title: P-Amino-cyclopentadienylidene-phosphoranes versus P-cyclopentadienyl-iminophosphoranes--tautomeric protic forms of a new bidentate CpPN ligand system.
abstract: The Staudinger reaction of cyclopentadienyl-phosphanes C5H5-PMe2 (P1), C5H5-PPh2 (P2), and C5Me4H-PMe2 (P3) with azides Me3SiN3, 1-AdN3 (Ad = 1-adamantyl) and DipN3 (Dip = 2,6-diisopropylphenyl) has been studied. The nature of the products depends on the substituents at the C5 ring, at the phosphorus and nitrogen atoms: A series of new P-amino-cyclopentadienylidene-phosphoranes 2-6 was synthesized by reactions of P1-P3 with 1-AdN3 (2-4) and DipN3 (5,6). In contrast, P-cyclopentadienyl-iminophosphoranes 1 and 7 were obtained as predominant tautomers by reaction of less CH-acidic P3 with less N-basic Me3SiN3 and DipN3. Both tautomers are protonated forms of ambident, potentially chelating constrained-geometry ligands. The molecular structures of three members of this "CpPN" ligand family, 3, 4 and 6, are characterized by X-ray crystallography.
authors.affiliation: Fachbereich Chemie der Philipps-Universität Marburg, Hans-Meerwein-Str., 35032 Marburg, Germany.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Petrov
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Rufanov
authors.forename: Burkhard
authors.initials: B
authors.lastname: Ziemer
authors.forename: Petra
authors.initials: P
authors.lastname: Neubauer
authors.forename: Vasily V
authors.initials: VV
authors.lastname: Kotov
authors.forename: Jörg
authors.initials: J
authors.lastname: Sundermeyer