The gas‐phase ligand exchange of copper and nickel acetylacetonate, hexafluoroacetylacetonate and trifluorotrimethylacetylacetonate complexes

Abstract

The gas-phase ligand-exchange reactions between Cu(II) and Ni(II) complexes containing the acetylacetonate (acac), hexafluoroacetylacetonate (hfac), and trifluorotrimethylacetylacetonate (tftm) ligands were investigated using a triple quadrupole mass spectrometer. The gas-phase mixed-ligand products of [Cu(acac)(tftm)](+), [Ni(acac)(tftm)](+), [Cu(hfac)(tftm)](+), and [Ni(hfac)(tftm)](+) were formed following the co-sublimation of either homo-metal or hetero-metal precursors. The gas-phase formation of [Cu(acac)(tftm)](+), [Cu(hfac)(tftm)](+), [Ni(acac)(tftm)](+), and [Ni(hfac)(tftm)](+) complexes is reported herein for the first time. The corresponding fragmentation patterns of these species along with those of Cu(tftm)(2) and Ni(tftm)(2) are also presented. Mass-selected ion-neutral reactions were investigated.

Electrospray mass spectrometric studies of nickel(II)-thiosemicarbazones complexes: Intra-complex proton transfer in the gas phase ligand exchange reactions

“…The mass difference (9 Da) of the two product ions is just equal to that of the two ESI solvent molecules. Therefore, the two product ions at m/z 299 and m/z 308 were ascribed to [Ni 2+ exchange reactions of metal complexes have been reported in the EI triple quadrupole [36], the quadrupole ion trap [37] and the ESI FT-ICR mass spectrometer [38]. The coordinative unsaturated metal complexes [26][27][28], some organic ions [39,40], and even halide anions [41] have been documented to undergo the gas-phase ion-molecule reactions with ESI solvent molecules to form adduct species in ion trap.…”

The gas‐phase ligand exchange reactions of cobalt and zinc acetylacetonate, hexafluoroacetylacetonate, and trifluorotrimethylacetylacetonate complexes

“…The mass distribution and fragmentation patterns for the aforementioned species are consistent with previously reported data, where there was an increased tendency for the investigated complexes to lose odd-electron fragments. [7,18,19] A two metal complex species, namely [Co 2 (acac) 3 ] + at m/z 415, was identified during these studies, yet played no observable role in mixed ligand formation.…”

“…In the Co, Cu, and Ni spectra, the reported relative abundance of the tBu signal is lower in comparison to the Zn spectra. [19] The mass spectra for the compounds previously described serve as reference spectra for comparing the homo-metal gas-phase reactions during co-sublimation. For example, the resulting mass spectra following the co-sublimation of Co(acac) 2 with Co(tftm) 2 is displayed in Fig.…”

“…[1][2][3][4] This unique class of compounds have been thoroughly investigated using mass spectrometry where fragmentation patterns have led to a better understanding of gas-phase reactivity as well as, more recently, identifying the prevalence of partial and complete gas-phase ligand exchange. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Our current approach utilizes mass spectrometry to exploit the volatility of various fluorinated acetylacetonate ligands in the formation of gas-phase mixed ligand complexes from hetero and homo transition metal precursors and to examine the role the metal center and ligands play in the ensuing gas-phase reactions. The fluorinated compounds, having a high volatility under mass spectrometric pressures and lower relative sublimation enthalpies compared to the corresponding neutral analogs, are used specifically to examine reactivity.…”

“…The proposed gas-phase reactions presented herein are consistent with earlier reports where the mixed ligand products were proposed to form during reactions in which the ion was represented by the more fluorinated species. [18,19]…”