Understanding Gold‐Alkyne Activation from Bond Dissociation Energies of Gold‐Alkyne Complexes

• Published in: European journal of organic chemistry Vol. 27; no. 29
• Main Authors: Gatineau, David, Lesage, Denis, Guéret, Rodolphe, Mador, Samuel Danladi, Milet, Anne, Gimbert, Yves
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 05-08-2024; Wiley-VCH Verlag
• Subjects: Alkynes; Bonding strength; Cascade chemical reactions; Chemical bonds; Chemical Sciences; Electronic properties; Gold; Inorganic salts; ion-molecule reaction; ligand effects; Ligands; Mass spectrometry; organometallic; reactivity; tandem mass spectrometry; Vapor phases
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202400340

A detailed approach into electronic effects of ligands on gold‐alkyne interactions has been carried out in the gas phase using tandem mass spectrometry. A semi‐empirical method coupled to DFT calculations was used to quantify ligands effects on Au−CC bond strength. To this end, the critical energies of 16 [L−Au‐hex‐3‐yne]+ complexes with different L ligands were determined through collision induced dissociation. It was observed that electron‐rich ligands destabilize the gold‐alkyne bond, whereas phosphites and carbenes strengthened it. The influence of alkyne electronic effects on the gold‐alkyne bond has also been studied by dissociation in tandem mass spectrometry on four different alkynes. In an original approach, two successive ion‐molecule reactions within the mass spectrometer were used to measure the relative affinity of gold to an alkyne by exchange reactions. The result is that the more electron‐rich the alkyne, the stronger the gold‐alkyne bond.
The ligand effect has been intensively studied on gold(I)‐alkyne complexes bearing ligands commonly used in gold catalysis. The bond dissociation energy (BDE) of gold‐alkyne interactions has been realized by energy resolved collision induced dissociation (CID). This work is expected to contribute to understanding the alkyne activation in homogenous gold catalysis.