Heterobimetallic Cooperation Mediates the Transformation of White Phosphorus into Zwitterioniccatena-Phosphonium(+)diphosphenide(−) Ligands

Iron-Gallium and Cobalt-Gallium Tetraphosphido Complexes

The synthesis and characterization of two heterobimetallic complexes [K([18]crown-6){(η4-C14H10)Fe(μ-η4:η2-P4)Ga(nacnac)}] (1) (C14H10 = anthracene) and [K(dme)2{(η4-C14H10)Co(μ-η4:η2-P4)Ga(nacnac)}] (2) with strongly reduced P4 units is reported. Compounds 1 and 2 are prepared by reaction of the gallium(III) complex [(nacnac)Ga(η2-P4)] (nacnac = CH[CMeN(2,6-iPr2C6H3)]2) with bis(anthracene)ferrate(1-) and -cobaltate(1-) salts. The molecular structures of 1 and 2 were determined by X-ray crystallography and feature a P4 chain which binds to the transition metal atom via all four P atoms and to the gallium atom via the terminal P atoms. Multinuclear NMR studies on 2 suggest that the molecular structure is preserved in solution.

Diphosphoniodiphosphene Formation by Transition Metal Insertion into a Triphosphenium Zwitterion

Treatment of two equivalents of the triphosphenium zwitterion L with sources of Ni⁰ and Pd⁰ form the mononuclear η² -diphosphoniodiphosphene complexes 1 and 2. The reaction between L and [FeCp(CO)₂ ]₂ results in the binuclear μ-η¹ :η¹ -diphosphoniodiphosphene iron complex 3, which features an alternative bonding motif of the diphosphoniodiphosphene unit. The formation of these species has been confirmed by spectroscopic methods and single-crystal X-ray diffraction analysis, and their electronic structures have been elucidated using computational methods.

Reaction of Pentelidene Complexes with Diazoalkanes: Stabilization of Parent 2,3-Dipnictabutadienes

The reaction of the phosphinidene complex [Cp*P{W(CO)₅ }₂ ] (1 a) with diphenyldiazomethane leads to [{W(CO)₅ }Cp*P=NN{W(CO)₅ }=CPh₂ ] (2). Compound 2 is a rare example of a phosphadiazadiene ligand (R-P=N-N=CR'R'') complex. At temperatures above 0 °C, 2 decomposes into the complex [{W(CO)₅ }PCp*{N(H)N=CPh₂ )₂ ] (3), among other species. The reaction of the pentelidene complexes [Cp*E{W(CO)₅ }₂ ] (E=P, As) with diazomethane (CH₂ NN) proceeds differently. For the arsinidene complex (1 b), only the arsaalkene complex 4 b [{W(CO)₅ }₂ {η^1:2 -(Cp*)As=CH₂ }] is formed. The reaction with the phosphinidene complex (1 a) results in three products, the two phosphaalkene complexes [{W(CO)₅ }₂ {η^1:2 -(R)P=CH₂ }] (4 a: R=Cp*, 5: R=H) and the triazaphosphole derivative [{W(CO)₅ }P(Cp*)-CH₂ -N{W(CO)₅ }=N-N(N=CH₂ )] (6 a). The phosphaalkene complex (4 a) and the arsaalkene complex (4 b) are not stable at room temperature and decompose to the complexes [{W(CO)₅ }₄ (CH₂ =E-E=CH₂ )] (7 a: E=P, 7 b: E=As), which are the first examples of complexes with parent 2,3-diphospha-1,3-butadiene and 2,3-diarsa-1,3-butadiene ligands.