Utilizing the Perfluoronaphthalene Radical Cation as a Selective Deelectronator to Access a Variety of Strongly Oxidizing Reactive Cations.

A selective deelectronation reagent with very high potential of +2.00 (solution) / +2.41 V (solid-state) vs. Fc+/0 and based on a room temperature stable perfluoronaphthalene (naphthaleneF) radical cation salt was developed and applied. The solid-state deelectronation of commercial naph-tha-leneF with [NO]+[F{Al(ORF)3}2]- generates [naphthaleneF]+∙[F{Al(ORF)3}2]- (ORF = OC(CF3)3) in gram scale. Thermo-chemical analysis unravels the solid-state de-electronation potential of the starting [NO]+-reagent to be +2.34 V vs. Fc+/0 with [F{Al(ORF)3}2]- counterion, but only +1.14 V vs. Fc+/0 with the small [SbF6]- ion. Selective reactions demonstrate the selectivity of [naphthaleneF]+∙ for deelectronation of a multitude of organ(ometall)ic molecules and elements in solution: providing the molecular struc-tures of the acene dications [tetracene]2+, [pentacene]2+ or spectroscopic evi-dence for the carbo-nyl complex of the ferrocene dication [Fc(CO)]2+, the [P9]+ cation from white phosphor-us, the solvent-free copper(I) salt starting from copper metal and the dicationic Fe(IV)-scorpionate complex [Fe(sc)2]2+.

Teaching old tricks to new dogs - rational synthesis of multi-decker complexes featuring cyclo-P5 decks.

A rational synthetic pathway towards a series of cyclo-P5-bearing multi-decker complexes was developed. The combination of [Cp*Fe(µ,η5 : 5-P5)] (A) with low-valent transition metal cations yields a series of triple-decker complexes [Cp*Fe(µ,η5 : 5-P5)MCp'''][WCA] (M = Cr - Ni; WCA = weakly coordinating anion, Cp''' = 1,2,4-tBu3C5H2). Utilizing the arene complexes [M(C6R6)2][WCA]n (M = Fe, Co) instead allowed the synthesis of the unprecedented cyclo-P5-containing quadruple-decker complexes [{Cp*Fe(µ,η5 : 5-P5)}2M][pf]n (M = Fe, Co).

Homoatomic cations: From [P5]+ to [P9].

Recent synthetic approaches to a series of [P9]X salts (X = [F{Al(ORF)3}2], [Al(ORF)4], and (RF = C(CF3)3); Ga2Cl7) overcome limitations in classical synthesis methods that proved unsuitable for phosphorus cations. These salts contain the homopolyatomic cation [P9]+ via (I) oxidation of P4 with NO[F{Al(ORF)3}2], (II) the arene-stabilized Co(I) sandwich complex [Co(arene)2][Al(ORF)4] [arene = ortho-difluorobenzene (o-DFB) and fluorobenzene (FB)], or (III) the reduction of [P5Cl2][Ga2Cl7] with Ga[Ga2Cl7] as Ga(I) source in the presence of P4. Quantum chemical CCSD(T) calculations suggest that [P9]+ formation from [Co(arene)2]+ occurs via the nido-type cluster [(o-DFB)CoP4]+, which resembles the isoelectronic, elusive [P5]+. Apparently, the nido-cation [P5]+ forms intermediately in all reactions, particularly during the Ga(I)-induced reduction of [P5Cl2]+ and the subsequent pick up of P4 to yield the final salt [P9][Ga2Cl7]. The solid-state structure of [P9][Ga2Cl7] reveals the anticipated D2d-symmetric Zintl-type cage for the [P9]+ cation. Our approaches show great potential to bring other [Pn]+ cations from the gas to the condensed phase.

Isolable Phosphaalkenes Bearing 2,4,6-Trimethoxyphenyl and 2,6-Bis(trifluoromethyl)phenyl as P-Substituents.

The multistep synthesis and characterization of new P═C analogues of olefins from readily available starting materials is reported. Specifically, the phosphaalkenes TMOP-P═CPh2 (1a: TMOP = 2,4,6-trimethoxyphenyl) and ArF-P═CPh2 [1b: ArF = 2,6-bis(trifluoromethyl)phenyl] have been prepared, isolated, and characterized. In addition, synthetically challenging intermediates, such as the corresponding pyrophoric primary phosphines and bis(trimethylsilyl)phosphines, have been isolated and characterized. The title compounds, TMOP-P═CPh2 (1a) and ArF-P═CPh2 (1b), along with TMOP-PH2 (3a) have been characterized by X-ray crystallography. Importantly, the successful synthesis and isolation of phosphaalkenes 1a and 1b provides a foundation for future investigations of their polymerization, by analogy to the known polymerization of Mes-P═CPh2.

First experimental evidence for the elusive tetrahedral cations [EP3]+ (E = S, Se, Te) in the condensed phase.

Condensed phase access to the unprecedented tetrahedral cations [EP3]+ (E = S, Se, Te) was achieved through the reaction of ECl3[WCA] with white phosphorus ([WCA]- = [Al(ORF)4]- and [F(Al(ORF)3)2]-; -RF = -C(CF3)3). Previously, [EP3]+ was only known from gas phase MS investigations. By contrast, the reaction of ECl3[A] with the known P3 3- synthon Na[Nb(ODipp)3(P3)] (enabling AsP3 synthesis), led to formation of P4. The cations [EP3]+ were characterized by multinuclear NMR spectroscopy in combination with high-level quantum chemical calculations. Their bonding situation is described with several approaches including Atoms in Molecules and Natural Bond Orbital analysis. The first series of well-soluble salts ECl3[WCA] was synthesized and fully characterized as starting materials for the studies on this elusive class of [EP3]+ cations. Yet, with high [ECl3]+ fluoride ion affinity values between 775 (S), 803 (Se) and 844 (Te) kJ mol-1, well exceeding typical phosphenium ions, these well-soluble ECl3[WCA] salts could be relevant in view of the renewed interest in strong (also cationic) Lewis acids.