A Proton‐Triggered Cascade Reaction Involving a Heavy p‐Block Multiple Bond: Transformation of the Diphosphene C₅Me₅P=PC₅Me₅ into the Cationic Cage [C₁₀Me₁₀P₂H]⁺

Abstract

Protonation of one of the phosphorus centers of the diphosphene C5Me5P=PC5Me5 triggers a remarkable cascade reaction leading to the direct formation of a C10P2 cage. Calculations suggest that the key mechanistic feature is the proximity of a C=C π‐system to a developing positive charge on one of the phosphorus centers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Phosphines and related C–P bonded compounds

“…340 The formation of diphosphacyclobutenes in stereospecific [2 þ 2]-cycloaddition reactions of diphosphorus (P 2 ) with alkenes has been the subject of a theoretical study. 341 Studies of the reactivity of diphosphenes have included chalcogenation reactions of kinetically-stable diphosphenes with elemental sulfur, selenium and tellurium, leading to thia-, selena-and tellura-diphosphiranes, 342 the formation of a ferrocenyldiphosphine-platinum(0) complex, 343 the formation of a C 10 P 2 cationic cage system on protonation of the diphosphene C 5 Me 5 PQPC 5 Me 5 , 344 and the formation of a kineticallystabilised diphosphene anion-radical by the one-electron reduction of the diphosphene TbtPQPTbt (Tbt ¼ 2,4,6-tris[bis(trimethylsilyl)methyl] phenyl). 345 A successful protocol has been developed for the introduction of stable phosphaalkene units into oligoalkynes, leading to compounds of types (162) and (163), a new class of p-conjugated molecules.…”

Nitrogen, phosphorus, arsenic, antimony and bismuth

“…Protonation of Cp*PQPCp* has been shown to afford 45 which may then be deprotonated to give the crystallographically-characterised 46. 74 The protonation reaction was studied by DFT theory. The ability of Ti(Z 5 -C 5 H 5 ) 2 (TMSCRCTMS) to reductively couple dichlorophosphines PCl 2 R to give diphosphines (RClP-PClR) and diphosphenes (RPQPR) has been reported.…”

The azaphosphiridine to terminal phosphinidene complex rearrangement – looking for non-covalent interactions of a highly reactive species

“…In continuation of earlier efforts to develop azaphosphiridine complex chemistry, 13 we recently started to investigate the reaction of Li-Cl phosphinidenoid complexes towards aldimines. 14 As a main group element-bound Cp* group has offered interesting reactivity in the past, [14][15][16][17][18] we targeted a P-Cp* substituted aza-phosphiridine complex, unknown so far. When Li-Cl phosphinidenoid complex 2, 19 prepared from 1 and observed at 280.2 ppm ( 1 J WP = 76.5 Hz) in the 31 P{ 1 H} NMR spectrum, 20 was reacted in situ with aldimine 3, formation of the novel N,P,Ccage complex 5a occurred; the final product showed a 31 P{ 1 H} NMR resonance at À34.…”