333-23-3Relevant academic research and scientific papers
Intramolecular Halogen Transfer via Halonium Ion Intermediates in the Gas Phase
Chai, Yunfeng,Xiong, Xingchuang,Yue, Lei,Jiang, You,Pan, Yuanjiang,Fang, Xiang
, p. 161 - 167 (2015/12/30)
The fragmentation of halogen-substituted protonated amines and quaternary ammonium ions (R1R2R3N+CH2(CH2)nX, where X = F, Cl, Br, I, n = 1, 2, 3, 4) was studied by electrospray ionization tandem mass spectrometry. A characteristic fragment ion (R1R2R3N+X) resulting from halogen transfer was observed in collision-induced dissociation. A new mechanism for the intramolecular halogen transfer was proposed that involves a reactive intermediate, [amine/halonium ion]. A potential energy surface scan using DFT calculation for CH2-N bond cleavage process of protonated 2-bromo-N,N-dimethylethanamine supports the formation of this intermediate. The bromonium ion intermediate-involved halogen transfer mechanism is supported by an examination of the ion/molecule reaction between isolated ethylenebromonium ion and triethylamine, which generates the N-bromo-N,N,N-triethylammonium cation. For other halogens, Cl and I also can be involved in similar intramolecular halogen transfer, but F cannot be involved. With the elongation of the carbon chain between the halogen (bromine as a representative example) and amine, the migration ability of halogen decreases. When the carbon chain contains two or three CH2 units (n = 1, 2), formal bromine cation transfer can take place, and the transfer is easier when n = 1. When the carbon chain contains four or five CH2 units (n = 3, 4), formal bromine cation transfer does not occur, probably because the five- and six-membered cyclic bromonium ions are very stable and do not donate the bromine to the amine.
Solid-state and Solution Structures of Fluorocholine and Some Analogues: Nuclear Magnetic Resonance and X-Ray Studies
Birdsall, Nigel J. M.,Partington, Peter,Datta, Narayandas,Mondal, Panchali,Pauling, Peter J.
, p. 1415 - 1418 (2007/10/02)
The preferred conformation of fluorocholine (CH3)3-N+-CH2-CH2-F and several analogues in aqueous solution has been determined by n.m.r. spectroscopic analysis and the crystal structure of (CH3CH2)3N+-CH2-CH2-F.Br- determined.The preferred conformation of N+-C-C-F is clearly synclinal.In comparison, that of N+-C-C-O- has previously been shown also to be synclinal and that of N+-C-C-S- and N+-C-C-Se- to be antiplanar.
