Charge-transfer spectra of some complexes of ruthenium, rhenium, osmium, iridium, and platinum halides with tertiary phosphines and tertiary arsines

1970 ◽  
pp. 587 ◽  
Author(s):  
G. J. Leigh ◽  
D. M. P. Mingos
Keyword(s):  
Charge Transfer ◽  
Tertiary Phosphines ◽  
Tertiary Arsines

Studien zum Vorgang der Wasserstoffübertragung, 71 [1] Tertiäre Phosphine mit ortho-ständigen chelatisierungsfähigen funktionellen Gruppen als Co-Katalysatoren der Homogenhydrierung mit Rh(I)-Komplexen/Studies on the Occurrence of Hydrogen Transfer, 71 [1] Tertiary Phosphines with Functional Groups in the ortho-Position Capable for Chelatization as Co-Catalysts of the Homogeneous Hydrogenation with Rh(I)-Complexes

1984 ◽  
Vol 39 (4) ◽  
pp. 504-511 ◽  
Author(s):  
Leopold Horner ◽  
Guido Simons
Keyword(s):  
Hydrogen Transfer ◽  
Phenyl Group ◽  
Steric Effects ◽  
Ortho Position ◽  
Homogeneous Hydrogenation ◽  
Compound A ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Tertiary Phosphines ◽  
Tertiary Arsines

By systematic variation of the structure of tertiary phosphines with ortho-phenyl substituted groups as co-catalysts of the homogeneous hydrogenation with Rhodium complexes and hexene-1 as a model compound a collection of data is obtained. By investigating the influence of the variation of the Rhodium/Phosphine-Ratio (Rh/P) (1:1,1 and 1:2,2) on the rate of the hydrogentransfer indirect conclusion can be drawn on the composition of the complexes in the equilibria responsible for the hydrogen transfer.Results: 1. Steric effects of substituents linked to the ortho-position of a phenyl group in the co-catalyst are very important (compare the Tables I-V especially Table VI).2. The rate of hydrogenation is strongly influenced by tertiary phosphines with substituents in a ortho-phenyl group capable for coordination like NR2 and SR. With Rh/P = 1:1,1 the rate of the hydrogenation of hexene-1 is mostly faster as with Rh/P = 1:2,2. Depending on steric effects the rate data can be invers.3. Tertiary arsines with o-dialkylaminophenyl groups are more effective co-catalyst as the corresponding phosphines (Table V).4. Tertiary phosphines with an ortho-alkylmercaptophenyl group (38-41) are weakly active cocatalysts using Rh/P = 1:1,1.The thioether 42 (in compounds 12 the diphenylphosphino group is exchanged by the methylmercapto group) is also a moderate active co-catalyst.5. As a conclusion: it is assumed that complexes of the structure A can coordinate with the substrates hydrogen and olefine . Complexes of the structure B seen to be to stable for the activation of the substrates.

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