Mono-olefin complexes

Until about 1957, only metals toward the end of the transition series, such as Pd, Pt, Cu, Ag, and Hg, were known to form mono-olefin complexes. In 1959 Schrauzer 219, 220) prepared the first olefin complex of nickel, starting with nickel carbonyl and acrylonitrile ... 

For the reader desiring more information on mono-olefin complexes of the transition metals, a number of excellent reviews are available. Early studies on olefin-metal complexes (primarily of Pt, Pd, Ag, and Hg) have been reviewed by Keller Chatt 27), and Douglas 70). Two more... 

Many 1,3-butadiene complexes, mostly cis, are known. It is necessary to involve two limit forms in the same way as for mono-olefin complexes, the jt complex in which the diene is a L2 ligand (modest n backbonding) and the metallacyclopentene in which the ligand is LX2 (important n backbonding). The latter form corresponds to oxidative coupling (see Chap. 3.3) ... 

Butylenes are C Hg mono-olefin isomers 1-butene, <7j -2-butene, trans-2-huX.en.e and isobutylene (2-methylpropene). These isomers are usually coproduced as a mixture and are commonly referred to as the fraction. These fractions are usually obtained as by-products from petroleum refinery and petrochemical complexes that crack petroleum fractions and natural gas Hquids. Since the fractions almost always contain butanes, it is also known as the B—B stream. The linear isomers are referred to as butenes. 

Mono-olefin and acetylene complexes of nickel, palladium and platinum... 

Herberhold, M. Metall 7r- complexes. Vol. 2. Complexes with mono- olefinic ligands. Amsterdam Elsevier Part I. 1972, Part 11. 1974... 

The initiation reaction in the polymerization of vinyl ethers by BF3R20 (R20 = various dialkyl ethers and tetrahydrofuran) was shown by Eley to involve an alkyl ion from the dialkyl ether, which therefore acts as a (necessary) co-catalyst [35, 67]. This initiation by an alkyl ion from a BF3-ether complex means that the alkyl vinyl ethers are so much more basic than the mono-olefins, that they can abstract alkylium ions from the boron fluoride etherate. This difference in basicity is also illustrated by the observations that triethoxonium fluoroborate, Et30+BF4", will not polymerise isobutene [68] but polymerises w-butyl vinyl ether instantaneously [69]. It was also shown [67] that in an extremely dry system boron fluoride will not catalyse the polymerization of alkyl vinyl ethers in hydrocarbons thus, an earlier suggestion that an alkyl vinyl ether might act as its own co-catalyst [30] was shown to be invalid, at least under these conditions. 

The structure of [(Me2As)(5=CCF F2(AsMe2)Fe3(CO)g] has been reported.Treatment of the mono-olefin chelate [Fe(CO)3(sp)], (sp = o-CH2=CHCgH PPh2) with HX (X = Cl or Br) in hexane gives the Fe complex (34), whose structure has been assigned on the basis of an X-ray study on the Ru—Br analogue. The iron compounds appear to be the first octahedral a-bonded alkyls of Fe". ... 

Owing to their instability at room temperature, complexes of straight-chain mono-olefins with copper(I) halides and with silver nitrate have been characterised mainly by distribution studies in solution, and, in the... 

Mono-olefins (un) react with solid copper(I) halides to form unstable complexes of the type [CuX(un)] (X = Cl, Br), which dissociate into their constituents above 0° (67, 138). Dienes (e.g., butadiene, isoprene, pipery-lene, bicyclo[2,2,l]hepta-2,5-diene, and cyclopolyolefins) form more stable complexes of the type [Cu2X2(diene)J (1,63, 67,138,192), in which a copper atom is attached to each C C bond industrial processes to separate dienes from mono-olefins and paraffins are based on this difference in stability (8). Complexes of the type [Cu(un)]+, [CuCl(un)], and [CuCl2(un)] have been shown to exist in dilute acid solution (15, 67, 138). 

A particularly detailed description was obtained for complexes of Co- A zeolite with mono-olefins (24). Steric effects due to methyl groups adjacent to the double bond resulted in the ligand strength spectrochemical series... 

Herberhold, M. Metal n-Cornplexes. Complexes with Mono-olefinic Ligands. Elsevier Science Amsterdam, 1972. 

M. Herberhold, Metal n-Complexes, Vol. II Complexes with Mono-Olefinic Ligands (Elsevier, Amsterdam, 1972, Chapter 2). 

Al.1.6 Making Metal Complexes of Mono-Olefins and other Unsaturated Organics... 

The rapid 3 4 equilibrium makes the coordinatively unsaturated mono(olefin)zirconocene (-hafnocene) complex 4 an easily accessible organometallic synthon even at extremely low temperatures, a fact that certainly will make its readily available precursor 3 a good starting material for the preparation of many novel organometallic compounds in the future. 

Subsequently, Hiittel and co-workers (303, 306, 307) have described a series of gold(I)-olefin complexes involving both cyclic and acyclic mono- and oligoolefins (Table VI). The 1 1 monoolefin complexes, prepared in almost quantitative yield by reaction of excess olefin with AuCl in ether, are monomolecular and are obtained as colorless crystals. The cyclic olefins, which react as well with aqueous HAUCI4 or NaAuC, form complexes which are more stable than those of the corresponding straight-chain olefins. Formation of the complex results in a low infrared frequency shift in the C=C stretching vibration of 115 cm for the... 

In 1938 Kharasch and co-workers described a method generally applicable for preparing mono-olefin palladium complexes (14 ). Palladium (II) chloride reacted with warm benzonitrile to form the complex bis(benzonitrile)-palladium chloride, and the latter reacted directly with olefins such as ethylene, styrene, cyclohexene, etc., as follows ... 

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