2015-56-7Relevant articles and documents
Ultrafast spectroscopy and computational study of the photochemistry of diphenylphosphoryl azide: Direct spectroscopic observation of a singlet phosphorylnitrene
Vyas, Shubham,Muthukrishnan, Sivaramakrishnan,Kubicki, Jacek,McCulla, Ryan D.,Burdzinski, Gotard,Sliwa, Michel,Platz, Matthew S.,Hadad, Christopher M.
, p. 16796 - 16804 (2010)
The photochemistry of diphenylphosphoryl azide was studied by femtosecond transient absorption spectroscopy, by chemical analysis of light-induced reaction products, and by RI-CC2/TZVP and TD-B3LYP/TZVP computational methods. Theoretical methods predicted two possible mechanisms for singlet diphenylphosphorylnitrene formation from the photoexcited phosphoryl azide. (i) Energy transfer from the (π,π*) singlet excited state, localized on a phenyl ring, to the azide moiety, thereby leading to the formation of the singlet excited azide, which subsequently loses molecular nitrogen to form the singlet diphenylphosphorylnitrene. (ii) Direct irradiation of the azide moiety to form an excited singlet state of the azide, which in turn loses molecular nitrogen to form the singlet diphenylphosphorylnitrene. Two transient species were observed upon ultrafast photolysis (260 nm) of diphenylphosphoryl azide. The first transient absorption, centered at 430 nm (lifetime (τ) ～ 28 ps), was assigned to a (π,π*) singlet S1 excited state localized on a phenyl ring, and the second transient observed at 525 nm (τ ～ 480 ps) was assigned to singlet diphenylphosphorylnitrene. Experimental and computational results obtained from the study of diphenyl phosphoramidate, along with the results obtained with diphenylphosphoryl azide, supported the mechanism of energy transfer from the singlet excited phenyl ring to the azide moiety, followed by nitrogen extrusion to form the singlet phosphorylnitrene. Ultrafast time-resolved studies performed on diphenylphosphoryl azide with the singlet nitrene quencher, tris(trimethylsilyl)silane, confirmed the spectroscopic assignment of singlet diphenylphosphorylnitrene to the 525 nm absorption band.
Characterizing the thermal degradation mechanism of two bisphosphoramidates by TGA, DSC, mass spectrometry and first-principle theoretical protocols
Castrejón-Flores, José Luis,Flores-Martinez, Yazmin M.,Franco-Pérez, Marco,García-Ventura, María Isabel,Reyna-Luna, Julieta,Zamudio-Medina, Angel
, (2020/07/16)
The present investigation describes a combined experimental-theoretical strategy to assess the thermal resistance features of two symmetric bisphosphoramidates, tetraphenyl ethane-1,2-diylbis (phosphoramidate) 1 and tetraphenyl propane-1,3-diylbis (phosphoramidate) 5. Therefore, their structural reluctance to thermal decomposition through differential scan calorimetric (DSC) and thermogravimetric (TGA) experiments was evaluated. Then, their molecular degradation path was followed by analysing recorded data from mass spectrometry measurements performed at different temperature conditions. Their corresponding thermal degradation mechanism was then established by searching plausible transition states interconnecting the intermediaries found in our mass spectrometry records using a quantum theoretical protocol based on Coupled-Cluster calculations. Through this strategy, key intermediaries of the two bisphosphoramidates studied during their molecular degradation mechanism were identified, although compound 5 displayed the highest resistance to heat decomposition.
An efficient chemoselective production of amines from azides using AlCl3/NaBH4
Raja Ram,Purushothama Chary,Salahuddin,Iyengar
, p. 935 - 937 (2007/10/03)
A practical reagent system AlCl3/NaBH4 is used for the preparation of amines from azides under mild reaction condition, in excellent yields.
New mixed-donor unsymmetrical P-N-P ligands and their palladium(II) complexes
Necas,Foreman,Marek,Woollins,Novosad
, p. 1256 - 1263 (2007/10/03)
Unsymmetrical bidentate ligands R2P(E)-N(H)-P(E′)R′2 [R, R′ = Ph, OPh, iPr; E, E′ = O, S, Se] have been synthesised using the condensation reaction of an amino compound, R2P(E)NH2 [R = PhO, Ph; E = O, S, Se], with a phosphorus electrophile, R′2P(E′)C1 [R′ = iPr, Ph, OPh; E′ = O, S, Se]. Deprotonated ligands (with KOtBu) can be treated with Pd(OAc)2 to give [Ph2P(S)-N-P(O)(OPh)2]2Pd, [iPr2P(S)-N-P(O)(OPh)2]2Pd and [Ph2P(S)-N-P(S)(OPh)2]2Pd, which show either four-membered or six-membered chelate rings. The new compounds were studied spectroscopically (NMR, IR and Raman) and by X-ray crystallography.
A novel and efficient production of amines from azides using LiCl/NaBH4
Raja Ram,Purushothama Chary,Iyengar
, p. 4495 - 4500 (2007/10/03)
A practical and efficient reagent system LiCl/NaBH4 is used for the production of amines from azides is described.
A novel, chemoselective and efficient production of amines from azides using ZrCl4/NaBH4
Purushothama Chary,Raja Ram,Salahuddin,Iyengar
, p. 3559 - 3563 (2007/10/03)
A practical and cheaper reagent system ZrCl4/NaBH4 is used for the production of amines from azides is described.
Synthese et reactions de N-acylphosphoramides apparentes aux ceto-4 diaza-1,3 phospholanes-2
Mulliez, Michel
, p. 1211 - 1218 (2007/10/02)
A new, general method, more efficient than previous ones, for the synthesis of N-acylphosphoramides 3, by reacting the silylated primary phosphoramides 2 with carboxylic chlorides is described (Figure 2).It is applied to the synthesis of precursors B and C and acyclic analogs D and E of the 4-keto 1,3-diaza, 2-phospholanes A (Figure 1). 3c (B) and 3a (C) lead to 15 (A) (Figure 5) and 17 (Figure 6) (A) in presence of sodium hydride, and hydrogen with palladium on charcoal as catalyst, respectively.Phosphorane 19 is formed from 3a and triphenylphosphine (Figure 6).D and E are not phosphorylating reagents but acylating ones.
Reagents and synthetic methods. 20: Reaction of diphenylphosphorophthalimide with alkyl- or arylamines. Synthesis of N-substituted phthalimides
Andres, Jose Angel,Palomo, Claudio
, p. 369 - 371 (2007/10/02)
Some N-substituted phthalimides are obtained from alkyl or arylamines by means of diphenyl phosphorophthalimide.A possible mechanism for that conversion is briefly discussed.
