FE(CO)2[P(OME)3]2L DICARBONYLBIS(TRIMETHYLPHOSPHITE)IRON COMPLEXES WITH THE LIGANDS L = ETHENE, DIPHENYLETHINE AND SO2

The ethene ligand in Fe(CO)2[P(OMe)3]2(eta2-C2H4) (1) can be substituted by reaction of 1 with diphenylethine leading to formation of the previously known Fe(CO)2[P(OMe)3]2(eta2-C2Ph2) (3). This reaction represents a new path to the hitherto rare mononuclear eta2-alkine iron complexes. Another related compound, Fe(CO)2[P(OMe)3]2(SO2) (4) was found unexpectedly upon reacting 1 with thiophenedioxide, and was prepared subsequently from 1 and SO2. Compounds 1, 3 and 4 have been characterized by crystal structure analyses. Their structures are very similar, having trigonal-bipyramidal coordination of the iron atom and phosphite groups in trans positions. They only differ by the ligands ethene, diphenylethine or SO2 in equatorial positions.