Metal ?-Complexes of Benzene Derivatives. Part 38. Pentaphenyltriphosphane(5) as a Chelating η12-Ligand. Unusual Formation of an Interannular-(PPh)3-Bridge at Bis(benzene)chromium

Article abstract of DOI:10.1002/hlca.19910740813

<(1-6):(1'-6')-η-Pentaphenyltriphosphane(5)>chromium (8), which is formed from bis(lithio-η⁶-benzene)-chromium and dichlorophenylphosphane, and which is prepared more rationally from bis(chloro-η⁶-benzene)-chromium and K2P3Ph3, is the first sandwich complex featuring an interannular oligophosphane bridge-(PPh)n-, n >/= 2; 31P(1H)- and 1H-NMR spectra suggest that the stereoisomer 8-meso, is formed exclusively and that the -(PPh)3-link in this triphospha<3>chromocyclophane is non-fluxional in the range 193 < T < 348 K.