Iridium(I), iridium(iii), and iridium(v) complexes containing the (2-methoxyethyl) cyclopentadienyl ligand

Abstract

Treatment of [Ir(μ-Cl)(COE)2]2 (1) with LiCpO gives Ir(η5-CpO)(COE)2 (2; CpO = C5H4(CH2)2OCH3, COE = cis-cyclooctene), which reacts with X2 to afford the iridium(III) derivatives [Ir(η5-CpO)X(μ-X)]2 (X = I (3), Cl (4)). Complexes 3 and 4 react with PiPr3 to yield the corresponding species Ir(η5-CpO)(PiPr3)X2 (X = I (5), Cl (6)), which by addition of LiHBEt3 give Ir(η5-CpO)(PiPr3)H2 (7). The reactions of 5 and 6 with 2.0 equiv of AgBF4 in acetonitrile lead to [Ir(η5-CpO)(PiPr3)(NCMe)2][BF4]2 (8). Treatment of 3 with 2.0 equiv of HSiEt3 per iridium affords the monohydride dimer [Ir(η5-CpO)I]2(μ-H)(μ-I) (9). Complex 4 reacts with 4.0 equiv of HSiEt3 per iridium to give the iridium(V) silyl trihydride derivative IrH3(η5-CpO)(SiEt3) (10), which in the presence of excess of HSiEt3 is transformed into IrH2(η5-CpO)(SiEt3)2 (11). Treatment at −40 °C of 4 with 2.0 equiv of HSiEt3 per iridium leads to a mixture of the hydride dichloro triethylsilyl complex IrH(η5-CpO)Cl2(SiEt3) (12), the dihydride chloro triethylsilyl compound IrH2(η5-CpO)Cl(SiEt3) (14), and the monohydride dimer [Ir(η5-CpO)Cl]2(μ-H)(μ-Cl) (16). Complex 16 has been also prepared by reaction of 4 with 1.0 equiv of HSiEt3 per iridium. Complex 10 is easily deuterated in C6D6 at 80 °C. The X-ray structures of 4, 8, and 9 are also reported.