The reactivity of an anionic phosphanylphosphinidene complex of tungsten(VI), [(2,6-i-Pr2C6H3N)2(Cl)W(η(2)-t-Bu2P═P)]Li·3DME toward PMe3, halogenophosphines, and iodine was investigated. Reaction of the starting complex with Me3P led to formation of a new neutral phosphanylphosphinidene complex, [(2,6-i-Pr2C6H3N)2(Me3P)W(η(2)-t-Bu2P═P)]. Reactions with halogenophosphines yielded new catena-phosphorus complexes. From reaction with Ph2PCl and Ph2PBr, a complex with an anionic triphosphorus ligand t-Bu2P-P((-))-PPh2 was isolated. The main product of reaction with PhPCl2 was a tungsten(VI) complex with a pentaphosphorus ligand, t-Bu2P-P((-))-P(Ph)-P((-))-P-t-Bu2. Iodine reacted with the starting complex as an electrophile under splitting of the P-P bond in the t-Bu2P═P unit to yield [(1,2-η-t-Bu2P-P-P-t-Bu2)W(2,6-i-Pr2C6H3N)2Cl], t-Bu2PI, and phosphorus polymers. The molecular structures of the isolated products in the solid state and in solution were established by single crystal X-ray diffraction and NMR spectroscopy.

We report the synthesis of the first series of terminal phosphido iron complexes supported by a -diketiminato ligand (Dippnacnac) and their catalytic activity in dehydrocoupling of secondary phosphines. Anionic and neutral mono-or diphosphido complexes were obtained from the reaction of [(Dippnacnac)FeCl 2 Li(dme) 2 ] with the R 2 PLi (R = iPr, tBu, Cy, Ph) phosphides by tuning the stoichiometric ratio, polarity of the solvent, and the bulkiness of the substituents at the P-atom. The structures of the synthesized compounds were determined by single-crystal X-ray diffraction, which revealed that the iron [a] Reports by Webster et al. [14,27,43,[98][99][100][101][102] on the use of an iron(II) -diketiminato pre-catalyst, [(Dippnacnac)Fe(CH 2 TMS)] for the hydrophosphination of unsaturated hydrocarbons and dehydrocoupling of primary and secondary phosphines postulated the formation of an intermediate terminal phosphido complex. In the case of hydrophosphination, the authors proposed that the active catalyst is a monomeric phosphido complex; however, the active species was isolated as a bridging complex, [(Dippnacnac)Fe(PRH(CH 2 ) 3 CH=CH 2 )] 2 . [27] Worth emphasizing is that this compound is not only the first -diketiminate iron complex bridged by phosphido groups, but also a perfect example highlighting the catalytic potential of lowcoordinate iron compounds. The hydrophosphination and dehydrocoupling processes are both ideally suited for the synthesis of novel P-containing compounds and their catalytic improvements will expand the access to functionalized phosphines, diphosphanes, and other P-containing derivatives.Recently, we have reported a new synthetic method to access iron(II) phosphanylphosphido complexes using as starting materials the -diketiminato complex [(Dippnacnac)FeCl 2 -Li(dme) 2 ] [103] and lithium salts of diphosphanes, R 2 P-P(SiMe 3 )Li (R = iPr, tBu). [104] Due to the propensity of the diphosphorus ligand to undergo P-P bond cleavage, these iron(II) phosphanylphosphido complexes have rather limited catalytic potential. Considering this limitation, we directed our attention to iron(II) complexes with phosphido R 2 P ligands. In this paper, we detail the syntheses, structures, and spectroscopic characterization of the first series of terminal phosphido Fe II complexes stabilized by -diketiminates. We also discuss their thermal stability and catalytic activity in promoting the dehydrocoupling of secondary phosphines. Reaction of [(Dippnacnac)FeCl 2 ] with Ph 2 PLi:To the suspension of [(Dippnacnac)FeCl 2 ] (0.272 g, 0.5 mmol) in 2.5 mL of solvent (tolu-Eur.

This work describes a series of iron(II) phosphanylphosphido complexes. These compounds were obtained by reacting lithiated diphosphanes RPP(SiMe)Li (R = t-Bu, i-Pr) with an iron(II) β-diketiminate complex, [LFe(μ-Cl)Li(DME)] (1), where DME = 1,2-dimethoxyethane and L = Dippnacnac (β-diketiminate). While the reaction of 1 with t-BuPP(SiMe)Li yields [LFe(η-MeSiPP-t-Bu)] (2), that of 1 with equimolar amounts of i-PrPP(SiMe)Li, in DME, leads to [LFe(η-i-PrPPSiMe)] (3). In contrast, the reaction of 1 with (i-PrN)PP(SiMe)Li provides not an iron-containing complex but 1-[(diisopropylamino)phosphine]-2,4-bis(diisopropylamino)-3-(trimethylsilyl)tetraphosphetane (4). The structures of 2-4 were determined using diffractometry. Thus, 2 exhibits a three-coordinate iron site and 3 a four-coordinate iron site. The increase in the coordination number is induced by the change from an anticlinal to a synclinal conformation of the phoshpanylphosphido ligands. The electronic structures of 2 and 3 were assessed through a combined field-dependent Fe Mössbauer and high-frequency and -field electron paramagnetic resonance spectroscopic investigation in conjunction with analysis of their magnetic susceptibility and magnetization data. These studies revealed two high-spin iron(II) sites with S = 2 ground states that have different properties. While 2 exhibits a zero-field splitting described by a positive D parameter (D = +17.4 cm; E/D = 0.11) for 3, this parameter is negative [D = -25(5) cm; E/D = 0.15(5)]. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations provide insights into the origin of these differences and allow us to rationalize the fine and hyperfine structure parameters of 2 and 3. Thus, for 2, the spin-orbit coupling mixes a z-type ground state with two low-lying {xz/yz} orbital states. These interactions lead to an easy plane of magnetization, which is essentially parallel to the plane defined by the N-Fe-N atoms. For 3, we find a yz-type ground state that is strongly mixed with a low-lying z-type orbital state. In this case, the spin-orbit interaction leads to a partial unquenching of the orbital momentum along the x axis, that is, to an easy axis of magnetization oriented roughly along the Fe-P bond of the phosphido moiety.

We report the first series of homoleptic phosphido iron complexes synthesized by treating either the β-diketiminato complex [(Dippnacnac)FeCl₂Li(dme)₂] (Dippnacnac = HC[(CMe)N(C₆H₃‐2,6‐iPr₂)]₂) or [FeBr₂(thf)₂] with an excess of phosphides R₂PLi (R...