Synthesis of a functional C2-symmetrical bidentate diphenylphosphonite DIOP derivative and its conversion into the corresponding pi-acidic bis(pentafluorophenyl) and bis(p-tetrafluoropyridyl) compounds.
The reaction of a C2-symmetric diiodo compound, 1,4-dideoxy-1,4-diiodo-2,3,-O-isopropyliden-L-threitole, with [K([18]crown-6)]P(CN)2 led to the generation of a corresponding bidentate dicyanophosphorus derivative. The in situ reaction with excess methanol and phenol yielded the corresponding bidentate dimethyl- and diphenylphosphonites, respectively. The isolated liquids were characterized by multinuclear NMR spectroscopy, elemental analysis, and mass spectrometry. The bidentate diphenylphosphonite ligand (a diphenoxyphosphane derivative) represents one of the very few functional bidentate phosphane derivatives: a DIOP [(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(diphenylphosphane) modification, in which the phenyl groups at the phosphorus atoms are replaced by functional phenoxy groups. Treatment of the bidentate diphenylphosphonite derivative with C6F5MgBr and p-C5NF4MgBr allowed the isolation and full characterization of the comparable bidentate bis(pentafluorophenyl) and bis(p-tetrafluoropyridyl)phosphanes. The ligand properties of the novel bidentate ligand systems were evaluated through the synthesis and vibrational investigation of their tetracarbonyl-molybdenum and cyclopentadienyl-iron complexes. The pi acidity of the synthesized ligands increases in the order methoxy-<phenoxy-<pentafluorophenyl-<p-tetrafluoropyridyl phosphane.
Hoge
Berthold
B
Institut für Anorganische Chemie, Universität zu Köln, Greinstr. 6, 50939 Köln, Germany. b.hoge@uni-koeln.de
Panne
Patricia
P