2283-11-6Relevant articles and documents
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Fowell,Mortimer
, p. 2913 (1959)
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Insignificance of P-H...P hydrogen bonding: Structural chemistry of neutral and protonated 1,8-di(phosphinyl)naphthalene
Reiter, Stephan A.,Nogai, Stefan D.,Karaghiosoff, Konstantin,Schmidbaur, Hubert
, p. 15833 - 15843 (2004)
While there is extensive information on 1,8-di(amino)naphthalene (i.e., the parent compound of the proton sponge series), the corresponding phosphorus compound has not been described. A high-yield synthesis of 1,8-di(phosphinyl)naphthalene (9) and the 1-naphthylphosphine reference compound (4) is now reported. Thermal decomposition of 9 leads to intramolecular dehydrogenative P-P coupling to afford 1,2-dihydro-1,2-diphosphaacenaphthene (10). Protonation of 9 and 4 with CF3SO3H gives quantitative yields of the monophosphonium salts 11 and 5, respectively. With excess acid and traces of moisture, the hydronium salt [C10H 6(PH2)(PH3)]+[H3O] +2[CF3SO3]- (13) is obtained. The structures of 9, 11, and 13 have been determined. Molecules of 9 have a planar naphthalene skeleton, C10H6P2, with the two -PH2 groups in a transoid conformation. The molecules form loose dimers in the crystal, the individual chiral enantiomers of which are related by a center of inversion. In contrast to the situation for the amino analogue, and despite the proximity of the two -PH2 functions, there is no intra- or intermolecular hydrogen bonding. Solutions of 9 (in CD2Cl 2) show equivalent P-bound hydrogen atoms due to conformational fluctionality. By analysis of the ABCD2XX′D′ 2C′B′A′ spin system, it was shown that, in 9, there are strong through-space pericouplings [nJ(PXP X′) = 221.6 Hz, nJ(PXH D′) = 31.7 Hz, nJ(HDHD′) = 3.9 Hz]. In the cations of 11, the C10H6P2 skeleton is also planar (by Cs symmetry), with the -PH2 and -PH3+ groups in a conformation which rules out any P-H...P hydrogen bonding. The hydronium cation and the two triflate anions in 13 are associated into an anionic network through extensive hydrogen bonding surrounding stacks of the phosphonium cations. In solution, the cations of 11 and 13 show separate 31P resonances for the two phosphorus atoms with fully resolved 1J(PH) couplings, which indicate that there is no intra- or intercationic proton exchange. By contrast, the NMR spectra of solutions of [C10H6(NH2)(NH3)] +X- salts show proton scrambling equilibrating all five N-bound hydrogen atoms, and in the crystal, the conformations of the cations feature intramolecular N-H...N hydrogen bonding.
Macrocyclic systems on the basis of phosphorus acids and 2,7-dihydroxynaphthalene
Rasadkina,Slitikov,Evdokimenkova,Nifant'ev
, p. 1208 - 1212 (2003)
Syntheses of macrocyclic systems containing three 2,7-dihydroxynaphthalene residues and three residues of thiophosphoric and phosphorous amides in various ratios are developed. Chemical properties of the obtained compounds are studied.
EPR and ENDOR spectroscopic study of the reactions of aromatic azides with gallium trichloride
Bencivenni, Giorgio,Cesari, Riccardo,Nanni, Daniele,El Mkami, Hassane,Walton, John C.
supporting information; experimental part, p. 5097 - 5104 (2010/12/24)
The reactions of gallium trichloride with phenyl and deuterio-phenyl azides, as well as with 4-methoxyphenyl azide and deuterium isotopomers, were examined by product analysis, CW EPR spectroscopy and pulsed ENDOR spectroscopy. The products included the corresponding anilines together with 4-aminodiphenylamine type dimers, and polyanilines. Complex CW EPR spectra of the radical cations of the dimers [ArNHC6H4NH 2]+ and trimers [ArNHC6H4NHC 6H4NH2]+ were obtained. These EPR spectra were analysed with the help of data from the deuterium-substituted analogues as well as the pulse Davies ENDOR spectra. DFT computations of the radical cations provided corroborating evidence and suggested the unpaired electrons were accommodated in extensive π-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposed.
Synthesis of N6,N6-dialkyladenine nucleosides using hexaalkylphosphorus triamides produced in situ
Lakshman, Mahesh K.,Choudhury, Asad,Bae, Suyeal,Rochttis, Eliezer,Pradhan, Padmanava,Kumar, Amit
experimental part, p. 152 - 159 (2009/07/05)
Reactions between secondary amines and phosphorus trichloride (PCl 3) leads to the formation of the corresponding tris(dialkylamino) phosphanes or hexaalkylphosphorus triamides [HAPTs: (R2N) 3P]. Treatment of silyl-protected 2′-deoxyinosine and acetyl-protected inosine with the HAPTs produced in situ, together with iodine (I2), leads to the formation of N6,N6- dialkyladenosine and -2′-deoxyadenosine. In some cases the stoichiometry of the amine is important, as is the use of a tertiary amine base. The effect of amine stoichiometry on the reaction between HAPT and I2 has been studied by 31P{1H} NMR spectroscopy. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.