic properties is mentioned: [Pg.62]    [Pg.432]    [Pg.434]    [Pg.172]    [Pg.478]    [Pg.111]    [Pg.104]    [Pg.341]    [Pg.358]   
See also in sourсe #XX -- [ Pg.434 , Pg.435 , Pg.436 , Pg.437 , Pg.438 ]




SEARCH



Allyl complexes dynamics

Allylation complexes

Allylic complexes, properties

Complex allyl

Complexes, 14 properties

Complexing properties

Dynamic allyls

Dynamic complexes

Dynamic properties

© 2024 chempedia.info