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Organometallic cationic

John, G.R. and Kane-Maguire, A.P, Phosphite addition to organometallic cations to give phosphonium adducts, /. Organomet. Chem., 120, C45, 1976. [Pg.183]

Owing to the high Lewis acidity the group 14 organometallic cations are polymerization catalysts par excellence. so Silanorbonyl cations and triethylsilyl arenium have been shown to be efficient catalysts for metal-free hydrosilylation reactions. Chiral silyl cation complexes with acetonitrile have been applied as cata -lysts in Diels Alder-type cyclization reactions °792 intramolecularly stabilized tetracoordinated silyl cations have been successfully used as efficient catalysts in Mukaiyama-type aldol reactions. [Pg.208]

Our contributions to the chemistry of organometallic cations of group 14 chemistry were supported by the Deutsche Forschungsgemeinschaft (DFG) and the German Israeli Foundation for Scientific Research and Development (GIF). The author wishes to thank the Professors C. A. Reed, A. Sekiguchi, J. Michl and K. Jurkschat for kindly supplying information prior to publication. [Pg.210]

In addition to the cations diseussed above, additional salts of the monoanion 2a have been prepared by substituting various pyridinium salts for the BU4NI utilized in Seheme 2. A signifieant number of salts of 2a have also been prepared via metathesis of [Bu4N][2a] with various metal PFe salts. These methods have thus produced salts of 2a with various organometallic cations ([M(Cp )2], were M = Fe, Mn, Co, Cr). [Pg.72]

In the case of the salts of organometallic cations, the 2a anion adopts only a trans configuration in the crystal structures. However, in all of the pyridinium salts, there is clear evidence for variable amounts of cis-trans disorder, which is somewhat unusual for such thiophenedithiolene complexes. The trans configuration is still predominate for structures of the [BzPy] and [BrBzPy] salts, while the structure of the [FBzPy] salt exhibits 77% cis conformation. In addition to the cis-trans disorder, the 2a anion in the [BrBzPy] salt also exhibits 20% orientation disorder. ... [Pg.74]

This lack of variation of selectivity with reactivity was confirmed in an independent study by Kane-Maguire and Sweigart who found that relative reactivities of amine and phosphine nucleophiles toward a range of organometallic cations were also independent of the nature of the... [Pg.96]

Fig. 10 Plot of E parameters against open circles, benzhydryl cations fdled circles, trityl cations squares, organometallic cations fdled triangles, tropylium ions open triangles, flavylium, xanthylium and other O-, S-, or N-conjugated cations. Fig. 10 Plot of E parameters against open circles, benzhydryl cations fdled circles, trityl cations squares, organometallic cations fdled triangles, tropylium ions open triangles, flavylium, xanthylium and other O-, S-, or N-conjugated cations.
The perhalic acids and their anions are strong oxidising agents, especially Br04-, which is not thermodynamically stable in aqueous solution. They do, however have considerable kinetic stability. Perchlorates of organic or organometallic cations are very dangerous as they may appear stable, but can explode unpredictably with extreme force. [Pg.180]

Scheme 5. The peralkylation or perfunctional-ization reaction this reaction is made possible by the proton-reservoir property of the starting organometallic cation (see Schemes 2 and 3) and is spontaneously reproduced by iteration many times until a steric limit is reached a) hexa-substitution compounds are formed with methyl... Scheme 5. The peralkylation or perfunctional-ization reaction this reaction is made possible by the proton-reservoir property of the starting organometallic cation (see Schemes 2 and 3) and is spontaneously reproduced by iteration many times until a steric limit is reached a) hexa-substitution compounds are formed with methyl...
The net charge on the complex is also an important factor, and organometallic anions are among the most effective electron donors currently available (10). Conversely, the positively charged organometallic cations are useful electron acceptors in measure with the magnitudes of their electron affinities (11). [Pg.53]

Nucleophilic addition to unsaturated ligands, such as olefins, acetylenes, and arenes, coordinated to various metal centers is a useful strategy in organic synthesis (98). The ion-pair interaction of organometallic cations and anions is facile and can successfully lead to the nucleophilic activation of ethylene, acetylene, and benzene (99), for example,... [Pg.96]

Recently, other attempts have been reported by Dai et al. (439) using the complexes 31 (Scheme 26). These authors admit that the efficiency of their materials needs to be improved by optimizing the balance between absorption and nonlinearity. Third-order NLO properties of M(dmit)2 and M(mnt)2 complexes with sandwiched organometallic cations [CpFe(r -C6H6)]+ have also been reported very recently (440). [Pg.462]

Ab initio calculations on hypothetical organometallic cations Cp2Ln+ (Ln = Sc, La) show bent metallocene structures are favoured due to the covalent a bonding contributions involving the totally symmetric metal d orbitals which favor bent structures. Although the contribution of da is lower than dn, its involvement is sufficient to give bent structures [119]. [Pg.442]

Cyclic voltametry of the Rhlu complexes [Rh(R)(salen)py] (R = Me, Pr", Pr1 salen = dianion of bis(salicylidene)ethylenediamine) displays reversible one-electron oxidations of the metal center. The ease of formation of the organometallic cation [Rh(R)(salen)py)+depends on the nature of the... [Pg.1062]

Perchlorate salts of organic or organometallic cations or complexes with organic ligands must be handled with extreme caution substitution of C104 by CF3SO3 or other non-coordinating anions is always advisable. [Pg.72]

When a P(OR)3 molecule serves as a ligand to an organometallic cation, the same sort of reaction can occur,42 for example ... [Pg.412]


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