Alkyl and aryl complexes

Formed by Reaction of Complex Halides with Grignard and Lithium Reagents 

An interesting point which arose in connection with the cobalt and 

This suggested that if all the halogen atoms in the complex compounds of the transition metals could be replaced by hydrocarbon radicals, the resultant complex, for example, K2PtR4, should be stable. The main problem is to find a method of synthesis whereby one does not go through an unstable [PtR2Cl2] type of intermediate on the way, and we have not been able to achieve this. 

Now there are many examples of the formation of metal-carbon bonds by the splitting of carbon-hydrogen bonds in complexes of transition metals in low oxidation states with aromatic or unsaturated hydrocarbon moieties, but only one other example has been discovered of the splitting of a saturated aliphatic carbon-hydrogen bond. The fact that an aliphatic carbon-hydrogen bond can be split at all holds out hope that at some time a system may be discovered capable of reacting under mild conditions with saturated hydrocarbons, with all its implications for the petrochemical industry. 

Hofmann and von Narbutt (5J) in 1908 described some compounds formed by the reaction of aqueous potassium chloroplatinate(II) in aqueous alcohols (ROH) with dicyclopentadiene. They formulated them as (XI) in which ROPtCl had added across one of the double bonds of the diene. This formulation could not be correct because it 

Very few a alkyl or aryl complexes, apart from those also containing carbonyl (Section II) or cyclopentadienyl (Section VII) ligands, have been studied by electrochemical methods. Such methods should prove invaluable in the characterization of early transition metal aryls for which extensive redox series apparently exist. 

Sodium naphthalide and [W (CH2)2-o-C6H4 3] (E° = - 1.68 V) in thf yield the corresponding monoanion (228), and 1,2-diketonate complexes such 

Sodium or magnesium amalgam reduction of [RuCl2(PPh3)4] in MeCN affords the ortho-metallated complex [RuH(C6H4PPh2XNCMeXPPh3)2] 

Transition-metal-alkyl bonds can be formed by a variety of reactions that include metathetical replacement of a halide ion, oxidative addition, and insertion of an alkene into a metal-hydride bond. A similar set of reactions is available for the synthesis of transition-metal-aryl bonds, although the analogous insertion of a benzyne intermediate into a metal-hydride bond is not particularly viable as a synthetic route. For alkyl complexes that have longer chains than methyl, thermal decomposition to give the metal-hydride complex by a j5-hydrogen transfer reaction is frequently observed at ambient temperature. 

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Alkene complexes Ammine complexes Aqueous chemistry Arsine complexes Binary compounds Bipyridyl complexes Bond lengths acetylacetonate alkene complexes alkyl and aryl complexes ammine complexes aqua ion... 

B. Ruthenium and Osmium o-Bonded Alkyl and Aryl Complexes. 266... 

The first ruthenium porphyrin alkyls to be reported were prepared from the zerovalent dianion, [Ru(Por)] with iodomethane or iodocthane, giving the ruthe-nium(lV) dialkyl complexes Ru(Por)Me2 or Ru(Por)Et2 (Por = OEP, TTP). Alternatively, the Ru(lV) precursors Ru(Por)X2 react with MeLi or ArLi to produce Ru(Por)Mc2 or Ru(Por)Ar2 (Ar = / -C(,H4X where X = H, Me, OMe, F or Cl) 147-149 The osmium analogues can be prepared by both methods, and Os(Por)R2 where R = Me, Ph and CH2SiMe2 have been reported.Some representative structures are shown in Fig. 5, and the preparation and interconversion of ruthenium porphyrin alkyl and aryl complexes are shown in Scheme 10. 

Substantially more work has been done on reactions of square-planar nickel, palladium, and platinum alkyl and aryl complexes with isocyanides. A communication by Otsuka et al. (108) described the initial work in this area. These workers carried out oxidative addition reactions with Ni(CNBu )4 and with [Pd(CNBu )2] (. In a reaction of the latter compound with methyl iodide the complex, Pd(CNBu )2(CH3)I, stable as a solid but unstable in solution, was obtained. This complex when dissolved in toluene proceeds through an intermediate believed to be dimeric, which then reacts with an additional ligand L (CNBu or PPh3) to give PdL(CNBu )- C(CH3)=NBu I [Eq. (7)]. 

Insertion reactions of platinum(II) alkyl and aryl complexes (144, 153, 171), nucleophilic displacement of isocyanide from [Pt(PRj)2(CNCH3)2] (147) and additions of alcohols and related substances to isocyanides bonded to platinum (8, 9, 25, 33, 34, 100, 117) were discussed earlier. 

Preparation/Formation of Cp2Ti(CO)2 via Titanocene Alkyl and Aryl Complexes... 

The cis/trans isomerization of platinum(II) complexes is a subject which will be discussed in some detail when the halide (Group VII) complexes are covered. Nevertheless the importance of reductive elimination reactions of platinum(II) alkyl and aryl complexes makes it imperative that this reaction be discussed here for alkyl and aryl platinum(II) compounds. 

Alkyl and aryl complexes of the type [AuRL] may also be prepared by reaction of a halide complex with a Grignard reagent. Thus have been... 

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