SYNTHESIS AND DYNAMIC SOLUTION BEHAVIOR OF 2,2′,5,5′-TETRAKIS (TRIMETHYLSILYL)-3,3′,4,4′-TETRAMETHYL-1,l′-DIPHOSPHAFERROCENE

2,2′,5,5′-Tetrakis(trimethylsilyl)-3,3′,4,4′-tetramethyl-1,-1′diphosphaferrocene (5) has been obtained from the reaction of 1-phenyl-2,5-bis(trimethylsilyl)-3,4-dimethylphosphole with lithium followed by FeCl2. In solution, the barrier to ring rotation (ΔG∗∗) of 12.5 kcal/mole can he estimated from variable-temperature 1H-NMR spectroscopy.