Olefin complexes synthesis

Coordination-catalyzed ethylene oligomerization into n-a-olefins. The synthesis of homologous, even-numbered, linear a-olefins can also be performed by oligomerization of ethylene with the aid of homogeneous transition metal complex catalysts [26]. Such a soluble complex catalyst is formed by reaction of, say, a zero-valent nickel compound with a tertiary phosphine ligand. A typical Ni catalyst for the ethylene oligomerization is manufactured from cyclo-octadienyl nickel(O) and diphenylphosphinoacetic ester ... 

Synthesis, structure and reactions of chelate metal-olefin complexes... 

Yasuda S, Yorimitsu H, Oshima K (2008) Synthesis of aryliron complexes by palladium-catalyzed transmetalation between [CpFe(CO)2l] and aryl Grignard reagents and their chemistry directed toward organic synthesis. Organometallics 27 4025 027 Jonas K, Schieferstein L (1979) Simple route to Li- or Zn-metalated r -cyclopentadien-yliron-olefin complexes. Angew Chem Int Ed Engl 18 549-550... 

Cationic Fp (olefin) complexes [Fp = f/5-C5H5Fe(CO)2] undergo regio-specific addition of heteroatomic nucleophiles.32 Subsequent ligand transfer (carbonyl insertion) occurs with retention of configuration at the migrating center (R—Fe—CO -> RCOFe).33 A combination of these processes has provided a novel stereospecific azetidinone synthesis which can also be applied to condensed systems.34... 

The use of tri-tert-butylphosphine has produced still higher selectivities, allowing near total control in the synthesis of (A)-vinylsilanes, including alkoxysilanes and disiloxanes.38,39 In the context of a total synthesis of an HMG-CoA reductase inhibitor, hydrosilylation with a chlorosilane catalyzed by a platinum(O) olefin complex, Pt2 [(CH2=CH)Me2Si]20 3 (also known as Karstadt s catalyst), followed by coupling with a 2,6-disubstituted aryl iodide forged a key intermediate shown in Scheme 6.38... 

NQR, 22 216 olefin complexes of, 4 85 in organogermanium compounds, 27 141,143 oxyfluoride, properties of, 11 29 pentacarbonyl dimets of sulfur oxydifluoride imide, 19 203-205 pentafluoride, structure, 27 102 peroxides, 6 325-326 phthalocyanine, 7 54 physical properties of, 11 18 polysulfide complexes, 31 100, 102 envelope conformation, 31 115 synthesis, 31 103-104 [Pt[15]aneS5) f, 35 75, 77 reaction with fluorinated peroxides, 16 120 salts, lattice energy and thermochemistry, 22 52-56... 

This preparation is an illustration of the hydroformylation of olefins (oxo synthesis). The reaction occurs in the presence of soluble catalytic complexes containing metals of Group VIII of the periodic system. Although the metal originally used by Roelen and still largely used in the industry for the production of aliphatic aldehydes and alcohols is cobalt, the most active and selective catalysts are rhodium-containing compounds. The catalytic activity of the other Group VIII metals is in... 

As was mentioned in Section III,A a very useful method of synthesis of olefin complexes involves the displacement of carbon monoxide from metal carbonyls by olefins. Under similar conditions acetylenes usually react to give new ligands, e.g., cyclobutadienes, cyclopentadienones, and quinones (see Sections V,E and VI,C), and it is not surprising, therefore, that the range of known acetylene complexes is smaller than the range of olefin complexes. 

Another example has been found in the author s laboratory. In the course of studies on the synthesis of metal-olefin complexes by means of cathodic reduction in dry organic mediums, a variety of linear oligomers were prepared on the nickel atom formed at the platinum cathode in electrolytic solution (32). The solution contained tetracispyridine nickel perchlorate or nickel dichloride and butadiene in ethanol or dimethoxye-thane, using tetrabutylammonium perchlorate as an electrolyte. 

Such J-mctals as Cu(I) [but not Cu(II)], form a variety of compounds with ethenes, for example [Cu(C2H4)(H20)2]C104 (from Cu, Cu2+, and C2H4) or Cu(C2H4)(bipy)+. It is necessary to mention that, of all the metals involved in biological systems, only copper reacts with ethylene [74b]. Such homoleptic alkene complexes can be useful intermediates for the synthesis of other complexes. The olefin complexes of the metals in high formal oxidation states are electron deficient and therefore inert toward electrophilic reagents. By contrast, the olefin complexes of the metals in low formal oxidation states are attacked by electrophiles such as protons at the electron-rich metal-carbon a-bonds [74c]. 

