- HALOGENATION OF TRIS(ARYLAMINO)PHOSPHAZOBENZENES
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Mild selective replacement of the hydrogen atoms by halogens in the para position of all four benzene rings occurs in the action of halogens (Br, I) on tris(arylamino)phosphazobenzenes.Electrophilic substitution reactions in phosphazobenzenes proceed cons
- Kostina, V. G.,Rutkovskii, E. K.,Feshchenko, N. G.
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p. 767 - 770
(2007/10/02)
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- THIONO COMPOUNDS. 9. USE OF SPECTRA TO STUDY INTERMEDIATES IN THE OXIDATION OF THIONO PHOSPHORUS COMPOUNDS
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Intermediates in the oxidation by m-chloroperoxybenzoic acid (MCPBA) of 13 structurally different thiophosphoramides and phosphorothioates were studied at -25 deg C to 0 deg C using NMR, EPR, UV, IR and Raman spectra.The lifetimes of intermediates ascertained by NMR varied from a few minutes to many hours at the same temperature and were longer for thiono esters than for amides, for aryl than for alkyl constituents, and for electron-donating substituents on aryl groups than for electron-withdrawing groups.The major 31P NMR peaks for all intermediates appeared in the same region, about midway between the resonances of the P(S) starting materials and the P(O) products, indicating close structural similarly to one another for the intermediates; the range of 13-33 ppm for the major peaks indicates that the intermediates are tetracoordinate and supports phosphonium polysulfide structures for them of the type R3PSx (26, Scheme 1), or perhaps R3POSx.UV spectra also afforded support for polysulfide structures, since typical absorption develops and then disappears.Raman, 31P NMR, and UV spectra are consistent with longer-term presence of bisphosphonium species (e.g. 25, from reactions of 26; Scheme 1).EPR spectra gave no indication of homolysis. - Key words: Phosphorothioates, Raman Spectra, Infrared Spectra, Thionophosphorus, NMR Spectra, Thiophosphoramides
- Swinson, Joel,Field Lamar,Heimer, Norman E.,Michalska, Danuta,Muccio, Donald D.,et al.
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p. 159 - 172
(2007/10/02)
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