Comparison of laser-desorption and fast-atom-bombardment mass spectra of a series of rhodium Rh(PPh3)2(CO)Y complexes

Abstract

Abstract : The mass spectra of a series of involatile Rh(PPh3)2(CO)Y complexes (anion Y(-) is F(-), Cl(-), I(-), -NCO(-), -NCS(-), O2CCH3(-), ONO2(-), O2PF2(-) , or OSO2CF3(-); Rh(PPh3)2(CO) is shortened to RhL2CO hereafter) were obtained using both laser desorption Fourier-transform ion cyclotron resonance (LDFTICR) and fast atom bombardment (FAB) techniques. The FAB positive ion spectra (sulfolane matrix) showed molecular ions for all complexes except RhL2COOSO2CF3, which contained the most weakly-coordinating anion. These FAB spectra also exhibited fragment ions resulting from loss of CO and PPh3. The sulfolane adduct of RhL2CO(+) and a derivative were also observed for the series, especially prominent in spectra of complexes of the less tightly-bound anions. The LDFTICR positive-ion spectra were less consistent in fragmentation/rearrangement patterns over the range of anions Y(-) than were their FAB counterparts; peak intensities of the former spectra were also highly variable due to difficulties in preparing consistent probe samples. Keywords: Rh(PPh3)3(CO)Y Complexes, Laser desorption, Fourier transform ion cyclotron resonance mass spectrometry, Fast atom bombardment, Involatile compounds, Rhodium, Transition metals.