The preparation of hydridopentammine- and hydridoaquotetramminerhodium(III) sulphates and other salts; the formation of alkyl and fluoroalkyl derivatives

Thomas, K. R. Justin; Osborn, John A.; Powell, A. R.; Wilkinson, Geoffrey

doi:10.1039/j19680001801

Cited by 40 publications

(27 citation statements)

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“…The positions of these modes are similar to the values of ν M-H reported for hydrogen on supported particles of platinum 52,53 and for organorhodium complexes incorporating hydrides 54,55 (Table 5). To test the inference of hydrides, we attempted an exchange experiment with D 2 immediately following ethene hydrogenation catalysis on Rh 6 /La 2 O 3 .…”

Section: Synthesis Of Rh 6 Clusters Supported Onsupporting

confidence: 78%

Hexarhodium Clusters on Lanthana: Synthesis, Characterization, and Catalysis of Ethene Hydrogenation

et al. 2004

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Rhodium carbonyl clusters were prepared on the surface of La 2 O 3 powder (calcined at 673 K) by a surfacemediated synthesis from La 2 O 3 -supported Rh(CO) 2 (acac) in the presence of CO at 1 atm and 373 K. The cluster preparation and subsequent decarbonylation by treatment in He were characterized by infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies. Treatment in He at 573 K removed the carbonyl ligands, giving site-isolated La 2 O 3 -supported clusters that are well approximated as Rh 6 octahedra, being characterized by a first-shell Rh-Rh coordination number of 3.9 ( 0.4 at a distance of 2.64 ( 0.02 Å. The supported clusters were characterized by IR and EXAFS spectroscopies in the presence of ethene and H 2 reacting catalytically to give ethane. The EXAFS first-shell Rh-Rh coordination number was found to be about 4, consistent with the presence of Rh 6 octahedra, which are inferred to be the catalytically active species. IR spectra show that both hydrocarbons and hydride ligands were present on the working cluster catalyst, including π-bonded ethene and others, inferred to be ethyl, ethylidyne, and di-σ-bonded ethene. The concentration of hydride on Rh 6 increased during the initial induction period in a flow reactor as the catalytic activity increased almost proportionately; hydrides are inferred to be reactive intermediates. 1 H NMR spectroscopy showed that hydride remained on the clusters following catalysis. The results suggest that the hydrogenation of ethene on Rh 6 /La 2 O 3 proceeds by insertion of π-bonded ethene into a Rh-H bond to form ethyl, which is subsequently hydrogenated to give ethane. Rh 6 /La 2 O 3 is about 50 times more active for ethene hydrogenation catalysis than Rh 6 /γ-Al 2 O 3 , and we suggest that the difference is related to the electron-donor properties of the supports.

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Section: Synthesis Of Rh 6 Clusters Supported Onsupporting

confidence: 78%

Hexarhodium Clusters on Lanthana: Synthesis, Characterization, and Catalysis of Ethene Hydrogenation

et al. 2004

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“…In fact, zinc reduction of (N 4 )Rh(H 2 O) 2 3+ (N 4 = (NH 3 ) 4 , L 1 , L 2 ) is the best preparative route to rhodium hydrides. 16,18 Instead, solutions of (N 4 )(H 2 O)Rh 2+ must be prepared in chemical reactions, such as hydrogen atom abstraction from the hydride. Thus, by necessity and design, solutions of Rh(II) are not pure; they contain various added reagents and their products.…”

Section: Rhodium(ii)mentioning

confidence: 99%

Aqueous rhodium(iii) hydrides and mononuclear rhodium(ii) complexes

Bakač

2006

Dalton Trans.

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In aqueous solutions, as in organic solvents, rhodium hydrides display the chemistry of one of the three limiting forms, i.e. {Rh(I)+ H+}, {Rh(II)+ H.}, and {Rh(III)+ H-}. A number of intermediates and oxidation states have been generated and explored in kinetic and mechanistic studies. Monomeric macrocyclic rhodium(II) complexes, such as L(H2O)Rh2+ (L = L1 = [14]aneN4, or L2 = meso-Me6[14]aneN4) can be generated from the hydride precursors by photochemical means or in reactions with hydrogen atom abstracting agents. These rhodium(II) complexes are oxidized rapidly with alkyl hydroperoxides to give alkylrhodium(III) complexes. Reactions of Rh(II) with organic and inorganic radicals and with molecular oxygen are fast and produce long-lived intermediates, such as alkyl, superoxo and hydroperoxo complexes, all of which display rich and complex chemistry of their own. In alkaline solutions of rhodium hydrides, the existence of Rh(I) complexes is implied by rapid hydrogen exchange between the hydride and solvent water. The acidity of the hydrides is too low, however, to allow the build-up of observable quantities of Rh(I). Deuterium kinetic isotope effects for hydride transfer to a macrocyclic Cr(v) complex are comparable to those for hydrogen atom transfer to various substrates.

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“…Formation of sulfone, (CH,),SO,, was not detected. In degassed water, the complexes rapidly disproportionate to Rh metal and a green filtrate likely containing Rh(I1) (37,38). Lack of a terminal v(Rh-C1) and the analytical data are again the criteria used for dimer forrnulation of the Rh(Q complexes.…”

Section: Diphenyisulfoxide Complexesmentioning

confidence: 99%

Sulfur-bonded sulfoxide complexes of rhodium(III) and rhodium(I)

James¹,

Morris²

1980

Can. J. Chem.

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Aqueous 2-propanol solutions of RhCl3•3H2O on treatment with sulfoxides yield mer-RhCl3L3 complexes, the sulfoxide L being dimethyl (DMSO), tetramethylene (TMSO), methyl phenyl (MPSO), or (R)-methyl-p-tolyl (MPTSO); with diphenyl sulfoxide (DPSO), a [RhCl(DPSO)2]2 complex with S-bonded sulfoxide is obtained via the propanol reduction of a Rh(III) intermediate. The mer-rhodium(III) complexes in solution contain two sulfur-bonded sulfoxides (R2SO), and one oxygen-bonded sulfoxide (R2SO) that is trans to a (R2SO) ligand. The DMSO ligand in mer-RhCl3(DMSO)2(DMSO) is displaced by amides, amine oxides, and phosphine oxides; the DMSO cis to the oxygen-bonded ligands is identified in nmr by using the ring current shielding effects of OPPh2Me. Salts of [RhCl4(R2SO)2]− have been obtained with n-propyl sulfoxide and DMSO using several cations, including the symmetrically hydrogen-bridged species, [R2SO—H—OSR2]+. The cyclooctene precursor [RhCl(C8H14)2]2 has been used to synthesize [RhCl(DPSO)(C8H14)]2, [RhCl(DMSO)2]2, and [RhCl(DIOS)2]2, where DIOS is (2R,3R)-2,3-isopropylidene-2,3-dihydroxy-1,4-bis(methylsulfinyl)butane. The nature of rhodium–sulfur bonding is discussed, especially in terms of a contribution of metal–sulfur π-backbonding.

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The preparation of hydridopentammine- and hydridoaquotetramminerhodium(III) sulphates and other salts; the formation of alkyl and fluoroalkyl derivatives

Cited by 40 publications

References 0 publications

Hexarhodium Clusters on Lanthana: Synthesis, Characterization, and Catalysis of Ethene Hydrogenation

Hexarhodium Clusters on Lanthana: Synthesis, Characterization, and Catalysis of Ethene Hydrogenation

Aqueous rhodium(iii) hydrides and mononuclear rhodium(ii) complexes

Sulfur-bonded sulfoxide complexes of rhodium(III) and rhodium(I)

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