P. W. Jolly

The preparation, reactions and structure of bis[bis(tricyclohexylphosphine)nickel] dinitrogen, {[(C6H11)3P]2Ni}2N2

Abstract The treatment of nickel acetylacetonate with trimethylaluminium in the presence of tricyclohexylphosphine and nitrogen gives the dinitrogen complex {[(C6H11)3P]2Ni}2N2 (I). Intermediate methyl-nickel complexes can be isolated, and provide an insight into the mechanism of formation of (I). The nitrogen molecule is readily displaced to give [(C6H11)3P]2Ni. The reactions of this coordinatively unsaturated species are described. The structure of the dinitrogen complex has been determined by X-ray crystallography from 5977 reflections using an automatic diffractometer, and refined anisotropically for all 80 atoms to a final R-value of 11%. The molecule is shown to contain a linear Ni-N-N-Ni system in which the nitrogen molecule is enclosed in a cage formed by four of the cyclohexyl rings. The NN bond distance is 1.12 A.

Transition metal allyls : IV. The (η3-allyl)2M complexes of nickel, palladium and platinum: reaction with tertiary phosphines

Abstract A series of 1 : 1 adducts have been prepared by treating the bis-η3-allyl complexes of nickel, palladium and platinum with tertiary phosphines. Investigations of their structure in solution as well as in the crystal have shown that both 18-electron (η3-allyl)2ML complexes as well as 16-electron (η1-allyl)-(η3-allyl)ML complexes may be formed.

Transition metal allyls ☆: III. The (η3-allyl)2M complexes of nickel, palladium and platinum: structural considerations

Abstract The structures of a series of (η 3 -allyl) 2 M complexes of nickel, palladium and platinum have been investigated with the help of 13 C NMR, 1 H NMR and Raman spectroscopy. The crystal structure of (η 3 -cyclooctatrienyl) 2 Ni has been determined by X-ray methods; the two nickel-bonded η 3 -allyl groups are mutually trans .

The palladium catalyzed reaction of carbon dioxide with allene

Abstract In the presence of a bis (η 3 -allyl)palladium-bisdicyclohexylphosphinoethane catalyst allene and CO 2 cooligomerize to give a mixture of esters, a lactone and polymer.

Transition metal allyls. VI: The stoichiometric reaction of 1,3-dienes with ligand modified zerovalent-nickel systems

Abstract Butadiene and methyl substituted 1,3-dienes react with zerovalent-nickel-ligand complexes in a stoichiometric manner to give octadienediylnickel-ligand complexes. The structure, rearrangement and reactions with CO and P-donor ligands of these species have been studied with the help of 1 H and 13 C NMR spectroscopy. The results provide an insight into the mechanism of the nickel-catalysed cyclodimerization of 1,3-dienes.

A FACILE ACCESS TO CPCR(ACAC)CL AND RELATED SYSTEMS

Abstract CpCr(acac)Cl has been prepared by reacting CpCr(THF)Cl2 with sodium acetylacetonate. Related Cr compounds containing the C5Me5 group and ethylacetoacetate have also been studied. Catalysts active for the polymerization of ethylene are obtained by treating these compounds with aluminium alkyls while the title compound reacts with Et2AlCl or Et3Al to give [CpCr(μ-Cl)Et]2.

The insertion of the dioxides of carbon and sulphur into the palladium-carbon bond

Abstract Bis ( η1, η2-allyl) palladium phosphine complexes react with carbon dioxide and sulphur dioxide by insertion into the palladium-carbon σ-bond to give η3-allylpalladium-carboxylate and -S-sulphinate complexes.

The structure of a model intermediate for the nickel-catalyzed cyclodimerization of allene

Abstract The stoichiometric reaction between allene, zerovalent nickel and a chelating diphosphane leads to the formation of a bis-methylenenickelacyclopentane derivative whose structure has been established by X-ray crystallography.

η3-Allyl complexes of molybdenum—IV. Preparation and crystal structures of some substituted-cyclopentadienyl molybdenum allyl derivatives

Abstract A series of substituted-cyclopentadienyl molybdenum allyl derivatives has been prepared by reacting (η 3 -C 3 H 5 ) 3 MoCl with substituted-cyclopentadienyl and -indenyl alkali metal salts. In general, the isolated products are of the type Cp′Mo(η 3 -C 3 H 5 ) 2 and in three cases this has been confirmed by crystal structure determinations. Spectroscopic evidence suggests that at low temperatures compounds have the composition Cp′Mo(η 3 -C 3 H 5 ) 2 (η 1 -C 3 H 5 ) are also formed. The reaction with potassium fluorenyl is anomalous: the NMR spectra and a crystal structure determination show that the product (η 3 -fluorenyl)Mo(η 3 -C 3 H 5 ) 3 , contains four η 3 -allyl groups bonded unsymmetrically to the metal atom.

Intermediates in the palladium-catalysed reaction of 1,3-dienes Part 8. The reaction of palladium-butadiene complexes with ethyl methylacetoacetate

Abstract The catalytic reaction of 1,3-butadiene with ethyl methylacetoacetate in the presence of (η 2 -1,3-butadiene)Pd(R 2 P(CH 2 ) n PR 2 ) compounds has been investigated. The product is a mixture of 1:1 adducts and the rate of reaction is highest when n 2, RPr i and in dichloromethane as solvent. Insight into the mechanism has been obtained by studying the stoichiometric reaction of (η 2 -1,3-butadiene)Pd(Pr i 2 PC 2 H 4 PPr i 2 ) with the ester using variable temperature NMR spectroscopy and it has been shown that initially an [(η 3 -1-MeC 3 H 4 )-Pd(Pr i 2 PC 2 H 4 Ppr i 2 )] + species is formed which reacts further to give (η 2 -alkene)Pd(Pr i 2 PC 2 H 4 Ppr i 2 ) compounds in which the product of the catalysis is complexed to the palladium atom. The crystal structures of three side products, viz. Pd 2 (Pr i 2 PCH 2 PPr i 2 ) 2 , [(η 1 ,η 3 -C 8 H 12 )Pd] 2 (Me 2 PC 2 H 4 PMe 2 ) and ClCH 2 Pd(Cy 2 PC 2 H 4 PCy 2 )Cl, have been determined by X-ray diffraction.