Charge-Tagged Acetate Ligands As Mass Spectrometry Probes for Metal Complexes Investigations: Applications in Suzuki and Heck Phosphine-Free Reactions

Abstract

An acetate anion bearing an imidazolium cation as its charge tag was reacted with M(OAc)(2) complexes (where M = Ni, Cu, and Pd; in situ reaction) to form members of a new class of charge-tagged metal complexes. The formation of these unprecedented precatalysts with potential for cross-coupling reactions was confirmed by electrospray ionization (and tandem) mass spectrometry. The catalytic performance of the palladium complex was tested in Heck and Suzuki cross-coupling reactions, often with superior activity and yields as compared with Pd(OAc)(2).

The application of electrospray ionization mass spectrometry to homogeneous catalysis

“…A unique permanently-charged version of a self-assembling bidentate ligand (Figure 15) was synthesized to study the catalytic mechanism. Eberlin has reported a charge-tagged acetate ligand as a probe for mass spectrometry [88]. Nickel, copper, and palladium complexes of this ligand have been synthesized and characterized by ESI-MS (Scheme 15).…”

“…Observation of charge-tagged complexes generated in reaction of charged-tagged acetylene imidazolium salt with neutral M(OAc) 2 complexes (M = Cu, Ni, Pd)[88].A palladium-catalyzed system in which charged tags were used was recently reported by Schade et alThis study also includes examples of the use of charged quaternary ammonium-tagged substrates for studying Zn, Mg and In systems by ESI-MS and described some true reaction-monitoring experiments (vide infra)[89].…”

Analyzing the solution behavior of hygroscopic Imidazolium and Choline based ILs for optimizing liquid sorption media

“…[5][6][7][8][9][10][11] Subsequently the anion can be changed by an ion exchange column according to Alcalde et al (Chart 1). 12 To verify the completeness of the exchange we analyzed the NMR Spectra and perform a silver test.…”

Investigations of structure property relationships of highly hygroscopic Imidazolium and Choline based ILs for the prediction of thermodynamic trends

“…[8][9][10][11][12][13][14] Subsequently the anion can be changed by an ion exchange column according to Alcalde et al (Chart 1). 15 To verify the completeness of the exchange we analyzed the NMR Spectra and do a silver test.…”