The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.1038-95-5, Name is Tri-p-tolylphosphine, molecular formula is C21H21P. In a Article，once mentioned of 1038-95-5, Recommanded Product: 1038-95-5
Complexes of the type a’s-[PtL2Me2] (1-14) (L = an extended series of phosphines of widely different steric and electronic properties) were synthesized, characterized, and used as precursors for the formation of cis-monoalkylplatinum(II) solvente species in methanol. The cleavage of the first platinum-alkyl bond by protonolysis is a fast process, but the subsequent cis to trans isomerization of the cationic solvento species [PtL2- (Me)(MeOH)]+ is relatively slow and it can be monitored using 31P NMR or conventional spectrophotometry. A large collection of 1H and 31P NMR data for cis-[PtL2Me2], cis-[PtL2Me(MeOH)]+, and trans-[PtL2Me(MeOH)]+ complexes showed interesting dependencies upon the size, the alpha-donor capacity, and the mutual position of the phosphines in the coordination sphere of the metal. The rate constants for isomerization of cis-[PtL2Me(MeOH)]+ were resolved quantitatively into steric and electronic contributions of the phosphine ligands, by means of correlations with parameters which reflect their sigma-donor ability (Chi values) and steric requirements (Tolman’s cone angles, theta). The electronic and steric profiles obtained for these reactions are discussed within the framework of a mechanism which involves dissociative loss of the solvent molecule and interconversion of two geometrically distinct 3-coordinate T-shaped 14-electron intermediates. The factors controlling the stability of these coordinatively unsaturated species are discussed. The electronic and steric influences of phosphines as “spectator” ligands in a dissociative process are compared with those shown by these ligands when used as nucleophiles in associative substitution processes. The activation parameters DeltaH? and DeltaS? were measured using both conventional isothermal and non-isothermal spectrophotometric kinetics.
Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.Recommanded Product: 1038-95-5, you can also check out more blogs about1038-95-5
Reference：
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate