A HOMOLEPTIC MONONUCLEAR IRIDIUM(II) ORGANOMETALLIC COMPLEX - SYNTHESIS AND X-RAY STRUCTURE OF [IR(C6CL5)4]2-

The homoleptic iridium(II) dianionic complex [Ir(C6Cl5)4]2- has been prepared from [{Ir(mu-Cl)(cyclooctene)2}2] and Li(C6Cl5) in Et2O at -50-degrees-C. It reacts with carbon monoxide affording the iridium(I) complex [Ir(C6Cl5)3(CO)]2-. Both dianionic complexes have been fully characterized by elemental analyses, by MS, and by several physical properties. The crystal structure Of [PBzPh3]2[Ir(C6Cl5)4].CH2Cl2 (1) has been established by an X-ray diffraction study. 1 crystallizes in the monoclinic space group C2/c with a = 19.355(8) angstrom, b = 18.188(6) angstrom, c = 22.691(9) angstrom, beta = 102.82(2)-degrees, v = 7789(5) angstrom3, Z = 4, mu = 25.53 cm-1, and d(calc) = 1.690 g.cm 3. The anionic iridium(II) complex has an imposed C2 symmetry with the 2-fold axis bisecting two pentachlorophenyl groups. The coordination around the Ir atom is almost perfectly square planar. The dispositions of the aryl rings with respect to the metal coordination plane are all inclined in the same way conforming a propeller-like shape for the iridium(II) complex.