The catalyst may temporarily changed though!
T1 - Rh 2(II)-catalyzed synthesis of carbazoles from biaryl azides
It does take a crucial part in the reaction and may be temporarily chemically changed, but the original catalyst does reform to perform its task again i.e.
T1 - Tetrahedral Sn-silsesquioxane
collision theory are repeated here, but with extra experimental methods and theoretical details applied to experiments and theories linked to the effect of using a catalyst on the rate of a chemical reaction
Lanosterol biosynthesis pathway, introduction.
Planar-chiral diphosphine (,)-4, having a η5-cyclopentadienylrhenium(I) tricarbonyl backbone was prepared by a sequence involving an enantioselective (CBS) reduction of acetylcyrhetrene 5 to give alcohol ()-6, several retentive SN1-type substitution reactions, and a diastereoselective introduction of the phosphino substituent at the cyclopentadienyl ring through directed -lithiation. The application of a palladium complex of (,)-4 in allylic alkylation reactions afforded a product with up to 88% ee. Use of (,)-4 in Rh-catalyzed hydrogenations of dimethyl itaconate and acetamidocinnamic acid gave enantioselectivities of up to 95 and 89% ee, respectively. Thus, in the catalyses cyrhetrenyl diphosphine (,)-4 compares well with its ferrocene-based analogue, Josiphos 1a. The ligand/metal binding mode of ,-cyrhetrene (,)-10 was revealed by the X-ray crystal structure analysis of complex [PdCl2·(,)-10]. The results of this study confirmed the expected structural similarities between the planar-chiral cyrhetrene and the analogous ferrocene and suggested a lower basicity of the former due to the electron-withdrawing property of its Re(CO)3 fragment. This structure-based analysis is in accord with the interpretation of the catalytic properties of metal complexes bearing cyrhetrenyl diphosphine (,)-4.