ISSN:
0570-0833
Keywords:
Transition metals
;
Polymers
;
Alkene ligands
;
Electrocatalysis
;
Complexes
;
Alkyne ligands
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An unprecedented series of highly reactive alkene-and diene-complexes of the early transition metals (Groups 3A-5A of the periodic system) have been isolated recently. Diene complexes of this sort (M = Ti, Zr, Hf, Nb, Ta) prefer, besides the (η4-s-cis-diene)metal structure, either a novel bent η4-metallacyclo-3-pentene structure or the unique (η4-s-trans-diene)metal structure. In bis(diene)metal complexes of Nb and Ta the η4-s-cis-dienes assume an unusual exo-endo (supine-prone) geometry. The M—C bonds in these diene-metal complexes generally exhibit highly polarized σ-bonding along with π-bonding character. The complexes therefore undergo a variety of regio- and stereoselective carbometalations with substrates containing C—C, C—O, or C—N multiple bonds. Examples of the products that can be obtained include ketones, vinyl ketones, unsaturated primary, secondary, and tertiary alcohols, as well as diols and unsaturated acids. Mechanistic studies on the stoichiometric and catalytic conversions of unsaturated hydrocarbons provides, inter alia, some insights into the course of polymerization reactions.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/anie.198707231
Permalink
