Synthesis and characterisation of iron and cobalt complexes with phosphinothiolate ligands

Abstract

Neutral iron complexes of a series of arenephosphinothiol proligands, Ph x P(ArSH) 3− x , ( x=0–2, Ar=C 6H 4, C 6H 3SiMe 3) have been synthesised. Compounds [Fe{2-(Ph 2PO)C 6H 4S} 3] ( 1), [Fe{2-(Ph 2P)-6(Me 3Si)C 6H 3S} 3] ( 2), [Fe{2-(Ph 2PO)-6(Me 3Si)C 6H 3S} 3] ( 3) and [Fe 2{PhP(C 6H 4S-2) 2} 3] ( 4) were obtained most conveniently by the electrochemical oxidation of an iron anode in a cell containing an acetonitrile solution of the corresponding proligand. [Fe{2-(Ph 2P)C 6H 4S} 2(CO) 2] ( 5) was obtained by the addition of the appropriate proligand to an acetonitrile solution of FeCl 2 saturated with CO. The reaction of FeCl 2 with PhP(C 6H 4SH-2) 2 in methanol in the presence of CO and bis-diphenylphosphinoethane (dppe) gave [Fe{PhP(C 6H 4S-2) 2}(dppe)(CO)] ( 6) in good yield. The reaction of FeCl 2 with the potentially tetradentate P(C 6H 4SH-2) 3 proligand in presence of PMe 2Ph or dppe allows the synthesis of [Fe{P(C 6H 4S-2) 3}(PMe 2Ph) 2] ( 7) and [Fe{P(C 6H 4S-2) 3}(dppe)] ( 8). Corresponding reactions of the phosphinothiolates with CoCl 2 in the presence of CO and/or phosphine ligands gave [CoCl{PhP(C 6H 4S-2) 2}(dppe)] ( 9), [Co{PhP(C 6H 4S-2) 2}(dppe)(CO)]BPh 4 ( 10), [Co{PhP(C 6H 4S-2) 2}(dppe) ] ( 11), [Co(P(C 6H 4S-2) 3L] (L=dppe, 12, L=PMe 2Ph, 13. The X-ray crystal structures of complexes 2, 4, 7 and 8, are discussed.