R. Uson

Novel anionic gold(I) and gold(III) organocomplexes

Summary Tetrahydrothiophen (tht) and/or chloride may readily be displaced from ClAu(tht) with perhaloaryl lithium to give anionic complexes of the [R 2 Au] − or [RAuX] − type (R = C 6 F 5 or C 6 Cl 5 ; X = Cl or Br). Anionic gold(III) complexes can be prepared both by the reaction of Cl 3 Au-(tht) or K[AuCl 4 ] with LiC 6 F 5 or by the oxidative addition of halogens or (C 6 F 5 ) 2 TlBr to gold(I) complexes.

Pyrazolate bridged dinuclear rhodium complexes. X-ray structure of [Rh(Pz)(CO)P(OPh)3]2

Abstract The synthesis and properties of complexes of general formulae [Rh(Pz)(CO)L] 2 (Pz = pyrazolate ion, L = phosphorus donor ligand), [Rh(Pz)(diolefin)] 2 and [Rh(Pz)(C 2 H 4 ) 2 ] 2 are reported. The crystal structure of the novel complex [Rh(Pz)(CO)P(OPh) 3 ] 2 has been determined by X-ray methods. The crystals are triclinic, space group P 1 , with Z = 2 in a unit cell of dimensions a 14.061(10), b 17.140(13), c 9.937(7) A, α 102.19(7), β 10.9.55(8), γ 75.14(8)°. The structure has been solved by Patterson and Fourier methods and refined by full-matrix least-squares to R = 0.058 for 2514 independent observed reflections. The structure consists of discrete dimeric complexes in which each rhodium is in nearly square-planar arrangement, being bonded to a carbon atom of a carbonyl group, to a phosphorus of a triphenylphosphite ligand and to two nitrogen atoms of pyrazolate ligands bridging the metal atoms. The dihedral angle between the two square planes of 86.2° gives a bent configuration to the molecule in which the carbonyls and the phosphite ligands are in a trans arrangement.

Cationic palladium(II) complexes involving unprecedented O-coordination of acetylmethylenetriphenylphosphorane

Abstract Cationic pentafluorophenyl palladium(II) complexes of the type [Pd(C6F5)L2(APPY)]ClO4 (L = PPh3, PBu3n; L2 = bipy and A acetylmethylenetriphenylphosphorane) have been prepared by addition of APPY to the perchlorato complexes [Pd(OClO3)(C6F5)L2]; the APPY ligand is O-coordinated, which is unprecedented in keto-stabilized ylide complexes of palladium. The neutral complex Pd(C6F5)(Cl)(tht)(APPY) has been made by addition of APPY to the binuclear complex Pd2(μ-Cl)2(C6F5)2(tht)2 (tht = tetrahydrothiophene); in which the APPY ligand shows the normal C-coordination.

Dichloro-bis(pentafluorophenyl)(chelate) complexes of palladium(IV)

Abstract Four organometallic palladium(IV) complexes: Cl2(C6F5)2Pd(LL) (LL being a bidentate nitrogen-donor ligand) have been prepared by the oxidative addition of chlorine to the corresponding bis(pentafluorophenyl)palladium(II) complexes, (C6F5)2Pd(LL). Some of their properties are described.

Mono- and bi-nuclear anionic pentafluorophenyl complexes of palladium(II) and platinum(II)

The arylation of K2[MCl4], [MCl2(tht)2], MCl2, or [NBu4]2[M2(µ-Br)2Br4](M = Pd or Pt; tht = tetrahydrothiophen) with LiR or MgBrR (R = C6F5) leads to novel mono- and bi-nuclear anionic organo-derivatives of the general formulae [MR3(tht)]–, [MR4]2–, and [M2(µ-Br)2R4]2–, which have been isolated as tetra-alkylammonium salts. Reaction of compounds of the [MR3(tht)]– type with neutral ligands leads to the substitution of tht by L, that of [PdR4]2– with PdCl2 gives rise to the formation of [Pd2(µ-Cl)2R4]2–, whilst [M2(µ-X)2R4]2– reacts with alkali-metal salts of Br–, I–, or SCN– to give (without cleavage of the bridging system) the corresponding complexes. Twenty anionic complexes of these three novel types have been isolated and characterized.

Cationic rhodium(I) organic complexes with nitrogen donors and their carbonylation products

Abstract The preparation and properties of eleven new cationic rhodium(I) complexes with mono- and bi-dentate nitrogen donor ligands are described. Their carbonylation at normal pressure leads to the corresponding dicarbonyl compounds, in which one of the CO groups can be replaced by PPh 3 .