Saussine, L., H. Mimoun, A. Mitschler, and J. Fisher. 1980. Molybdenum(VI) and vanadium(V) N,N-dialkylhydroxylamino complexes Synthesis, x-ray structure, and reactivity towards olefins. Nouv. J. Chim. 4 235-237. 

Jackstell R, Andreu MG, Frisch A, Selvakumar K, Zapf A, Klein H, Spannenberg A, Rottger D, Briel O, Karch R, Beller M (2002) A highly efficient catalyst for the telomerization of 1,3-dienes with alcohols first synthesis of a monocarbenepalladium(0)-olefin complex. Angew Chem Int Ed 41 986-989... 

Di-jj-chloro-dichlorobis(ethylene)diplatinum(II) is customarily prepared by evaporating an aqueous solution of H[PtCl3(C2H4)] to dryness and then recrystallizing the dimer.1 However, this procedure has not been applied as a general synthesis of other related olefin complexes. The dimer has also been prepared, but with less success, by the reaction of Na2PtCl6 with boiling ethanol.2 The direct reaction of ethylene with platinum(IV) chloride also provides the dimer,3 but yield data are not available and presumably the method is unsatisfactory. 

Reactions of the (Tj5-C5Hs)cobaIt-olefin complexes (26) prepared according to Eqs. (25) and (26) with alkali metals (Li, Na, K) in the presence of olefins lead to the elimination of the second C5H5 ligand from the cobalt (Scheme 5). Complexes 27a and 27b, or the mixed complex 27c are obtained in high yields [Eq. (28)]. The syntheses of the pure complexes 27a and 27b do not, of course, require the isolation of intermediates 26a and 26b. As mentioned previously, synthesis is readily achieved from cobaltocene (24) by reaction with either stoichiometric amounts or excess alkali metal in the presence of COD or ethylene [Eq. (24)]. The alkali metal cyclopentadienides which are formed are easily separated from the cobalt complexes and can be used for the synthesis of cobaltocene (51) [Scheme 5 Eq. (29)]. 

Padin, J. Yang, R. T. New Sorbents for Olefin-Paraffin Separations by Adsorption via 7i-Complexation Synthesis and Effects of Substrates Chem. Eng. Sci., 2000, 55, 2607. 

Treatment of zirconocene dichloride, 50, with 2 equiv. of an appropriate alkyllithium or Grignard reagent generates transient zirconocene olefin complexes that upon loss of alkene provide access to zirconocene, 109, and the powerful reduction chemistry of divalent zirconium.48 Owing to the utility of this reagent in organic synthesis and organometallic reactions, the low-temperature alkylation of zirconocene dichloride, 50, with BunLi has been... 

The synthetic reactions of palladium(O) olefin complexes bearing tertiary phosphine ligands may be classified into four types (eq (52)-(55)) [72-75]. The first type of reaction involves the reduction of Pd(acac)2 with AlEt2(OEt) in the presence of olefins and phosphine ligands and it has been applied to the synthesis of palladium(O) ethylene complexes bearing PPhj, PCy3 and dppe ligands (eq (52)) [72]. 

As described in the previous section. Ni(cod>2 is used as a versatile precursor to organonickel complexes (see Section 12.2). On the other hand, the corresponding palladium complex Pd(cod)2 is too unstable to be handled [77]. Therefore, the more stable palladium(O) olefin complex Pd Cdba) (dba = dibenzylideneacetone) is generally employed instead (eq (56)) [78]. The dba complex can be isolated as air-stable purple crystals and stored at room temperature without decomposition. This complex was applied to the synthesis of various palladium(O) olefin complexes [79] and mono-organopalladium(II) complexes. 

CD of Rhodiumd) Complexes. Figure 2 shows the visible and UV absorption of r 2-olefin complexes of rhodiumd). The synthesis of these complexes has been reported elsewhere. (S) It is seen that r 2-olefins give absorption peaks or shoulders in the regions... 

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