Charge-tagged ligands: useful tools for immobilising complexes and detecting reaction species during catalysis

Abstract

A critical overview is presented on the use of charged tagged ligands (CTLs) as immobilising agents in organometallic catalysis and as probes for studying mechanisms through electrospray ionisation mass spectrometry (ESI-MS) based on the most recent literature.

Heck Reaction—State of the Art

“…Recently, Limberger et al [106] have published a review on charge-tagged ligands, where there is an insertion of an ionic side chain into the molecular skeleton of a known ligand. This technique has become a useful protocol for anchoring ligands, and consequently catalysts, in polar and ionic liquid phases.…”

On-line monitoring of Soxhlet extraction by chromatography and mass spectrometry to reveal temporal extract profiles

“…This effect may be due to the ion suppression caused by the chemical complexity of the extract and the presence of numerous ionogenic species in the sample. This is in contrast to the application of ESI-related approaches in reaction monitoring [44][45][46][47][48][49], where chemical composition of the reaction mixture is not expected to change as much as in the case of extraction of biological samples.…”

Mechanistic insights from mass spectrometry: examination of the elementary steps of catalytic reactions in the gas phase

“…In terms of how to conduct these experiments successfully, we have covered the practical aspects -especially as practiced in our own laboratory -in a recent review [1]. The review covers issues such as cross-contamination, avoiding aggregation [2], protection from oxygen and water [3], ensuring the softest possible ionization [4], analysis in non-polar solvents such as toluene and hexane [5], selection of counter-ions and the design of charged tags [6,7], and the pressurized sample introduction method for continuous reaction monitoring [8]. Readers interested in these issues should sample the appropriate papers or go straight to the review for an overview of the problems and solutions.…”