128168-43-4Relevant academic research and scientific papers
Equilibrium Studies of α-Diimine Displacement in Cationic Allylpalladium(II) Complexes by Monodentate N-Donors and the Mechanism of Allyl Amination by Triethylamine and Pyridine
Canovese, Luciano,Visentin, Fabiano,Uguagliati, Paolo,Bianca, Francesca Di,Antonaroli, Simonetta,Crociani, Bruno
, p. 3113 - 3118 (2007/10/02)
In the cationic complexes 3-allyl)(L-L)>ClO4 the chelated α-diimine was rapidly and reversibly displaced by secondary amines (N-methylaniline, morpholine or piperidine), triethylamine and 4-substituted pyridines.The observed equilibrium constants Ke increased with increasing basicity and decreasing steric requirements of the entering N-donor.They strongly depend on the α-diimine and decrease in the order RN=CHCH=NR RN=C(Me)C(Me)=NR ca.NC5H4(CH=NR)-2 (R = C6H4OMe-4).The cationic complex 3-C3H5)>(1+) underwent a slow allyl amination by triethylamine or pyridine (L') in the presence of fumaronitrile (fn), yielding 2-fn)> and Et3N(1+)CH2CH=CH2 or C5H5N(1+)CH2CH=CH2.Kinetic studies showed that the pseudo-first order rate constants for amination (kobs) are given by kobs = k2, suggesting a direct bimolecular attack of L' on the η3-allyl ligand.Amination hardly proceeds in the presence of the less-activated olefin dimethyl fumarate (dmf).The ?-accepting properties of the olefinic ligands play an important role also in the reaction of Et3N(1+)CH2CH=CH2 or C5H5N(1+)CH2CH=CH2 with 2-olefin)> (olefin = fn or dmf), i.e. the reverse of the amination reaction.
