Experimental and theoretical investigation of the reactivity of [(BDI*)Ti(Cl){η2-P(SiMe3)-PiPr2}] towards selected ketones

Phosphanylphosphaalkenes as precursors for metallaphosphaalkene complexes

We synthesized phosphanylphosphaalkenes (biph)2CP-P(tBu)2 (2), Ph2CP-P(NEt2)2 (3), and (biph)2CP-P(NEt2)2 (4). The diaminophosphanyl derivatives reversibly dimerize head-to-head and react with a ruthenium complex, leading to P-P bond activation and the formation of a bridging phospaalkene complex under mild conditions.

Rhodium(I) Complexes with a η1-Fluorenyl-P-phosphanylphosphorane Ligand

The first example of a P-phosphanylphosphorane, Flu═PCy2-PCy2 (L2; Flu = 9-fluorenyl), has been easily prepared by P-phosphination of lithiated 9-dicyclohexylphosphinofluorene (FluPCy2, L0) with chlorodicyclohexylphosphane. L2 constitutes a new type of P(III)-P(V) organophosphorus compound, a σ3λ3-σ4λ5 species that is stable under an inert atmosphere in the solid state. The reaction of L2 with [Rh(diene)2]BR4 causes metalation of the benzylic carbon (C9) of fluorene, giving κ2-C,P complexes in which fluorene is coordinated in the η1 form. A complex with the weakly coordinating BArF anion has been isolated and fully characterized, including its crystal structure obtained by X-ray diffraction.

Activation of the C[double bond, length as m-dash]P bond in phosphanylphosphaalkenes (C[double bond, length as m-dash]P-P bond system) in the reaction with nucleophilic reagents: MeLi, nBuLi and tBuLi

Three reactions of phosphanylphosphaalkene (1) with nucleophiles were performed to activate the diphosphorus monomer. We observed similar results in the reactions with MeLi and nBuLi, in which the P-P bond is cleavaged and triphosphorus systems [P(Me)₂-CH(biph)-CH(biph)-P-(PtBu₂)]^- (1a'') and [P(nBu)₂-CH(biph)-CH(biph)-P-(PtBu₂)]^- (1b''), respectively, are formed depending on the nucleophilic reagent (biph = biphenyl). In the case of tBuLi, the P-P bond remains intact; on the phosphorus atom, only one -tBu group is substituted, and as a result, [(biph)(H)C-P(tBu)-PtBu₂]^- (1c) is generated as a stable carbanion. We additionally investigated the effect of substitution in the phenyl ring in the course of these reactions by involving two other phosphanylphosphaalkenes (3 and 4). All initial reactions were conducted in tetrahydrofuran (THF) solution at ambient temperature.

Two complementary approaches for the synthesis and isolation of stable phosphanylphosphaalkenes

A new series of compounds formed in a one-step  reaction (Phospha–Wittig  or phospha–Peterson), containing the CP–P moiety was synthesized and characterized. These species are stable under atmospheric conditions and are resistant to hydrolysis.