Free Difluorobis(pentafluoroethyl)phosphoranide Ion and Its Ligand Properties

Abstract

In this contribution, we report on the “free” [P­(C2F5)2F2]− ion and its ligand properties in transition metal complex chemistry. For this purpose, Ag­[P­(C2F5)2F2] was treated with [{(Et2N)3PN}3PNHC­(CH3)3]Cl ([EtP4H]­Cl) to yield [EtP4H]­[P­(C2F5)2F2], featuring a weakly coordinating phosphazenium cation. Due to the weak interaction between the cation and anion, the [P­(C2F5)2F2]− ion meets the so-called pseudo-gas-phase conditions. To determine the Tolman electronic parameter, [EtP4H]­[Ni­(CO)3{P­(C2F5)2F2}] was prepared from [EtP4H]­[P­(C2F5)2F2] and [Ni­(CO)4], facilitating the classification of the P­(C2F5)2F2 moiety as a moderately π-acidic ligand. By treatment of [EtP4H]­[P­(C2F5)2F2] with [AuCl­(tht)], the neutral tetrahydrothiophene ligand was substituted by the phosphoranide ion, yielding [EtP4H]­[AuCl­{P­(C2F5)2F2}]. When Ag­[P­(C2F5)2F2] was treated with [AuCl­(tht)], on the other hand, the chloride was substituted. Transmetalation reactions of this type proved to be an efficient transfer method of the P­(C2F5)2F2 moiety, as further demonstrated by the reactions of Ag­[P­(C2F5)2F2] with [FeCl­(CO)2Cp], [FeCl­(CO)2Cp*], and [PdCl2(NCMe)2]. Surprisingly, P­(C2F5)2F demonstrated fluorinating abilities toward [FeCl­(CO)2Cp], [FeCl­(CO)2Cp*], [AuCl­(tht)], and [PdCl2(NCMe)2]. Apparently, fluorido transition metal complexes were generated in situ under the formation of P­(C2F5)2Cl. The fluorido iron and palladium complexes transfer their fluoride ions onto P­(C2F5)2F, yielding the respective phosphoranido complexes, featuring the P­(C2F5)2F2 moiety.

In situ formation of Ni(CO)4 contaminant during IR analyses using a metal-containing reaction cell

“…The Mond process is yet only used when high purity nickel is sought, because of the acute toxicity 4,5 of this compound. In spite of its toxicity, Ni(CO) 4 is routinely used in laboratories to prepare organometallic complexes 6 and thin films. 7 The description of the Mond process emphasizes that Ni(CO) 4 may form whenever Ni-based catalysts are reduced and exposed to CO at temperatures below 200 °C.…”

“…The Mond process is yet only used when high purity nickel is sought, because of the acute toxicity 4,5 of this compound. In spite of its toxicity, Ni(CO) 4 is routinely used in laboratories to prepare organometallic complexes 6 and thin films. 7…”

Triorganylphosphoranides: Realization of an Unusual Structural Motif Utilizing Electron Withdrawing Pentafluoroethyl Groups

“…Unfortunately, 19 F and 31 P NMR spectroscopic measurements of the product revealed, that 6 was not obtained in pure form, but as a mixture with the respective [P(C 2 F 5 ) 2 F 2 ] À [16,18] salt. The phosphorus atom of 6 gives rise to a broad doublet at À 69 ppm with a 1 J(F,P) coupling constant of 400 Hz in the 31 P NMR spectrum.…”

“…[15,16] Due to its high fluoride ion affinity (FIA) of 289 kJ/mol, we chose fluorobis(pentafluoroethyl)phosphane, P(C 2 F 5 ) 2 F, and treated it with different fluoride sources, furnishing [P(C 2 F 5 ) 2 F 2 ] À salts. [16,17,18] We would now like to extend that research on phosphoranides derived from P(C 2 F 5 ) 3 (FIA = 259 kJ/mol) [16] and P(C 2 F 5 ) 2 (CN) (FIA = 282 kJ/mol, see supporting information) to expand the scope of phosphoranides featuring three phosphorus carbon bonds.…”

“…Since pentafluoroethylphosphanes display higher fluoride ion affinities (FIAs) and are safer to handle than respective trifluoromethyl derivatives, we recently focused our research on the synthesis and reactivity of pentafluoroethylphosphoranides [15,16] . Due to its high fluoride ion affinity (FIA) of 289 kJ/mol, we chose fluorobis(pentafluoroethyl)phosphane, P(C 2 F 5 ) 2 F, and treated it with different fluoride sources, furnishing [P(C 2 F 5 ) 2 F 2 ] − salts [16,17,18] . We would now like to extend that research on phosphoranides derived from P(C 2 F 5 ) 3 (FIA=259 kJ/mol) [16] and P(C 2 F 5 ) 2 (CN) (FIA=282 kJ/mol, see supporting information) to expand the scope of phosphoranides featuring three phosphorus carbon bonds.…”