The role of the 2,4,6-tris(trifluoromethyl)phenyiamino group in stabilizing new phosphorus-, arsenic-, and germanium-containing main-group compounds and transition-metal derivatives

Article abstract of DOI:10.1002/cber.19971300813

The reactions of potassium R_f-amide [R_f = tris(trifluoromethyljphenyl] (2) with PCl₃, AsCl₃, and GeCl₂·dioxane yield new four-membered inorganic heterocycles [R_fNPCl]₂ (3), [R_fNAsCl]₂ (4), and [R_fNGe]₂ (5), respectively. On the other hand, the reaction of R_f-amide 2 with two equivalents of R_fPCl₂ leads to the formation of the imino-λ³-phosphane R_fN=PR, (6) and the diamino-λ³-phosphane (R_fNH)₂PR_f (7). The iminophosphane 6 reacts with Ni(CO)₂(PPh₃)₂ and forms the complex [Ni(PPh₃)₂(R_fN=PR_f)] (9), in which the iminophosphane coordinates to the metal through the phosphorus lone pair. Treatment of lithium amide 2 with transition metal chlorides ZnCl₂ and FeCl₂ yields the imido/amido spirocyclic metal derivatives 9 and 10, respectively. Compounds 3-10 have been extensively characterized by their analytical and mass, IR, and NMR (¹H, ¹⁹F, and ³¹P) spectroscopy. Further, the molecular structures of all the compounds have been unambiguously determined by single-crystal X-ray diffraction studies. The diazadigermetidine 5 crystallizes in a fluorescent-yellow orthorhombic and a yellow monoclinic crystal modification. The results obtained reveal the role of Rf group in stabilizing new multiple bonded systems and inorganic heterocycles. A skeletal rearrangment of the R_f ligand is observed in the reactions leading to compounds 9 and 10. Moreover, the preparation of compounds 9 and 10 indicates the limitation of the use of this ligand in the preparation of new metal-amide systems, especially where the metal atoms have a strong tendency for the formation of strong M-F bonds. VCH Verlagsgesellschaft mbH.