diethylamine in dichloromethane T=20°C; 24 h; Inert atmosphereSchlenk technique;

in tetrahydrofuran to soln. of Fe-W complex PPh3 added, mixt. stirred for 2 d at room temp.; mixt. concd. to dryness, residue dissolved, filtered, concd., chromy., first pale yellow band evapd.;

triphenylphosphine in dichloromethane Fe-complex was combined in CH2Cl2 with 1 equiv of PPh3 under Ar, mixt. was stirred at room temp. for 24 h; evapd. under vac., residue hydrolyzed with H2O, filtered, 2 equiv of NH4PF6 added to the filtrate (cationic complex pptd.), ppt. left on the filter was extd. into CH2Cl2, sepd. on an alumina column (Et2O-CH2Cl2); identified by (1)H NMR and IR spectra;

in tetrahydrofuran to soln. of Fe-Mo complex PPh3 added, mixt. stirred for 2 d at room temp.; mixt. concd. to dryness, residue dissolved, filtered, concd., chromy., first pale yellow band evapd.;

in tetrahydrofuran to soln. of Fe-Cr complex PPh3 added, mixt. stirred for 2 d at room temp.; mixt. concd. to dryness, residue dissolved, filtered, concd., chromy., first pale yellow band evapd.;

in dichloromethane Fe-complex was combined in CH2Cl2 with 1 equiv of P(OEt)3 under Ar, mixt. was stirred at room temp. for 24 h; evapd. under vac., residue hydrolyzed with H2O, filtered, 2 equiv of NH4PF6 added to the filtrate (cationic complex pptd.), ppt. left on the filter was extd. into CH2Cl2, sepd. on an alumina column (Et2O-CH2Cl2); identified by (1)H NMR and IR spectra;

in dichloromethane Fe-complex was combined in CH2Cl2 with 1 equiv of PBu3 under Ar, mixt. was stirred at room temp. for 24 h; evapd. under vac., residue hydrolyzed with H2O, filtered, 2 equiv of NH4PF6 added to the filtrate (cationic complex pptd.), ppt. left on the filter was extd. into CH2Cl2, sepd. on an alumina column (Et2O-CH2Cl2); identified by (1)H NMR and IR spectra;

in tetrahydrofuran at room temp., under N2;

in dichloromethane Fe-complex was combined in CH2Cl2 with 1 equiv of cyclohexene under Ar,mixt. was stirred at room temp. for 24 h; evapd. under vac., residue hydrolyzed with H2O, filtered, 2 equiv of NH4PF6 added to the filtrate (cationic complex pptd.), ppt. left on the filter was extd. into CH2Cl2, chromd. on an alumina column (Et2O-CH2Cl2); identified by (1)H NMR and IR spectra;

in ethanol kept at 0°C for 24 h, under N2; crystals sepd., washed with cold ethanol (-78°C) and dried in vac., elem. anal.;