title: Fragmentation of pentacoordinate spirobicyclic aminoacyl-phosphoranes (P-AAs) by electrospray ionization tandem mass spectrometry concerning P-O and P-N bond cleavage.
abstract: The fragmentation pathways of both protonated and sodiated pentacoordinate spirobicyclic aminoacylphosphoranes (P-AAs) have been studied by electrospray ionization multi-stage mass spectrometry (ESI-MS(n)) in positive mode. The possible pathways and their mechanisms are elucidated through the combination of ESI-MS/MS, isotope ((15)N and (2)H) labeling and high-resolution Fourier transform ion cyclotron resonance (FTICR)-MS/MS. The relative Gibbs free energies (ΔG) of the product ions and possible fragmentation pathways are estimated at the B3LYP/6-31 G(d) level of theory. The theoretical calculations show that both protonated and sodiated P-AAs would quickly fragment before Berry pseudorotation. For protonated P-AAs, they have different tendencies to P-O or P-N bond cleavage. For sodiated P-AAs, the P-N bond is easier to cleave and produces the tetracoordinated phosphorus ion H. These results to some extent may give a clue to the chemistry of the active sites of phosphoryl transfer enzymes and will enrich the gas-phase ESI-MS ion chemistry of pentacoordinate phosphoranes.
authors.affiliation: Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Hu
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Zeng
authors.forename: Xinghua
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Lin
authors.forename: Pengxiang
authors.initials: P
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yufen
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D005583:Fourier Analysis; D010753:Phosphoranes / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013141:Spiro Compounds / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013816:Thermodynamics
chemical_list: D010753:Phosphoranes; D013141:Spiro Compounds