Catalytic Decarboxylative Coupling of Allyl Acetate: Role of the Metal Centers in the Organometallic Cluster Cations [CH₃Cu₂]⁺, [CH₃AgCu]⁺, and [CH₃Ag₂]⁺

Abstract

Metal-catalyzed decarboxylative coupling reactions offer new opportunities for formation of C−C bonds. Here, multistage ion trap mass spectrometry experiments together with DFT calculations are used to examine the role of the metal centers in coinage metal cluster catalyzed decarboxylative coupling of allyl acetate in the gas phase via a simple two-step catalytic cycle. In step 1, the metal acetate cluster cation [CH 3 CO 2 Cu 2 ] + , [CH 3 CO 2 AgCu] + , or [CH 3 CO 2 Ag 2 ] + is subjected to collision-induced dissociation to yield the organometallic cluster cation [CH 3 Cu 2 ] + , [CH 3 AgCu] + , or [CH 3 Ag 2 ] + , respectively.Step 2 involves subjecting these organometallic cluster cations to ion−molecule reactions with allyl acetate with the aim of generating 1-butene and re-forming the metal acetate cluster cations to close the catalytic cycle. Experiment and theory reveal the role of the two metal centers in both steps of the gas-phase catalytic reaction. All three metal acetates undergo decarboxylation (step 1), although when competing reactions are taken into account, the yield of [CH 3 Cu 2 ] + is highest (83.3%). Ion−molecule reactions of the organometallic cations with allyl acetate all proceed at the collision rate; however, the types of products formed and their yields vary considerably. For example, only [CH 3 Cu 2 ] + and [CH 3 AgCu] + undergo the C−C bond-coupling reaction (step 2) in yields of 52.7% and 1.2%, respectively. Overall the dicopper clusters are the superior decarboxylative coupling catalysts, since they give the highest yields of the desired products for both steps 1 and 2. These results highlight that the reactivity of organometallic coinage metal clusters can be "tuned" by varying the composition of the metal core.

Ambient preparation and reactions of gas phase silver cluster cations and anions

“…For larger clusters ([Ag 4 (CH 3 COO) 3 ] + and larger), dissociation (by CID) of the massselected ion is dominated by the loss of Ag 2 (CH 3 COO) 2 units, which likely occurs in two separate steps. 24 Smaller hydrated clusters undergo water loss followed by ejection of AgCH 3 COO while the cluster [Ag 2 (CH 3 COO)] + undergoes decarboxylation in agreement with observations by O'Hair et al 50 Negative ion mode electrospray produces a series of ions [Ag n-1 (CH 3 COO n )] -, which do not exhibit any geometric magic numbers ( Figure S4A). Dissociation of silver acetate cluster anions is by loss of Ag(CH 3 COO).…”

Gas‐phase functionalized carbon‐carbon coupling reactions catalyzed by Ni (II) complexes

“…We chose four acetate esters CH 3 COOR′ with various R′ groups. Allyl acetate has become almost a “standard” reagent in gas‐phase C―C coupling reactions and depending on the mechanism provides either a sp 2 or sp 3 carbon for coupling.…”

Phenyl-Group Exchange in Triphenylphosphine Mediated by Cationic Gold–Platinum Complexes—A Gas-Phase Mimetic Approach

“…The spectrum is measured ca. 5 min after mixing both components and shows the isotopolologues 1-d n (n = 0, 15,30,45,60). The broadening of the signals is explained further below.…”