56687-32-2Relevant articles and documents
Chemical Synthesis with Metal Atoms. The Preparation and Structure of Cyclo-octadiene Trifluorophosphine Complexes of Chromium. The Crystal Structure of (η5-Cyclo-octa-1,3-dienyl)hydridotris(trifluorophosphine)chromium
Blackborow, J. Richard,Eady, Colin R.,Grevels, Friedrich-Wilhelm,Gustorf, Ernst A. Koerner von,Scrivanti, Alberto,Wolfbeis, Otto S.
, p. 661 - 667 (1981)
The reaction of cyclo-octa-1,5-diene (1,5-cod), PF3, and chromium atoms produces (1) and (2).The use of 1,3- rather than 1,5-cod produces only (2) under the same conditions.Complex (1) is readily converted into (2) by heating (90 deg C, in toluene).The preparation of (3) from 1,3- or 1,5-cod is also described.The structure of (2) was determined by X-ray crystallography.The compound crystallizes in the orthorhombic space group Pbca with a=13.452(3), b=14.419(4), c=15.268(3) Angstroem, and Z=8.The final R value was 0.065 9 for 1 699 observed reflections. The structure is retained in solution below - 80 deg C, but is shown by 13C and 1H n.m.r. spectroscopy to become fluxional upon warming.There are two distinct exchange processes; one results in pairwise coalescence of the 13C and 1H resonances; the other finally leads to a set of only two 1H signals with an intensity ratio of 8:4, thus indicating equivalence of the eight ring positions.
