COMPLEXES OF RHENIUM(V) WITH AMINOACETOPHENONES AND THEIR REACTIONS WITH SOME BIDENTATE LIGANDS

Complexes of rhenium(V) with 2-, 3- and 4-aminoacetophenone (H2aap) have been synthesized. The reaction of trans-ReOCl3(PPh3)2 with 2-H2aap in benzene yielded the imido complex [Re(2-aap)Cl3(PPh3)], in which the oxo oxygen and one of the PPh3 groups were substituted by the dianionic imido nitrogen and the neutral ketonic oxygen, respectively. With 3- and 4-H2aap the imido complexes trans-[Re(aap)Cl3(PPh3)2] were isolated. The monodentate coordination mode of these latter two ligands was authenticated by the X-ray crystal structure of trans-[Re(3-aap)Cl3(PPh3)2]; crystals are triclinic, P1, with a = 10.567(5), b = 11.989(6), c = 18.739(8) A, α= 74.82(4)o, β= 75.27(4)o, γ= 73.15(4)o, U = 2152(2) A3, Z = 2, R = 0.0469. The further reaction of [Re(3-aap)Cl3(PPh3)2] with the bidentate ligands 2-aminophenol and 8-hydroxyquinoline (HL) led to the isolation of complexes of the type [Re(3-aap)Cl2(PPh3)(L)]. However, with 1,2-diaminobenzene (H2dab), the 3-aap imido moiety was displaced by the imido group {N(C6H4)NH2}, to give the complex trans-[Re(dab)Cl3(PPh3)2]. (Bulletin of The Chemical Society of Ethiopia: 2002 16 (2): 149-156)