n-BuLi in tetrahydrofuran; hexane under Ar; FeCl2 added at 0°C to stirred suspn. of (C5Me5)Li in THF; stirred (1 h); cooled to -78°C; suspn. prepared from n-BuLi inn-hexane and HSEt at 0°C added; 1 h at -78°C; warmed to r oom temp. with stirring overnight; evapd. to dryness; purified by column chromy. (neutral alumina, n-hexane); insol. solid washed with H2O (Fe); elem. anal.;