INFLUENCE OF THE ELECTRONIC EFFECTS OF PHOSPHINE-LIGANDS UPON THE PROPERTIES OF CYCLOPALLADATED COMPLEXES CONTAINING A SIGMA(PD-C-SP(2), FERROCENE)BOND - X-RAY CRYSTAL-STRUCTURES OF C5H5)FE[(ETA(5)-C5H3)C(ME)=N(C6H4-4-ME)])CL(PPH3)] AND PD((ETA(5)-C5H5)FE[(ETA(5)-C5H3)CH2NME2])CL(PPH3)]

The synthesis, characterization and study of the properties of the cyc lopalladated compounds 5)-C5H5)Fe[(eta(5)-C5H3)C(Me)=N(C6H4-4-Me)]}Cl( L)] and [Pd{eta(5)-C5H5)Fe[(eta(5)-C5H3)CH2NMe2]}Cl(L)] (L = PPh3, PPh 2Et, PPhEt2, or PEt3) are reported. The comparison of the electrochemi cal and electronic properties of these compounds has allowed us to elu cidate the influence of the phosphine and chelate ligands upon the env ironment of the Fe-II. As a first approach to clarify the factors affe cting the properties of these complexes, molecular orbital (MO) calcul ations using the PM3(tm) semiempirical method were also undertaken. -C 5H5)Fe[(eta(5)-C5H3)C(Me)=N(C6H4-4-Me)]}Cl(PPh3] (3a) and [Pd{(eta(5)- C5H5)Fe[(eta(5)-C5H3)CH2NMe2]} Cl(PPh3)] (3b) have also been character ized structurally. Complex 3a is triclinic, space group P (1) over bar , with a = 12.795(2), b = 11.534(2) and c = 11.267(2) Angstrom and alp ha = 106.660(10)degrees, beta = 98.660(10)degrees and gamma = 94.500(1 0)degrees; compound 3b is monoclinic, space group P2(1)/a, with a = 13 .650(3), b= 19.678(4) and c= 10.169(2) Angstrom and alpha = gamma = 90 .0 degrees and beta = 94.69(2)degrees. In both cases the molecules con tain a [5,5] bicyclic system formed by a five-membered palladacycle an d the C5H3 ring of the ferrocenyl moiety.