N-Acetyl-N,N-dipyrid-2-yl (cyclooctadiene) rhodium (I) and iridium (I) complexes: Synthesis, X-ray structures, their use in hydroformylation and carbonyl hydrosilylation reactions and in the polymerization of diazocompounds

The synthesis of novel N-acetyl-N,N-dipyrid-2-yl complexes of Rh^I and Ir^I, i.e. [RhCl(CH₃CONPy₂)(COD)] (1) and [IrCl(CH₃CONPy₂)(COD)] (2), respectively, is described. Upon prolonged treatment in CH₂Cl₂ at room temperature, complex 1 is transformed into a cationic Rh-complex, i.e. [Rh(CH₃CONPy₂)(COD)⁺RhCl₂(COD)⁻] (1a). Compound 1a crystallizes in the monoclinic space group P2₁/c, complex 2 crystallizes in the triclinic space group . Compound 1 was investigated for its catalytic activity in the hydroformylation of cyclooctene as well as of 1-octene. In addition, 1 was used in various carbonyl hydrosilylation reactions of both aldehydes and ketones. There, turn-over numbers up to 50 000 and yields in the range of 85-100% were observed. Finally, compound 1 was successfully used for the polymerization of N₂CHCOOEt yielding highly stereoregular poly(ethoxycarbonylcarbene) with M_w = 67 000 g/mol and a polydispersity index (PDI) of 2.59.