Olefin transition metal complexes structure

Although the first olefin-transition metal complex, potassium ethylene trichloroplatinite, K[C2H PtCl3], was discovered in 1827, it was not until 1953 that its correct structure was elaborated. Extension by Chatt and... 

Structural information on the 10 bonding in some organo-transi- (25) tion metal complexes The structural chemistry of organo- 43 transition metal complexes some (159) recent developments Structure of 7r-olefinic and 77- 33 acetylenic complexes of transi- (114) tion metals... 

An appreciable number of monographs and reviews deal with the meth-Q rsi,275,329-333 jjjg j j.gg gj jpunt of experimental work that has been performed provides a possibility for establishing favorable conditions of epoxidation with regard to the roles of the catalyst, the organic hydroperoxide, the structure of the olefin, and the medium. Simitar to the hydrogen peroxide-transition-metal complex reaction, this is an electrophilic reaction (Eq. 30). ... 

As is well known, the nucleophilic addition to the C-C double bond can be promoted very effectively by r-coordination of the olefin in a cationic low-spin transition metal complex. Many examples are described in the literature where amines react smoothly with transition metal-ethylene complexes forming )ff-ammonioethyl complexes [1-3]. Very often these complexes are isolable in the pure state, and in the case of the platinum(II) complex [PtCl2(Et2NH) (CH2CH2NHEt2)j the stmcture has also been proved by X-ray crystal structure analysis [4]. 

The chemistry of //// //-metallocene compounds has been the subject of several reviews. Structural aspects affecting the catalytic activity and the application of these complexes as catalysts for the homo- and co-polymerization of olefins have been considered.323 The evolution of the //// //-bridge complexes in terms of the various synthetic approaches used to construct the bridged ligand framework, the variety of bridges introduced, and the effect of the bridge on the structure and reactivity of ////.y//-titanocene and other transition metal complexes as compared with their unbridged counterparts has been reviewed.1634... 

Coordination polymerization of dienes has progressed significantly within the last decade. Selective polymerization of 1,3-dienes is reinforced by conventional transition metal catalysts and by new organolanthanide catalysts. Nonconjugated dienes also polymerize selectively to produce polymers with cyclic units or vinyl pendant groups. Living polymerization of dienes has become common, which enabled preparation of block copolymers of dienes with alkenes and other monomers. Another new topic in this field is the polymerization of allenes and methylenecycloalkanes catalyzed by late transition metal complexes. These reactive dienes and derivatives provide polymers with novel structure as well as functionalized polymers. The precision polymerization of 1,2-, 1,3-, and l,n-dienes, achieved in recent years, will be developed to construct new polymer materials with olefin functionality. 

In contrast to Group IV-based polymerization catalysts, late transition metal complexes can carry out a number of useful transformations above and beyond the polyinsertion reaction. These include isomerization reactions and the incorporation of polar monomers, which have allowed the synthesis of branched polymer chains from ethylene alone, and of functional polyolefins via direct copolymerization. The rational design of metallocene catalysts allowed, for the first time, a precise correlation between the structure of the single site catalyst and the mi-crostructure of the olefin homo- or copolymer chain. A similar relationship does not yet exist for late transition metal complexes. This goal, however, and the enormous opportunities that may result from new monomer combinations, provide the direction and the vision for future developments. 

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