212317-70-9Relevant academic research and scientific papers
Solution behavior and X-ray structure of cationic allylpalladium(II) complexes with iminophosphine ligands. Kinetics and mechanism of allyl amination by secondary amines
Crociani, Bruno
, p. 1137 - 1147 (2008/10/08)
The solution behavior of the cationic complexes [Pd(η3-allyl)(P-N)]+ (P-N = o-(PPh2)C6H4-CH=NR (R = C6H4OMe-4, Me, CMe3, (R)-bornyl); allyl = propenyl (1a-4a) and 3-methyl-2-butenyl (1b-4b)) consists essentially of three dynamic processes: (i) a very fast conformational change of the P-N chelate ring, which moves above and below the P-Pd-N coordination plane, (ii) a relatively fast η3-η1-η3 interconversion which brings about a syn-anti exchange only for the allylic protons cis to phosphorus; (iii) a slower apparent rotation of the η3-allyl ligand around its bond axis. For 1b-3b, two geometrical isomers are observed, the predominant one having the allyl CMe2 group trans to phosphorus. The complexes 4a and 4b, containing the chiral (R)-bornyl group, are present in solution with two and four diastereomeric species, respectively.
Preparation and reactions of palladium(0)-olefin complexes with iminophosphine ligands
Antonaroli, Simonetta,Crociani, Bruno
, p. 137 - 146 (2007/10/03)
The complexes [Pd(η2-ol){o-(Ph2P)-C6H4-CH=NR}] [ol, dimethyl fumarate (dmf), 1,4-naphtoquinone (nq), fumaronitrile (fn); R=C6H4OMe-4, CMe3, Me, bornyl] can be prepared in good yields from the reaction of the allyl derivatives [Pd(η3-C3H5) {o-(Ph2P)-C6H4-CH=NR}]BF4 with an excess of NHEt2 in the presence of the activated olefin ol. The complex [Pd(η2-ma){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}] (ma, maleic anhydride) is more conveniently obtained via olefin substitution from [Pd(η2-dmf){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}]. The α-diimine ligand of [Pd(η2-fn)(py-2-CH=NC6H4OMe-4)] is quantitatively displaced by the appropriate iminophosphine to give [Pd(η2-fn){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}]. The new zerovalent complexes with P-N ligands are characterized by multinuclear NMR spectroscopy. In solution, olefin rotation or olefin exchange are generally slow. The compound [Pd(η2-fn){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}] reacts with a second molecule of iminophosphine yielding [Pd(η2-fn){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}2] in which the iminophosphines act essentially as P-monodentate ligands. [Pd(η2-dmf) {o-(Ph2P)-C6H4-CH=NC6H4OM e-4}] undergoes fast oxidative addition of allyl chloride to [Pd(η3-C3H5){o-(Ph2P)-C6H4-CH=NC6H4OMe-4}]+.
