Chemistry of iridium carbonyl cluster complexes. Synthesis and x-ray crystal structure of [PPh4]2[Ir12(.mu.-CO)5(CO)19], containing an unprecedented metal skeleton

The new dodecanuclear carbonyl cluster [Ir 12 (CO) 24 ] 2- can be prepared in good yields by thermal treatment of [Ir 6 (CO) 15 {Cu(NCMe)}] - in refluxing tetrahydrofuran: the anion has been characterized as the tetraphenylphosphonium salt by a crystallographic study. [PPh 4 ] 2 [Ir 12 (CO) 24 ] crystallizes in the triclinic space group P1 with cell constants a=14.614(5) A, b=25.435(6) A, c=11.977(5) A, α=90.30(3) o , β=112.94(3) o , γ=104.33(2) o , V=3946(5) A 3 , and Z=2