RHODIUM AND IRIDIUM COMPLEXES WITH THE 1-(2-(DIMETHYLAMINO)ETHYL)-2,3,4,5-TETRAMETHYLCYCLOPENTADIENYL LIGAND

Some new Rh(I), Rh(III), Ir(I), and Ir(III) complexes containing the 1-(2-(dimethylamino)-ethyl)-2,3,4,5-tetramethylcyclopentadienyl (Cp(AND)) ligand are described. The bis(ethene) complexes Cp(AND)Rh(C2H4)2 (2) and Cp(AND)Ir(C2H4)2 (3) with a noncoordinating dimethylamino function are synthesized by reaction of [(C2H4)2RhCl]2 with Cp(AND)Li and by reaction of [(COE)2IrCl]2 with Cp(AND)Li/C2H4, respectively. Addition of iodine to 2 or 3 results in the formation of the respective diiodo complexes Cp(AND)RhI2 (4) and Cp(AND)IrI2 (5) with intramolecular amino coordination. In the presence of CO, 4 or 5 can easily be transferred into the carbonyl complexes Cp(AND)RhI2(CO) (6) and Cp(AND)IrI2(CO) (7), respectively, with a noncoordinating amino function. The reverse reaction is successful for both 6 and 7, but under differing conditions. In the reaction of 4 and 5 with PMe3, PPh3, and CNtBu, the corresponding substitution products Cp(AND)MI2L (8-12) are formed. Reduction of 4 and 5 with sodium amalgam under a CO atmosphere leads to the carbonyl complexes Cp(AND)Rh(CO)2 (13) and Cp(AND)Ir(CO)2 (14), respectively, with a noncoordinating amino group. In the reaction of 4 and 5 with Ag2C2O4, the oxalato complexes Cp(AND)RhC2O4 (15) and Cp(AND)IrC2O4 (16), respectively, are formed. The coordinating amino group in 15 and 16 can be replaced by the PMe3 ligand (compounds Cp(AND)(PMe3)RhC2O4 (17) and Cp(AND)(PMe3)IrC2O4 (18)). Structure investigations on 4 (crystal system monoclinic; space group P2(1)/n; a = 8.775(5) angstrom; b = 14.053(6) angstrom; c = 13.880(7) angstrom; beta = 103.64(4)-degrees; Z = 4) and 5 (crystal system monoclinic; space group P2(1)/n; a = 8.828(2) angstrom, b = 14.006(4) angstrom; c = 13.823(4) angstrom; beta = 103.14(2)-degrees; Z = 4) confirm the intramolecular coordination of the dimethylamino group.