Isocyanides oxidation

Group IV Donors. A new class of Pt complex of the formula [Pt(PPh3)2-(CNBu )] has been isolated from the reaction between [Pt(PPh3)2(C2H4)] and free isocyanide. Further treatment with CO gave [Pt(PPh3)2(CNBu )(CO)], and comparison of the v(NC) frequencies in these two new complexes suggests that CO is a more effective ji-acceptor than the isoelectronic isocyanide. Oxidative addition reactions were also reported. ... 

BENZYL ISOCYANIDE OXIDATION OF 5-AMINOTETRAZOLES (Benzene, isocyanomethyl)... 

The reaction of methyl or cyclohexyl isocyanide with Ni02(CNBu-r)2 produces a mixture of tert-butyl and either methyl or cyclohexyl isocyanate, and it is considered important that the formed isocyanate complex be kinetically labile for achieving successful isocyanide oxidation. 

Many papers devoted to electrochemical processes of oxidation and reduction of metal isocyanide complexes have also appeared. It has been found that the ease of oxidation increases when the number of carbonyl ligands in the coordination sphere decreases and as a result of substitution of aryl isocyanides by alkyl isocyanides. Oxidation of [Cr(CNR)6] to [Cr(CNR)6] proceeds more easily in the case of alkyl isocyanides while reduction of Cr(II) complexes to Cr(I) compounds and Cr(I) complexes to Cr(0) compounds takes place more readily for aryl isocyanide ligands. " " " >... 

The oxidation of alkylisocyanides to alkylisocyanates is catalyzed by a variety of metal complexes [82,118,147]. Included among the complexes which have been reported to catalyze this reaction are [Ni(r-BuNC)4], [Ni(r-BuNC)2(02)], and [RhCl(Ph3P)3j. When ether solutions of [Ni(r-BuNC)4] were contacted with oxygen at — 20°C the dioxygen complex (Ni(r-BuNC)2(02)] crystallized from solution. Other catalysts for isocyanide oxidation are Ws(cycloocta-l, 5-diene) nickel [Ni(l, 5-C8Hi2)2], and Ws(cycloocta-l,5-diene)cobalt. 

Lithium 1,2,4-triazolate with [Rh2( j,-Ph2PCH2PPh2)(CO)2( j.-Cl)]PFj. gives the A-framed complex 177 (L=L = CO) (86IC4597). With one equivalent of terf-butyl isocyanide, substitution of one carbon monoxide ligand takes place to yield 177 (L = CO, L = r-BuNC), whereas two equivalents of rerr-butyl isocyanide lead to the product of complete substitution, 177 (L = L = r-BuNC). The starting complex (L = L = CO) oxidatively adds molecular iodine to give the rhodium(II)-rhodium(II) cationic species 178. 

A few isocyanides of palladium and platinum are known in the zerovalent oxidation state. The best characterized compounds involve triangular M3 clusters with M-M bonds. 

Conversion of epoxides into /3-hydroxy isocyanides—preparation of trans-2-isocyanocyclohexanol, using TMSCN to open cyclohexene oxide with trans stereochemistry, followed by KF/MeOH cleavage of the intermediate silyl ether. 

Malonic acid, amino-, diethyl ester, HYDROCHLORIDE, 40, 24 Malonic acid, bts(hydroxymethyl)-, DIETHYL ETHER, 40, 27 Malonitrile, condensation with tetra-cyanoethylene, 41, 99 2-Mercaptopyrimidine, 43, 6S hydrochloride of, 43, 68 Mercuric oxide in preparation of bromo-cyclopropane, 43, 9 Mesityl isocyanide, 41,103 5-Methallyl-l,2,3,4,5-pentachlorocyclo-pentadiene, 43, 92 Methane, dimesityl-, 43, 57 Methanesiileinyl chloride, 40, 62 Methanesulfonic acid, solvent for making peroxybenzoic acid from benzoic acid, 43, 93... 

Isocyanides [RNC] (174, 175) are isoelectronic with CO and have been extensively used as CO analogs in studies of heme proteins (176-180). W-Butyl isocyanide (N-BIC) behaves as a CO analog at both the CODH and ACS active sites (181). N-BIC competes with CO in the CO oxidation reaction, is a sluggish reductant, and causes EPR spectral changes at Clusters A, B, and C similar to those elicited by CO. 

Coordination to an isocyanide can either raise or lower the value of cn depending on the relative contributions of a- and rr-bonding. These contributions are dependent on metal orbital energies, which are influenced by oxidation state and by other ligands present. 

Still, the ease of oxidation is obviously a property of considerable chemical importance. These differences require that the choice of aryl vs. alkyl isocyanides not be taken lightly. 

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)]. 

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