933802-70-1Relevant articles and documents
Tetramethyl(perfluoroalkyl)cyclopentadienyl rhodium(III) complexes containing phosphorus and nitrogen monodentate donors. Crystal structure of [(η5 - C5 Me4 C4 F9) Rh (PPr3i) Cl2]
?ermák, Jan,?ádny, Jaroslav,Krupková, Alena,Lopatová, Kate?ina,Vlachová, Alena,Nguyen Thi, Thu Huong,?auliová, Jana,Sykora, Jan,Císa?ová, Ivana
, p. 1557 - 1570 (2007/10/03)
Cleavage of a double μ-halo bridge in complexes [(C5Me4CnF2n+1)RhX2]2 (n = 4, 6; X = Cl, Br) with two-electron monodentate P-donors like phosphines or phosphites or monodenate N-donors like pyridine-derived heterocyclic amines gave mononuclear Rh(III) complexes of piano-stool type [(C5Me4CnF2n+1)RhX2L] (L = two-electron donor). Crystal structure of [(η5 - C5 Me4 C4 F9) Rh (PPr3i) Cl2] was determined by X-ray diffraction. The compound had a pseudo-tetrahedral ligand arrangement around the Rh atom. The perfluoroalkyl chain was averted from the phosphine ligand but not completely; after projection to the ring plane the P- (ring centroid) -CF2 angle was around 166°. In contrast to their Cp* analogs, the pyridine complexes were stable in solution at room temperature. Free rotation of triarylphosphine ligands around Rh-P bond and 2-substituted pyridine ligands around Rh-N bond was hindered, giving the values of ΔG? = 14.8 ± 0.1 kcal mol-1 at 27 °C and ΔG? = 14.9 ± 0.1 kcal mol-1 at 52 °C for tri(m-tolyl)phosphine and quinoline complexes, respectively, as followed from the analysis of variable temperature NMR spectra. In the 2-methylpyridine complex, the hindered rotation was accompanied by a reversible decoordination of the ligand at higher temperatures.
