Direct access to [(Mes*P)2As]−, a 1,3-diphosphaarsa-2-allyl anion, isoelectronic with the allyl anion (Mes* = 2,4,6-tBu3C6H2)

Abstract

The reaction of As(NMe2)3 with Mes*PHLi provides a direct source of the 1,3-diphosphaarsa-2-allyl anion, [(Mes*P)2As](-) (isoelectronic with the allyl anion). The equilibrium between the E,E and E,Z isomers of this anion depends on the extent of Li(+) ion-pairing.

Synthesis of a Molecule with Four Different Adjacent Pnictogens

“…However,d eprotonation of Mes*N(H)AsPMes* with nBuLia tÀ808Ca fforded ad ark red solution in variouss olvents, for example, Et 2 O, THF,E t 2 O/ toluene mixtures or 12-crown-4 in toluene. In agreement with previousr eports on NPPa nd PAsP anions, [16,18] these species are highly sensitive and tend to decompose in solution.T his behavior was confirmed for 3 as decomposition already began at À308C, resulting in the formationo fablack precipitate and an auseous odor.F or solutionst hat should contain the NAsP anion of 3,n o 31 PNMR resonance could be detected at low and at ambient temperature. Thus, the deprotonation was henceforth carriedo ut at low temperatures and kept at À808C until being quenched with solutionso fs toichiometrica mounts of SbCl 3 (assuming quantitative deprotonation).…”

“…[11] The heavierc ongeners featuring Pa toms with bulky substituents, [R-PPP-R] À and [R-PAsP-R] À ,w erei nvestigated by the groupso fL erner, [12] Jutzi, [13] Scheer, [14,15] and Wright. [16] Related cationic species of the type [As(P(NMe 2 ) 3 ) 2 ] + were studied by Driesse tal. [17] Au nique example of an asymmetric group 15 allyl analogue,[ R-NPP-R] À ,w as investigated by Niecke et al [18] The synthesis of the Nieckeg roup startedf rom imino-chlorophosphane, Mes*NPCl, which was treated with Mes*P(H)SiMe 3 , affording Mes*N(H)PPMes*.…”

An Acyclic Arsenium Cation Stabilised by a Single P–As π‐Interaction and a Cyclic Diphosphinophosphonium Salt

“…[17] TheP -As-P angles in 2 1 maj and 2 2 maj are 105.45(3) and 109.95(4)8 8.O verall, the structures of the cations 2 1 maj and 2 2 maj are remarkably similar to that of the isoelectronic diphosphagermylene VI [sum of angles at P = 358.35 and 311.538 8,P-Ge-P angle 107.4(4)8 8]. [17] TheP -As-P angles in 2 1 maj and 2 2 maj are 105.45(3) and 109.95(4)8 8.O verall, the structures of the cations 2 1 maj and 2 2 maj are remarkably similar to that of the isoelectronic diphosphagermylene VI [sum of angles at P = 358.35 and 311.538 8,P-Ge-P angle 107.4(4)8 8].…”

“…[As-P 2.176(1) and 2.170(1) ;T MEDA = N,N,N',N'-tetramethylethylenediamine]. [17] TheP -As-P angles in 2 1 maj and 2 2 maj are 105.45(3) and 109.95(4)8 8.O verall, the structures of the cations 2 1 maj and 2 2 maj are remarkably similar to that of the isoelectronic diphosphagermylene VI [sum of angles at P = 358.35 and 311.538 8,P-Ge-P angle 107.4(4)8 8]. [12] Them inor disorder components of the two independent cations (2 1 min and 2 2 min )have rather low occupancies (6 %and 8%,respectively), and so it is not appropriate to discuss their structures in detail;h owever,t he gross structural features of 2 1 min and 2 2 min are clear.…”

“…Forc omparison, the chemical shifts of the twocoordinate phosphorus centres in phosphaarsenes typically lie in the range 530-670 ppm; [15,16] the chemical shift observed for the planar phosphorus centre in 2a is closer to that observed for the 1,3-diphospha-2-arsaallyl anion in 3 (235.3 ppm for the E,E-isomer). [17] Thei dentity of the species responsible for peak B is less clear. We have previously observed similar variable-temperature NMR behaviour for the isoelectronic germylene VI:At À95 8 8C, the 31 P{ 1 H} NMR spectrum of VI consists of apair of broad signals at 98.5 and À82.0 ppm, corresponding to the planar and pyramidal phosphorus centres,respectively,along with two sharp singlets at 7.8 and À43.1 ppm, which were assigned to configurations containing two pyramidal phosphorus centres.…”