A. Vitagliano

Electrophilicity of coordinated carbon monoxide in alkoxydienylplatinum(II) carbonyl complexes : Synthesis of (diene)platinum(II) alkoxycarbonyl complexes

Abstract If alkoxydienyl complexes of the type [Pt(dieneOR)Cl] 2 are allowed to react with carbon monoxide under mild conditions, unstable carbonyl complexes are formed. The carbonyl complexes may react with an alcohol to give alkoxycarbonyl complexes of the type (diene)PtClCOOR. This reaction involves nucleophilic attack of alcohol on the coordinated carbonyl group, and expulsion of the alkoxyl group from the dienyl moiety with formation of a coordinated carbonue5f8carbon double bond. This reaction, however, is not of general occurrence. A comparison is made between the electrophilicities of coordinated carbon monoxide and coordinated carbonue5f8carbon double bond.

Molecular structure of η5-[Pd(CH2CHCMeCH2CH2CHCMe2)-(MeCN)](BF4), A cationic π-allylpalladium complex with an almost in-plane intramolecular olefin coordination

The complex η5-[Pd(CH2ue5f4CHue5f4CMeCH2CH2CHue5fbCMe2)-(MeCN)](BF4), a model for a key intermediate in diene polymerization, crystallizes in the monoclinic space group P21/c, a 11.362(2), b 13.655(4), c 10.046(2) A, β 134.80(1)°. The structure was solved by conventional Patterson and Fourier syntheses and refined by full matrix least squares techniques to a final discrepancy index R = 0.058 for 1710 independent reflections. The palladium and nitrogen atoms, the center of gravity of the allyl triangle, and the middle point of the coordinated double bond are coplanar. The side chain of the organic moiety is located in the syn position with respect to the η3-allyl group. The orientation of the coordinated double bond, which forms an angle of 26° with the coordination plane, is novel for palladium(II) complexes.

Four membered chelate aminoalkyl and aminoalkenyl complexes of platinum(II). The molecular and crystal structure of [PtCH2CH2NMe2Cl(PPh3)] and [PtC(=CMe2)CH2NMe2Cl(PPh3)]

Abstract Single-crystal x-ray diffraction structure determinations have been performed on two platinum(II) complexes containing a cyclometallated four-membered ring: [ PtCH 2 CH 2 N Me2Cl(PPh3)] (I) and [ PtC(=CMe 2 )CH 2 N Me2Cl(PPh3)] (II). The crystal data are as follows: for complex I, space group monoclinic, P21/n, a = 9.488(8) A, b = 19.320(6) A, c = 11.913(4) A, β = 97.63(7)°, Z = 4; for complex II, space group monoclinic, P21/a, a = 19.231(6) A, b = 12.023(5) A, c = 10.256(4) A, β = 95.60(6)°, Z = 4. The structures were solved by conventional Patterson, Fourier, and full matrix least-squares refinement techniques. The final consistency indices R and Rw are 0.049 and 0.062 (complex I, 2946 independent reflections), and 0.036 and 0.055 (complex II, 3437 independent reflections). Both compounds show the usual square-planar arrangement of the ligands, somewhat distorted by the presence of the four-membered ring which markedly deviates from planarity. The Ptue5f8C bond length, the Cue5f8Ptue5f8N bond angle and the puckering of the ring are 2.055(11) A, 70.6(4)°, and 8.3° for complex I, and 2.002(7) A, 68.6(3)°, and 25.2° for complex II respectively.

Isolation, characterization and resolution of 1,3,5,7-tetramethyl-2,6,9-trioxo-bicyclo[3.3.1]nona-3,7-diene

Abstract 1,3,5,7-Tetramethyl-2,6,9-trioxo-bicyclo[3.3.1]nona-3,7-diene, a dimer of acetylacetone which is formed as a coordinated species through a Pt(II) promoted condensation, can be displaced from the complex by sodium cyanide treatment. This new compound forms stable chelate π-complexes with Pd(II) and Rh(I) and has been resolved into optical isomers by fractional crystallization of a diastereoisomeric Rh(I) complex.

Four-membered chelate aminoalkenyl complexes of platinum(II). Synthesis, carbonylation and oxidation to aminoacidato complexes

Amination of PtII-allene complexes of the type cis[PtCl2(Me2Cue5fbCue5fbCHR)(PPh3)] gives the new four-membered C, N chelate aminoalkenyl complexes [PtC(ue5fbCMe2)CHRNMe2(PPh3)Cl]. These undergo ready insertion of carbon monoxide into the Cue5f8Pt σ-bond; the resulting acyl complexes are oxidized by hydrogen peroxide to aminoacidato complexes, and the free unsaturated β-aminoacids can be recovered in good yield by ligand displacement.

Catalytic dimerisation of olefins by a cationic platinum(II) complex

The new complex [Pt(MeCN)4][(BF4)2] catalyses the dimerisation of branched olefinic monomers in nitromethane solution.

Reactions of some methoxydienylplatinum(II) complexes with carbon monoxide

Abstract Carbon monoxide reacts readily with methoxydienylplatinum(II) complexes, but carbonyl insertion into the α-Ptue5f8C bonds does not occur; instead (chloro)(carbonyl) or (chloro)(methoxycarbonyl) complexes are formed, depending on the nature of the dienyl system.

A new effective method for the resolution of prochiral olefins : Stereoselective coordination in [PtCl3 (olefin)]− induced by crystallization

Crystallization of [PtCl3(olefin)]− [(S-C6H5CH(CH3)N(CH3)3]+ compounds (olefin = prochiral olefins) affords a single diastereoisomer through a second-order asymmetric transformation.

Addition reactions on co-ordinated olefinic ligands. Part 8. Platinum(II) complexes of 1,1 -dimethylallene and their reaction with amines. Molecular structure of the zwitterionic derivative dichloro-[1-(NN-diethylammoniomethyl)-2-methylprop-1-enyl](triphenylphosphine) platinum(II)

Some new platinum(II) complexes of 1,1-dimethylallene (dma) of general formula cis-[PtCl2(dma)L](L = PPh3, AsPh3, H2NC6H4Me-p, or SMe2O) have been prepared. They react with aliphatic and aromatic amines to give zwitterionic alkenyl derivatives of the type cis-[PtCl2(Me2CCCH2NR1R2R3) L], which on treatment with hydrogen chloride afford the ammonium salts [NR1R2R3(CH2CHCMe2)]Cl. The structure of the alkenyl complexes has been confirmed by X-ray diffraction analysis in the case of the title complex. Crystals are triclinic, space group P, with Z= 4 in a unit cell of dimensions a= 11.130(3), b= 18.887(5), c= 14.370(5)A, α= 108.8(3), β= 90.1(2), γ= 95.1 (2)°. The structure has been solved by Patterson and Fourier methods and refined by block-diagonal least-squares to R= 0.10 for 3 630 observed reflections. The σ-bonded alkenyl group is perpendicular to the metal co-ordination plane. A short intramolecular contact between the nitrogen and a chlorine atom suggest the existence of a hydrogen bond.