13455-01-1Relevant articles and documents
Unexpected Reactivity of Red Phosphorus in Ionic Liquids
Groh, Matthias F.,Paasch, Silvia,Weiz, Alexander,Ruck, Michael,Brunner, Eike
, p. 3991 - 3994 (2015)
Red phosphorus is far less reactive than the white allotrope. On the other hand, it is easier to handle and not as toxic as white phosphorus. In the Lewis-acidic ionic liquid (IL) [BMIm]Cl·2AlCl3 ([BMIm] = 1-butyl-3-methylimidazolium), red phosphorus and elemental iodine form several iodides at moderate temperature. 31P liquid- and solid-state NMR spectroscopy was used to rationalize the reaction at various temperatures and ratios of the starting materials. Monitoring of the reaction revealed nanoscale red-phosphorus particles. In addition to this top-down formation, phosphorus nanoparticles were also obtained in a bottom-up synthesis by dissociation of P2I4 in the IL. Depending on the ratio of red phosphorus and iodine, as well as the reaction temperature, P2I4, PI3, or P2I5+ dominate. Red phosphorus readily reacts with iodine in a Lewis-acidic ionic liquid at moderate temperature. Besides iodides, phosphorus nanoparticles are formed. The latter are also obtained in a bottom-up process starting from P2I4. In situ liquid- and solid-state NMR spectroscopy reveals details of the reactions.
Preparation of stable AsBr4+ and I2As-PI 3+ salts. Why didn't we succeed to prepare AsI 4+ and As2X5+? A combined experimental and theoretical study
Gonsior, Marcin,Krossing, Ingo
, p. 1203 - 1213 (2005)
In analogy to our successful PX2+ insertion reactions, an AsX2+ insertion route was explored to obtain new arsenic halogen cations. Two new salts were prepared: AsBr4+[Al(OR)4]-, starting from AsBr3, Br2 and Ag[Al(OR)4], and I 2As-PI3+[Al(OR)]4 from AsI 3, PI3 and Ag[Al(OR)4] (R = C(CF 3)3). The first cation is formally a product of an AsBr2+ insertion into the Br2 molecule and the latter clearly a PI2+ insertion into the As-I bond of the AsI3 molecule. Both compounds were characterized by IR and NMR spectroscopy, the first also by its X-ray structure. Reactions of Ag[Al(OR)4] with AsI3 do not lead to ionization and Agi formation but rather lead to a marginally stable Ag(AsI3)2+[Al(OR)]4 salt. Despite many attempts we failed to prepare other PX-cation analogues such as AsI 4+, As2X5+ and P 4AsX2+ (X = Br, I). To explain these negative results the thermodynamics of the formation of EX2+, EX4+ and E2X5+ (E = As, P; X = Br, I) was carefully analyzed with MP2/TZVPP calculations and inclusion of entropy and solvation effects. We show that As2Br5 + is in very rapid equilibrium with AsBr2+ and AsBr3 (ΔG°(CH2Cl2) = +30 kJ mol -1). The extremely reactive AsBr2+ cation available in the equilibrium accounts for the observed decomposition of the [Al(OR)4]- anion. By contrast, the stability of AsI 3 against Ag[Al(OR)4] appears to be kinetic and, if prepared by a suitable route, As2I5+ would be expected to have a stability intermediate between the known P2I 5+ and P2Br5+. The Royal Society of Chemistry 2005.
Characterisation of the tetrahalophosphonium cations PBrnI4 - n+ (0 ≤ n ≤ 4) by 31P MAS NMR, IR and Raman spectroscopy and the crystal structures of PI4+AlCl4-, PI4+AlBr4- and PI4+GaI4-
Aubauer,Kaupp,Klapoetke,Noeth,Piotrowski,Schnick,Senker,Suter
, p. 1880 - 1889 (2001)
The novel tetrahalophosphonium salts PBr4+AsF6-, PI4+AlCl4- and PI4+EBr4- (E = Al, Ga) have been synthesised. A variety of solid complexes containing PBr4+ (e.g. PBr4+AsF6-, PBr4+AlBr4- PBr4+GaBr4-), PI4+ (e.g. PI4+AlCl4-, PI4+AlBr4-, PI4+GaBr4-) or the mixed species PBrnI4 - n+ (0 ≤ n ≤ 4, containing AlBr4-, GaBr4-, AsF6- or SbF6-) have been studied by solid-state 31P MAS NMR and vibrational spectroscopy. The influence of the counter-ion on the chemical shift and the vibrational frequencies are discussed. The crystal structures of PI4+AlCl4-, PI4+AlBr4- and PI4+GaI4- are reported. Evidence for the existence of the hitherto unknown mixed bromoiodophosphonium cations PBr3I+, PBr2I2+ and PBrI3+ has been confirmed by spin-orbit corrected density functional calculations of isotropic 31P chemical shifts for PBrnI4 - n+.
Reactions of P4 and I2 with Ag[Al(OC(CF3)3)4]: From elusive polyphosphorus cations to subvalent P3I6+ and phosphorus rich P5I2+
Krossing, Ingo
, p. 500 - 512 (2007/10/03)
Reactions of X2 (X = Br, I), P4 and Ag(CH2Cl2)[Al(OR)4] [R = C(CF3)3] in suitable ratios to prepare naked polyphosphorus cations were carried out and led to products which sugges
