title: Solid-state distortions of linear mono-, bi-, and trimetallic bis(tri-n-butylphosphine) nickel and palladium complexes having 1,4-tetrafluorophenylene bridges as observed via 31P CP/MAS NMR spectroscopy.
abstract: 31P CP/MAS NMR spectra were recorded for a series of eight linear mono-, bi-, and trimetallic bis(tri-n-butylphosphine) nickel and palladium complexes having 1,4-tetrafluorophenylene bridges. A2 type spectra were obtained with Ni(PBu3)2(1,4-C6F4H)2 (I), Pd(PBu3)2(1,4-C6F2) (V) and [Pd(PBu3)2(1,4-C6F4H)]2(1,4-C6F4) (VII). AB type spectra were obtained with Ni(PBu3)2(1,4-C6F4H)Br (II), [Ni(PBu3)2(1,4-C6F4)Br2 (III) and [Pd(PBu3)2Cl]2(1,4-C6F4) (VI). The 2JPP scalar coupling constants fell in the region of 300 to 450 Hz as expected for P-metal-P pairs in a trans configuration. The spectra of [Ni(PBu3)2]3(1,4-C6F4)2Br2 (IV) and [Pd(PBu3)2]3(1,4-C6F4)2Cl2 (VIII) consisted of overlapping A2 and AB spins systems. Large upfield and downfield shifts were measured in the solid samples relative to the corresponding 31P NMR spectra in CDCl3 solution. Correlating the 31P CP/MAS NMR data with reported X-ray crystallographic measurements revealed that both the chemical inequivalence and the solid versus solution resonance frequency shifts were the result of ring current effects brought about by distortions from square-planar geometry at the metal centre in the solid state.
authors: Department of Chemistry and Erindale College, University of Toronto, Ontario, Canada.
authors: P M
authors: PM
authors: Macdonald
authors: A D
authors: AD
authors: Hunter
authors: G
authors: G
authors: Lesley
authors: J
authors: J
authors: Li
mesh_terms: D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D010759:Phosphorus Isotopes
chemical_list: D010759:Phosphorus Isotopes; D010165:Palladium; D009532:Nickel