in tetrahydrofuran under N2; to the Fe-complex was added (during 45 min; exclusion of light; -78°C) a suspension of (Ph3C)PF6; mixt. warmed to room temperature during 90 min, stirred for 3 h; addn. of pentane; mixt. stored for 2 d at room temperature; ppt. washed with pentane, dried in vacuo; filtrate evaporated in vacuo; Ph3CH removed by destillation at 180-184°/2 Torr; elem. anal.;