Hydrides dihydrides

The halide groups can be replaced by other substituents like hydride or alkyl [86]. When the naphthyl (np) RuHnp(dmpe)2 is heated, the ligand undergoes an internal metallation to afford a dimer [87] (it was originally believed to be a monomer), though Ru(dmpe)2 has been isolated by photolysis of its dihydride, in matrixes at 12K (Figure 1.29) [88],... 

RhCl(PPhi)i as a homogenous hydrogenation catalyst [44, 45, 52]. The mechanism of this reaction has been the source of controversy for many years. One interpretation of the catalytic cycle is shown in Figure 2.15 this concentrates on a route where hydride coordination occurs first, rather than alkene coordination, and in which dimeric species are unimportant. (Recent NMR study indicates the presence of binuclear dihydrides in low amount in the catalyst system [47].)... 

Several m-platinum(II) dihydrides lose H2 reversibly in solution, forming dinuclear platinum(I) hydrides [(diphosphine)PtH]2 [62],... 

Bis-[pentafluor-phenyl]- -dibromid 486 Bis-[pentafIuor-phenyl]- -dihydrid 486 Dicblor-dipbenyl- 702 Diphenyl- 702 Propyl- -trichlorid 486 Propyl- -trihydrid 486 Tris-[pentafluor-phenyI]- -bromid 486 Tris-[pentafluor-phenyI]- -hydrid 486... 

Dibutyl- -dihydrid 34 Diphenyl- -dihydrid 34 Organo- -hydride Anwendung 34 Eigenschaften 34 markierte 34 Triathyl- -hydrid 33 Tributyl- -hydrid 33 Trimethyl- -hydrid 33 Triphenyl- -hydrid 33... 

The mixed halide-hydrides PhjSnHCl and PhjSnHBr have been prepared from the reaction of diphenyltin dihydride with the appropriate diphenyltin dihalides (274). 

Trimethyltin chloride reacts with carboxylic acids at 100° to give the corresponding chloride carboxylates Me2Sn(Cl)OCOR (187, 188), and diethyltin dihydride, triethyltin hydride, hexaethylditin, and bis(triethyltin) oxide have been shown to react with lead tetraacetate to give diethyltin diacetate or triethyltin acetate, as appropriate (189). 

In a modification of this method, the Sn-0 bonded compound can be generated in situ by partial acidolysis of a tin hydride, and, from the reaction between diphenyltin dihydride and carboxylic acids, a number of l,2-bis(acyloxy)-l,l,2,2-tetraphenylditins, (RC02)Ph2SnSnPh2(02CR) (e.g., R = CHj, CF3, PhaSi, or PhjGe), have been prepared (257, 258). 

The racemization mechanism of sec-alcohols has been widely studied [16,17]. Metal complexes of the main groups of the periodic table react through a direct transfer of hydrogen (concerted process), such as aluminum complexes in Meerwein-Ponn-dorf-Verley-Oppenauer reaction. However, racemization catalyzed by transition metal complexes occurs via hydrogen transfer processes through metal hydrides or metal dihydrides intermediates (Figure 4.5) [18]. 

Transition-metal catalyzed photochemical reactions for hydrogen generation from water have recently been investigated in detail. The reaction system is composed of three major components such as a photosensitizer (PS), a water reduction catalyst (WRC), and a sacrificial reagent (SR). Although noble-metal complexes as WRC have been used [214—230], examples for iron complexes are quite rare. It is well known that a hydride as well as a dihydrogen (or dihydride) complex plays important roles in this reaction. 

The related dihydride-dichloro complex OsH2Cl2(P Pr3)2 is also an active catalyst for the hydrogenation of olefins, diolefms, and a-(3-unsaturated ketones,14 but attempts to hydrogenate phenylacetylene show a rapid deactivation of the catalyst due to formation of a hydride-carbyne complex.54... 

The hydrogens within the octahedral olefin-dihydride intermediate are transferred consecutively with overall cis addition, and the rate-determining step (k9) is olefin insertion to give the alkyl- hydride. Kinetic and thermodynamic parameters for nearly all the steps of Fig. 1 have been estimated for the cyclohexene system. Because the insertion reaction is generally believed to require a cis disposition of the hydride and olefin... 

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