'P' undressed: A stable phosphanylidene phosphorane with a sterically accessible (naked) two‐coordinate P is reported (see structure). Coordination to Pd0 reveals its phosphine donor/phosphinidene acceptor (R3P→PR′) nature by exposing its phosphinidene‐like reactivity.

The reactions of a peri-substitution stabilized phosphanylidene-phosphorane 1 with [AuCl(tht)] or [PtCl2(cod)] afford binuclear complexes [((1)(AuCl)2)2] 2 and [((1)(PtCl2))2] 3, in which four electrons of the ligand are used in bonding to two metal atoms in the bridging arrangement. Reactions of 1 with [Mo(CO)4(nbd)] or (RhCl2Cp*)2 afford mononuclear complexes [(1)2Mo(CO)4] 4 and [(1)RhCl2Cp*] 5, in which two electrons of the ligand are used to form terminal complexes. Formation of these complexes disrupts the negative hyperconjugation at the P-P bond to various extent, which is mirrored by variations in their P-P bond distances (2.179(4)-2.246(4) Å). The P-P bond is ruptured upon formation of the Pd diphosphene complex 6, which is likely to proceed through a phosphinidene intermediate. In air 1 is fully oxidized to phosphonic acid 7. Reactions of 1 with chalcogens under mild conditions generally afford mixtures of products, from which the trithionated 8, dithionated 9, diselenated 10 and monotellurated species 11 were isolated. The bonding in the chalcogeno derivatives is discussed using DFT (B3LYP) and natural bond orbital analysis, which indicates a contribution from a dative bonding in 8-10. The buttressing effect of the peri-backbone is shown to be an essential factor in the formation of the single push-double pull bis(borane) 13. This is demonstrated experimentally through a synthesis parallel to that used to make 13, but lacking the backbone, which leads to different products. The P-P bond distances in the reported products, as well as additional species, are correlated with Wiberg Bond Indices, showing very good agreement for a variety of bonding modes including the negative hyperconjugation.

The fundamental synthetic building blocks FcPH2 and FcPCl2 are obtained in high yield and excellent purities via the fully regiospecific electrophilic monofunctionalisation of ferrocene with P4S10, thus replacing inconvenient tBuLi based procedures.

Acyl oximes derived from a variety of indolylalkanones underwent a ring closure sequence during FVP to afford 9H-pyrido[2,3-b]indoles. Unlike UV light promoted reactions of oxime esters, the mechanism is almost certainly not mediated by iminyl radicals but probably involves tautomerism, elimination of acetic acid, and a final electrocyclic ring closure.