Gold complexes with heterocyclic thiones as ligands. X-Ray structure determination of [Au(C5H5NS)2]ClO4

Displacement of the weakly co-ordinating tetrahydrothiophene (tht) ligand in [AuX(tht)], [Au(tht)2]ClO4, or [Au(PPh3)(tht)]ClO4(X = Cl or C6F5) by heterocyclic thiones HL (HL = C3H5NS2, C4H4N2S, C5H5NS, C7H5NS2, or C7H6N2S), leads to the formation of neutral or cationic complexes of the types [AuX(HL)], [Au(HL)2]ClO4, or [Au(PPh3)(HL)]ClO4. For gold(III) complexes the tht ligand cannot be displaced but [Au(C6F5)3(OEt2)] reacts with HL to give neutral complexes [AuR3(HL)]. Deprotonation of the NH unit in the cationic complexes leads to neutral monomeric complexes and since the deprotonated N atom is now a donor, binuclear complexes can be prepared by displacement of a weakly co-ordinating ligand from other suitable complexes. The structure of [Au(HL)2]ClO4(HL = C5H5NS) has been established by X-ray crystallography [space group P, a= 9.609(3), b= 15.024(6), c= 16.712(7)A, α= 97.52(4), β= 104.17(2), γ= 104.76(2)°, and R′= 0.045 for 5 499 unique observed reflections]. The cations are arranged in a way that is unprecedented for gold(I) compounds. Five of the six cations in the cell are linked by short Au ⋯ Au contacts (3.3 A) and the sixth cation is monomeric.

Synthesis and reactivity of bimetallic Au–Ag polyfluorophenyl complexes; crystal and molecular structures of [{AuAg(C6F5)2(SC4H8)}n] and [{AuAg(C6F5)2(C6H6)}n]

The reaction of [NBun4][AuR2](R = C6F5 or C6F3H2-2,4,6) with Ag[ClO4] leads to complexes [{AuAgR2}n], which react with neutral ligands to give complexes [{AuAgR2L}n](L = neutral O-, N-, S- or P-donor ligand, alkene, or alkyne). For R = C6F5 and L = diphenylacetylene, the product is [{AuAgR2·0.5L}n]; the 0.5L can be displaced by other ligands, such as acetone, arenes, or alkenes, to reform [{AuAgR2L}n]. An X-ray diffraction study of [{AuAgR2L}n](R = C6F5, L = tetrahydrothiophene) reveals (AuAg)2 rings with Au–Ag 2.726 and 2.718 A(the first reported Au–Ag bond lengths), linked by Au ⋯ Au short contacts (2.889 A) to form infinite metal-atom chains. This complex crystallizes in space group Pccn, with a= 11.185(3), b= 22.475(6), c= 14.802(4)A, Z= 8, R= 0.041 for 2 005 reflections. The complex [{AuAgR2L}n](R = C6F5, L = benzene) crystallizes in space group C2/c, with a= 24.231(5), b= 7.570(1), c= 22.613(5)A, β= 117.49(2)°, Z= 8, and R= 0.035 for 3 008 reflections; it shows the same type of metal-atom chain (Au ⋯ Au 3.013; Au–Ag 2.702 and 2.792 A). The benzene ring is co-ordinated by one edge to silver. In both structures the gold atoms lie on a crystallographic two-fold axis.

Catalytic transfer hydrogenation by cationic rhodium(I) complexes

Summary Complexes formed by adding Group Vb ligands to [Rh(NBD) 2 ]ClO 4 in the presence of potassium hydroxide catalyze hydrogen transfer from isopropanol to acetophenone, cyclohexene and other unsaturated substrates. The catalytic activity depends upon the nature of the mono- or bidentate nitrogen-or phosphorus-donor ligands. [Rh(NBD) {P( p -MeOC 6 H 4 ) 3 }ClO 4 catalyses the selective reduction of hexyne or diolefins.

Synthesis and reactivity of perchlorate bis(tetrahydrothiophen)gold(I). 197Au Mössbauer spectra of three-coordinate gold(I) complexes

Abstract The displacement of tetrahydrothiophen (tht) in [Au(tht)2]ClO4 by neutral ligands gives bi-, tri- or tetra-coordinated complexes of the type [Au- (py)2]ClO4, [(tht)AuPPh2NHPPh2Au(tht)] (ClO4)2, [LAu(LL)]ClO4 (L=tht, PPh3; LL=bipy, phen) or [AuL4]ClO4 (L=PPh3, AsPh3 or SbPh3). The reaction between [Au(tht)2]ClO4 and (Bu4N)[AuR2] (R=C6F5, C6Cl5, C6F3H2) yields RAu(tht). The 197Au Mossbauer spectrum of [LAu(LL)]ClO4 establishes it as a tri-coordinated species, albeit with an asymmetrically linked bidentate ligand.