Butadiene complexes with silver

Bis(butadiene) complexes, with tantalum, 5, 173 Bis(z-butanethiolato) complexes, with bis-Cp Ti(IV), 4, 601 Bis(calixarene) complexes, as organic molecule hosts, 12, 799 Bis(carbene) complexes with gold(I), 2, 287-288 with manganese, 5, 780, 5, 826 with mercury, 2, 429 with palladium, 8, 230 with silver , 2, 206... 

Metal-catalyzed [4 + 2 + 2] cyclotrimerizations of either heteroatom-containing enyne 62 with 1,3-butadiene (Eq. 17) [42] or heteroatom-containing dienyne 64 with an alkyne (Eq. 18) [43] are effected by cationic rhodium complexes generated in situ from a chlo-rorhodium complex modified with silver salts. These processes afford eight-membered ring products 63 and 65, respectively. In both processes, the nature and amount of the silver salt profoundly affect the outcomes. 

The development of methods to effect nucleophilic addition to carbon-carbon double bonds by prior activation with metal cations has been applied, at least in a preliminary way, as a method of pyrrole ring closure. The conversion of butadienes to N-substituted pyrroles can be accomplished in two stages. In acetic add, 1,4-dienes react with PdnCl2 to give tr-allyl complexes with introduction of acetate at C-4. The ir-allyl complexes then react with amines to give a l-amino-4-acetoxy-2-butene (equation 70). When the addition of the amine is carried out in the presence of a silver salt and triphenylphosphine, a pyrrole is isolated, probably by cyclization of the amino-substituted allyl-Pd complex (equation 71) (81CC59). Although this procedure is attractive in terms of the simplicity of the... 

The norbornadiene complexes of AgNOs (577) and AgBF4 (491) are quite analogous in stoichiometry to those of 1,3-butadiene with the same salts. A structural analysis (28) of the 1 2 complex (C7Hg)(AgNOg)2 has shown chains of silver nitrate molecules cross-linked by norbornadiene molecules (Fig. 11). In this complex, each silver ion is coordinated... 

The stability constants of silver ion complexes have been evaluated by classical partition techniques (130,131) and more recently by the measurement of dissociation pressures (132,133) and the methods of gas-solid (134) and gas-liquid chromatography (135,136). The use of supported solutions of silver nitrate as a stationary phase for the separation of olefins is now quite general. Enthalpies of formation have been recorded for olefin complexes of silver borofluoride (132), for silver nitrate complexes with cyclic olefins (131) and for silver nitrate-butadiene complexes (133) the results are summarized, together with some values for the ethylene-silver ion complex, in Table XXXVIII. 

It is interesting to compare the -AH values for the formation of [Ag(l-butene).N03] (-42.4 kJ mol-1) obtained by Francis S2> with that obtained by Quinn et al. for the corresponding bis-complex, [Ag( l-butene)2.BF4] (-50.2 k.T mol-1), i.e. somewhat lower than half. The decomposition pressure of the solid formed from the interaction of butadiene with silver nitrate indicated the presence of two complexes S3> [Ag(C4H6)N03] I and [Ag(C4H6)0 sN03] II. Their enthalpies of formation were found to be -45.2 kJ mol-1 respectively and the proposed structures are as shown below. The more likely structure for II is the polymeric structure (a)... 

Copper (I) complexes of olefins have been less widely studied but have been found to be analogous to silver(I) complexes in several ways. It was shown 54>, that solid cuprous chloride absorbed ethylene, propylene and isobutylene and solid cuprous bromide absorbed ethylene to give 1 1 complexes, while diole-fms (butadiene and isoprene) and acetylenes were reported S6> to form complexes with a 2 I copper olefin (or acetylene) stoichiometry. Andrews and... 

The oligomerization and cooligomerization of conjugated dienes are representative reactions that proceed via transition-metal Jt-allyl intermediates. When (CsMesjRuCljt/ -butadiene) in dichloromethane was treated with an acetone solution of an equimolar amount of silver trifluoromethanesulfonate (AgOTf) in the presence of excess butadiene at ambient temperature, after which the mixture was allowed to react with carbon monoxide (1 atm), a cationic 1,5-cyclooctadiene carbonyl complex, [(C5Me5)Ru(CO)( -l,5-C8Hi2)]OTf, was isolated in 95% yield (Eq. 

Olefin epoxidation is not only important in the manufacture of bulk chemicals, e. g. ethylene and propylene oxides, but is also a widely used transformation in the fine-chemicals industry [1], Ethylene oxide is manufactured by vapor-phase oxidation of ethylene, with air or oxygen, over a supported silver catalyst [2], This method is not generally applicable as olefins containing allylic or other reactive C-H bonds give complex mixtures of products with low epoxide selectivity. The method has recently been extended to some other olefins that do not contain reactive allylic C-H bonds, e. g. butadiene, styrene, norbornene, and tert-butyl ethylene [3]. Some of these products, e. g. butadiene monoepoxide and styrene oxide, have potential applications as fine chemicals/intermediates. 

For olefin Ti-complexes, copper(II) halides as fine powders react with butadiene, norbornadiene, cyclooctadiene or dicyclopentadiene to give the corresponding olefin complex (2-4). Some olefins readily form silver nitrate complexes (2-5) in an aqueous or alcoholic solution. 

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