title: Studies of gas-phase fragmentation reactions of [Pd(PPh3)2(OCOR)]+ by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.
abstract: Gas-phase fragmentation reactions of [Pd(PPh3)2(OCOR)]+ (R = H, CH3, CD3, C2H5, n-C3H7, n-C6H13 and C6H5) were studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS). In sustained off-resonance irradiation collision-activated dissociation (SORI-CAD) experiments, the complexes all dissociated to yield the same product ion at m/z 629.1. We propose that the fragmentation pathway occurs through the elimination of RCOOH and a palladium(IV) hydride intermediate. Semi-empirical (PM3) calculations shed light on the mechanism for the fragmentation reactions of these compounds. The results of deuterium-labeling experiments indicate that the protons of RCOOH lost from [Pd(PPh3)2(OCR)]+ originate from the phenyl in the triphenylphosphine ligand. [Pd(PPh3)2(OCOH)]+ undergoes two competitive pathways in SORI-CAD experiments, one of which is similar to that of [Pd(PPh3)2(OCOR)]+ (R = CH3, CD3, C2H5, n-C3H7, n-C6H13 and C6H5), and the other involves decarboxylation. The present study demonstrates that MS could play an important role in studying the gas-phase chemistry of palladium hydrides.
authors.affiliation: Shanghai Mass Spectrometry Center, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, PR China.
authors.forename: Rong
authors.initials: R
authors.lastname: Qian
authors.forename: Hao
authors.initials: H
authors.lastname: Guo
authors.forename: Yuanxi
authors.initials: Y
authors.lastname: Liao
authors.forename: Haoyang
authors.initials: H
authors.lastname: Wang
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.forename: Yinlong
authors.initials: Y
authors.lastname: Guo