Platinum complexes isocyanides

Since the initial report on the addition reactions of palladium(II) and platinum(II) isocyanide complexes by Badley et al. (S), a rather substantial number of further examples have been reported. These are summarized in Table II. 

Platinum(II) isocyanide complexes of the general formulas [PtL4], [PtL3X], and PtL2X2 and substituted derivatives thereof (L = RNC, X = halogen, H, R, etc.), have been studied recently and will be the main subjects of discussion. It may be observed that much work on complexes of the first and third molecular stoichiometries had been reported previously. 

Aldol reactions of isocyanides with aldehydes are catalyzed by cationic platinum complexes having P-C-P or N-C-N ligands in the presence of a catalytic amount of an amine base to give 2-oxazolines (Equation (126)) 48S>485a>485b Platinum-coordinated a-isocyano carbanions presumably serve as nucleophiles toward aldehydes. Low to moderate enantioselectivities were obtained by using chiral platinum complexes.485 4853... 

Platinum(I) isocyanide complexes are formed when Na2PtCl4 reacts with methyl isocyanide, and the product isolated by addition of AgPF6 (equation 116). The structure has two square planar platinums linked by a Pt—Pt bond, with the two Pt(CNMe)3 units perpendicular. The NMR spectrum shows that intramolecular rearrangements occur involving the tetrahedral deformation of one Pt center followed by rotation about the Pt—Pt bond.353 354... 

Platinum(IV) isocyanide complexes PtCU(CNR)2 and [PtCl2(CNR)2(PMe2Ph)2]2+ have been prepared by the addition of Cl2 to the corresponding platinum(II) compounds (equation 118).363 It is probable that the trans influence of the isocyanide ligand on platinum(IV) is greater than that of a tertiary phosphine. 

The most common reaction of platinum(II) isocyanides is their reaction with nucleophiles. This reaction is a useful one for the formation of platinum carbene complexes, and this will be discussed in the next section. 

Chemical routes to palladium(I) and platinum(I) isocyanide complexes have been devised. Addition of CNMe to an aqueous solution of [MC14]2-(M = Pd, Pt) resulted in the rapid formation of [M(CNMe)4]2+ cations, which were isolated as the hexafluorophosphate salts. On standing, however, the cations [M(CNMe)4]2+ slowly converted over 18 hr to [M CNMe ]2 ... 

Typical platinum complexes that have recently been prepared from alcoholic KOH solutions and platinum isocyanide precursors are trans-Pt C(OMe)NR)(CHNR)(PEt3)2 (R = C6H4Me-p) (440, 451) and... 

Platinum complexes (continued) with aryls, thallium adducts, 3, 399 with bis(alkynyl), NLO properties, 12, 125 with bisalkynyl copper complexes, 2, 182-186 with bis(3,5-dichloro-2,4,6-trifluorophenyl), 8, 483 and C-F bond activation, 1, 743 in C-H bond alkenylations, 10, 225 in C-H bond electrophilic activation studies, 1, 707 with chromium, 5, 312 with copper, 2, 168 cyclometallated, for OLEDs, 12, 145 in diyne carbometallations, 10, 351-352 in ene-yne metathesis, 11, 273 in enyne skeletal reorganization, 11, 289 heteronuclear Pt isocyanides, 8, 431 inside metallodendrimers, 12, 400 kinetic studies, 1, 531 on metallodendrimer surfaces, 12, 391 mononuclear Pt(II) isocyanides, 8, 428 mononuclear Pt(0) isocyanides, 8, 424 overview, 8, 405-444 d -cP oxidative addition, PHIP, 1, 436 polynuclear Pt isocyanides, 8, 431 polynuclear Pt(0) isocyanides, 8, 425 Pt(I) isocyanides, 8, 425 Pt(IV) isocyanides, 8, 430... 

A. Burke, A. L. Balch, and J. H.Enemark, Palladium and Platinum Complexes Resulting from the Addition of Hydrazine to Coordinated Isocyanide, J. Am. Chem. Soc. 92,2555-2557 (1970). 

Isocyanide insertion reactions have been studied extensively for nickel, palladium, and platinum complexes. As early as 1968, cyclohexylisocyanide was reported to insert into the nickel-carbon bond of Ni(fj -C5Hs)R(PPh3), giving the following cyclo-hexylimino derivatives ... 

Hi. Metal—Metal Bond. Puddephatt and co-workers have reported the synthesized polymers with main-chain Pt-Pt bonds via the reaction of a platinum complex with various diacetylides and diisocyanides (Scheme 2.4).74 The reaction of 26 with diacetylides formed oligomers possessing low solubility. Polymers isolated from the reactions of 26 with diisocyanides did not possess any uncoordinated isocyanide groups. 

The additions of bimetallic reagents such as the silicon-metal and tin-metal compounds to the carbon-carbon multiple bonds have been extensively studied however, there are few reports concerning the metal-boron compounds as shown above. Miyaura and co-workers have examined the addition reaction of tetraafkoxydiboron to alkynes and found that only the platinum complexes such as Pt(PPh3)4 exhibited excellent catalytic activity (Scheme 24). Pd(PPh3)4 and Pd(OAc)2-isocyanide complexes, which have been the best catalysts for the silyl- and stannyhnetallation, were ineffective because their oxidative addition to palladium(0)-phosphine complexes is very slow. ... 

Platinum Complexes with Carbonyl, Isocyanide, and Carbene Ligands ... 

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