Polynuclear derivatives

The polynuclear derivatives [ AuAg(C6F5)2L J [129, 130] were prepared by reacting the gold derivatives NBu4[Au(C6Fs)2] with Ag[C104], the polymeric complex... 

The presence of an excess of electron density on the carbon atom in methanide gold (III) complexes permits them to act as C-donor nucleophiles forming dinuclear or even polynuclear derivatives. 

Lopez-de-Luzuriaga, J.M. and Jones, P.G. (1993) Polynuclear derivatives of gold synthesis, structure, and reactivity. Special Publication Royal Society of Chemistry, 131, (Chemistry of the Copper and Zinc Triads), 168-171. 

Chiral bis-(binaphthophosphole) (bis(BNP)) ligands have been used in the asymmetric hydroformylation of styrene. In solution, the free diphospholes display fluxional behavior. Consistent with their structure, the reaction of the bis(BNP) compounds with platinum(II) derivatives gives either cis chelate mononuclear complexes or trans phosphorus-bridged polynuclear derivatives. Coordination to platinum enhances the conformational stability of bis(BNP)s and diastereomeric complexes can be detected in solution. In the presence of SnCl2, the platinum complexes give rise to catalysts that exhibit remarkable activity in the hydroformylation of styrene. Under optimum conditions, reaction takes place with high branched selectivity (80-85%) and moderate enantio-selectivity (up to 45% ee). 

The IR spectra of all of these compounds do not show absorptions due to bridging carbonyl groups, and the NMR spectra indicate that the hydrogen atoms are always in bridging positions. Future structural determinations of such an impressive series of polynuclear derivatives will make a considerable contribution to the chemistry of high nuclcarity clusters. Until now only the structures of Os6(CO) is and Os7(CO)2i have been determined (104). 

In the course of our research, which focused on the synthesis of pentachloro or pentafluorophenyl-containing Pd or Pt complexes, we developed synthetie procedures for the preparation of square-planar Pt(II) or Pd(II) anionic complexes i.e. palladate or platinate complexes) containing from one to four perhalophenyl groups per metal center. The study of the reactivity of these complexes revealed that because of their anionic nature, they have an excess of electron density around the metal center (probably located on the d orbital) and they can react with Lewis acids giving rise to neutral reaction products. When the Lewis acid is a metal complex or a metal salt, polynuclear derivatives with metal-metal bonds of a donor-acceptor nature are obtained. Most of the work presented in this account has been carried out by reacting the platinate substrates with silver derivatives, which afford polynuclear complexes containing Pt Ag bonds. Our first paper in this field ap-... 

Silyl enol ethers and ketene silyl acetals add to aromatic nitro compounds in the presence of TASF(Me) to give intermediate dihydro aromatic nitronates which can be oxidized with bromine or 2,3-dichloro-5,6-dicyano-l,4-benzoquinone to give a-nitroaryl carbonyl compounds the latter are precursors for indoles and oxindoles. The reaction is widely applicable to alkyl-, halo-, and alkoxy-substituted aromatic nitro confounds, including heterocyclic and polynuclear derivatives (eq 7). 

The hexanuclear platinum-copper complex Pt2Cu4(C6F5)4(C=C Bu)4(acetone)2] (320) and the polynuclear derivative [PtCu2(C6F5)2(C=CPh)2] c (321), which... 

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