Gold(I) and Silver(I) π-Complexes with Unsaturated Hydrocarbons

Abstract

Gold π-complexes have been studied largely in the past 2 decades because of their role in gold-catalyzed reactions. We report an experimental and theoretical investigation of the interaction between a wide range of unsaturated hydrocarbons (alkanes, alkynes, alkadienes, and allenes) and triphenylphosphinegold(I), triphenylphosphine-silver(I), and acetonitrile-silver(I) cations. The bond dissociation energies of these complexes were determined by mass spectrometry collision-induced dissociations and their structures were studied by density functional theory calculations and infrared photodissociation spectroscopy. The results show that with the same phosphine ligand, gold binds stronger to the π-ligands than silver and thereby activates the unsaturated bond more effectively. Ligand exchange of phosphine by acetonitrile at the silver complexes increases the binding energy as well as the activation of the π-ligands. We also show that the substitution of an unsaturated bond is more important than the bond type.

Binding Interactions in Copper, Silver and Gold π‐Complexes

“…Previously, we have investigated binding energies of unsaturated hydrocarbons to phosphinogold(I) and phospinosilver(I) ions. [23] The binding energies to alkenes and alkynes were in the range of 1.8–1.9 eV for [Au(PMe 3 )(π‐ligand)] + and in the range of 1.6–1.8 for [Au(PPh 3 )(π‐ligand)] + . [24] In general, the binding energies were always about 0.1 eV higher for alkynes than for alkenes.…”

Cation‐π Interactions between a Noble Metal and a Polyfunctional Aromatic Ligand: Ag+(benzylamine)

“…A complete list of vibrational modes pertaining to all three BAÀ Ag_1-3 isomers is provided in Table S1. (10) ring breathing 1585 (43) sciss NH 2…”

“…[29,30] In a recent report, cation-π complexes of Ag + with benzene, toluene and furan have been studied with ultraviolet laser photodissociation and photofragment imaging, providing new information on the cation-π bond energies. [31] IR ion spectroscopy has proven to be a valuable tool to shed light on the structural features of complexes of the noble metals silver, [17,[32][33][34][35][36][37][38][39][40] gold [41][42][43][44][45][46] and platinum, [47][48][49][50][51][52][53] with a variety of ligands yielding a wealth of valuable information such that only partial reference may be given here. It has been reported that complexation of Ag + with polycyclic aromatic hydrocarbons is accompanied by substantial charge transfer, emerging from the analysis of the IR bands of the complexes compared to those of the bare ligands.…”

Silver cation tagged on 5,7,12,14-tetraphenyl-6,13-diazapentacene and its dihydro-form

“…The present study investigates the Ag + complexes of 5,7,12, 14-tetraphenyl-substituted 6,13-diazapentacene and its reduced 6,13-dihydro counterpart. 12,13 The motivation for this work originates from the importance of the silver(I) cation for the ion formation of unsaturated hydrocarbons [14][15][16][17][18][19][20][21][22] and, in particular, polycyclic aromatic hydrocarbons (PAHs) [23][24][25][26][27] which enables the application of electrospray ionization mass spectrometry (ESI-MS) for the analysis of these compounds. [28][29][30][31] ESI is one of the most important mass spectrometry-based methods for the analysis of molecules.…”