Isocyanide complexes with alcohols

The reaction of the gold(I) pentafluorophenyl isocyanide complexes with primary and secondary amines as well as alcohols leads to the corresponding gold(I) [62, 65] carbenes (Table 3.2). The addition of amines leads to the corresponding carbenes... 

The reactions of isocyanide complexes with nucleophiles parallel the reactions of metal carbonyls. Alcohols were found to add across the carbon-nitrogen bond of complexed isocyanides (Badley et al., 1969, 1971). Amines... 

Transition metal isocyanide complexes can undergo reactions with nucleophiles to generate carbene complexes. Pt(II) and Pd(II) complexes have been most extensively investigated, and the range of nucleophilic reagents employed in these reactions has included alcohols, amines, and thiols (56) ... 

The nucleophilic addition of alcohols (with alkyl chains) to gold (I) isocyanide complexes [AuCl CNC6H4A(C6H4)xOCnH2n+i ], which will be described below,... 

A very interesting synthetic method was published in 1969 by Richards and co-workers (46). They found that, in the reaction of alcohols with certain isocyanide complexes sueh as those of platinum(II) ], an addition of the alkoxy group to the carbon atom as well as of the hydrogen to the nitrogen atom of the isocyanidc ligand occurs, and one thus obtains the corresponding carbene complexes ... 

Palladium isocyanide complexes react with amines and alcohols to give palladium Carbene Complexes (equation 15) in a reaction that is a nucleophihc attack on the isonitrile carbon. These complexes easily lose a halide if it is trans to the carbene hgand, since the carbene carbon has a high trans influence. The structures of these compounds have the carbene carbon and its two heteroatom groups in one plane, which is perpendicular to the coordination plane of the Pd. 

Unlike the analogous isocyanide Au complexes, which react with alcohols or amines to form carbenes, the Ag complexes rearrange to the formamidate (RN=CHOR ) or formamidine (RNHCH=NR ) species, which are all probably cyclic oligomers such as (4). 

Liquid-crystalline gold isocyanide complexes [C H2n+iO—(CgELj)—O—C(O)—(Cg H4)—NCAuCl] react with alcohols Cmff2m+iOE[ (n = 10 or 11 m = 2 to 5) to form ZJE isomeric mixtures of carbene complexes [isomerism occurs around the C(carbene)—N bond] with mesomorphic properties and provide the first examples of liquid-crystalline metal-carbene complexes421. The isomers can also be separated, with the E form being slightly more stable than the Z form. 

Finally nitrile or isocyanide complexes may be attacked. Thus nitrile complexes with aromatic amines and alcohols give complexes of amidines and imidate esters respectively,298 e.g.,... 

The synthesis of novel bis(isocyanide) species [AufRNQj]" has also been described. Some of these complexes react with alcohols to yield carbene products ... 

The majority of gold(I) carbene complexes are pure organometallic compounds and the are out of the scope of this work. Some halide or triphenylphosphine carbene complexes are known and they will be considered here. Nucleophilic addition of alcohols or amines to gold-coordinated isocyanides is one of the best-established methods to obtain gold carbene derivatives. The reaction of H[Au(CN)2] with propene oxide and estirene oxide yields (cyano)carbene complexes (380) avoiding the intermediate step.2257 A cyclic carbene compound is obtained by reaction of a dinuclear isocyanide with amine (Scheme 32).2258... 

Early work focused on compounds with open-chain carbenes generally synthesized in the coordination sphere of the gold atom, for example, by addition of amines or alcohols to isocyanide ligands in the corresponding gold complexes. Subsequent synthetic approaches have relied on the in situ deprotonation of onium salt precursors by a... 

When coordinated to metal ions in their normal or higher oxidation states, an isocyanide is rendered susceptible to attack at the ligating carbon atom by nucleophilic reagents.1 When alcohols or amines are the nucleophiles, carbene complexes that may be prepared for a variety of metals and substituent groups are obtained. The first fully characterized compounds were of platinum(H),2 and general methods of their preparation, with particular examples, are given below. 

Carbenes are speties with a divalent carbon atom with various substituents and a lone pair of electrons. Classic carbene gold complexes were synthesized in the coordination sphere of the gold atom, addition of amines or alcohols to the coordinated isocyanide ligands. N-Heterocyclic carbenes (Arduengo s carbenes)... 

For alcohol additions, mono- and dicarbene complexes have been synthesized, for palladium, platinum (487-489), and gold (475, 490- 493), from methanol, ethanol, or ethanethiol (494) additions to the isocyanide precursor. The stability of the gold(I) carbenes can be gauged from reactions with halogens which gave the oxidative addition product without loss of the carbene ligand (492). 

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