Synthesis of the Tetradentate Phosphine α,α,α‘,α‘-Tetrakis(diphenylphosphino)-p-xylene (dppx) and Crystal and Molecular Structure of (CO)₃Fe(dppx)Fe(CO)₃

Abstract

The tetradentate phosphine α,α,α‘,α‘-tetrakis(diphenylphosphino)-p-xylene (3, dppx) was prepared in two steps from α,α‘-bis(diphenylphosphino)-p-xylene (1) via the intermediate trisubstituted phosphine α,α,α‘-tris(diphenylphosphino)-p-xylene (2). The ligand, dppx, reacts with Fe2(CO)9 to afford a bridging bischelated complex Fe(CO)3(dppx)Fe(CO)3 (4), which was characterized by X-ray diffraction. Complex 4 crystallized in the monoclinic space group P21/n, a = 11.903(1) Å, b = 15.295(2) Å, c = 15.415(1) Å, β = 96.306(9)°, V = 2789.5(8)Å3, Z = 2, R = 0.072, and R w = 0.079.

Synthesis and transition metal chemistry of a bridging diphosphinite, 1,4 bis(diphenylphosphinoxy)benzene

“…Bis ( (17). Selected bond angles ( ): S1eP1eO1, 115.89(4); S1eP1eC4, 114.76(5); S1eP1eC10, 114.82(5); O1eP1eC4, 103.28(6); O1eP1eC10, 99.26(6); C4eP1eC10, 107.08 (7).…”

Synthesis, Characterization, and Catalytic Studies of Dinuclear d8 Metal–Phosphazane Complexes

“…Figure illustrates a substantial cost difference between the synthesis of a simple bis-P–N–P ( 1 ) versus its bis-P–C–P counterpart. Summing the reagent costs associated with treating α,α,α′,α′-tetrabromo- p -xylene with lithium diphenylphosphide reveals an ∼48-fold greater expense relative to synthesis of 1 reported herein …”

“…59 ∼48-fold greater expense relative to synthesis of 1 reported herein. 60 The central nitrogen atom of a phosphazane ligand typically deviates only slightly from an idealized sp 2 geometry. Caution is necessary when strong nucleophilic reagents (i.e., strong bases and organometallic reagents) and/or electron-withdrawing Rgroups, especially those on the nitrogen atom, are used.…”

“…Whereas the chemistry of bidentate P–C–P ligands has been well-studied by many groups including those of Shaw, − Puddephatt, − Kubiak, − and White, − phosphazane ligands have received far less attention. From a synthetic standpoint, phosphazanes offer a higher degree of tunability owing to the wide availability of primary amines that are used in their formation.…”

Geminally Substituted Tris(acenaphthyl) and Bis(acenaphthyl) Arsines, Stibines, and Bismuthine: A Structural and Nuclear Magnetic Resonance Investigation

“…An example of this coordinative variety includes the bimetallic iron­(II) complex F in which one tetrakis­(phosphine) ligand D is coordinating in a bidentate mode, and the other in a tridentate mode to one metal atom and monodentate to the other . More rigid tetradentate phosphines also form bimetallic bidentate systems such as complex G , which was obtained from the reaction of tetrakis­(diphenylphosphino)- p -xylene with Fe 2 (CO) 9 …”