Single and multiple insertion of alkynes into Pd-acyl and Pd-aryl bonds in cationic palladium complexes with phosphine-imine (P∼N) ligands
Journal
Organometallics
Journal Volume
20
Journal Issue
26
Pages
5557-5563
Date Issued
2001
Author(s)
Abstract
Neutral and cationic Pd(II)-alkyl and Pd(II)-aryl complexes with phosphine-imine (P∼N) ligands show unusual reactivity toward alkynes. No insertion of alkyne has been observed into the neutral palladium complexes or the cationic Pd-alkyl complex. On the other hand, smooth insertion of alkynes into the cationic complexes [(P∼N)Pd(COMe)(MeCN)]+ (4) and [(P∼N)Pd(Ph)(MeCN)]+ (5) was observed, resulting in the formation of single- and double-insertion products, respectively. All the inserted products were isolated and characterized by spectroscopic methods. Single-crystal X-ray analyses for some alkyne insertion complexes indicate that the products are stabilized by intramolecular coordination via either a carbonyl oxygen or a π-phenyl coordination with η2 mode. Higher order insertions of ethyl propiolate in the complexes [(P∼N)Pd(Ph)(MeCN)]+ (5) and [(P∼N)Pd(C(Ph)=C(Ph)C(Ph)=CPh2)(MeCN)]+ (13) leading to the oligomeric species are found to proceed smoothly, but disubstituted alkynes such as diphenylacetylene do not undergo such insertion.
SDGs
Type
journal article