A PH-functionalized dicationic bis(imidazolio)diphosphine

Reaction of the iodide salt of a secondary imidazolio-iodophosphine [(L)PHI]I (L+ = 1,3-diarylimidazolium-yl) with an imidazolio-phosphide (L)PH in the presence of GaI3 afforded the isolable salt of a dicationic, bis(imidazolio)-substituted dihydro-diphosphine [(L)(2)P2H2][GaI4](2). Non-preparative formation of the cationic diphosphines was also observed upon spontaneous "dehalo-coupling" of [(L)PHI](+), or in reactions of [(L)PHI]I and (L)PH in the absence of GaI3. Further reaction of [(L)(2)P2H2](2+) with (L)PH produced an iodide salt of a known (bis)imidazolio-diphosphide monocation [(L)(2)P2H](+). The identity of cationic diphosphines and diphosphides was established by single-crystal X-ray diffraction studies. NMR spectroscopy revealed that dications [(L)(2)P2H2](2+) exist as a mixture of meso- and rac-diastereomers in solution. Computational studies confirmed the stereochemical assignment of the isomers observed, and gave insight into the bonding situation of the diphosphine dications.Peer reviewe

Preparation and Characterization of P(2)BCh Ring Systems (Ch=S, Se) and Their Reactivity with N-Heterocyclic Carbenes

Four-membered rings with a P2BCh core (Ch = S, Se) have been synthesized via reaction of phosphinidene chalcogenide (Ar*P=Ch) and phosphaborene (Mes*P=BNR2). The mechanistic pathways towards these rings are explained by detailed computational work that confirmed the preference for the formation of P–P, not P–B, bonded systems, which seems counterintuitive given that both phosphorus atoms contain bulky ligands. The reactivity of the newly synthesized heterocycles, as well as that of the known (RPCh)n rings (n = 2, 3), was probed by the addition of Nheterocyclic carbenes, which revealed that all investigated compounds can act as sources of low-coordinate phosphorus species.peerReviewe

Selective [3+1] Fragmentations of P4 by “P” Transfer from a Lewis Acid Stabilized [RP4]- Butterfly Anion

Two [3+1] fragmentations of the Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutanide Li[Mes*P4⋅ BPh3] (Mes*=2,4,6-tBu3C6H2) are reported. The reactions proceed by extrusion of a P1 fragment, induced by either an imidazolium salt or phenylisocyanate, with release of the transient triphosphirene Mes*P3, which was isolated as a dimer and trapped by 1,3-cyclohexadiene as a Diels–Alder adduct. DFT quantum chemical computations were used to delineate the reaction mechanisms. These unprecedented pathways grant access to both P1- and P3-containing organophosphorus compounds in two simple steps from white phosphorus