Air oxidation of Ir2(Cl)2(COD)2 revisited. The structures of [Ir(μ2-Cl)(COD)]2(ruby form) and its oxidation product, Ir2Cl2(COD)2(μ2-OH)2(μ2-O)

The reaction of [Ir(COD)(μ 2 -Cl)] 2 (ruby form) ( 1 ) with air in CH 2 Cl 2 solution affords in moderate yield a dinuclear complex of Ir(III), Ir 2 (COD) 2 Cl 2 (μ 2 -OH) 2 - (μ 2 -O)·CH 2 Cl 2 ( 2 ). The compound 1 crystallizes in the orthorhombic space group Pbca with a = 13.631- (4), b = 16.297(5), c = 15.163(4) Å, V = 3368(3) Å 3 , Z = 8. It is a binuclear complex of It(I) with square- planar metal coordination. The two squares share the edge defined by the chlorine atoms. The angle between those planes is 86°. The Cl bridges are symmetrical with a mean ItCl bond length of 2.40114] Å. The Ir··Ir distance is 2.910(1) Å. Compound 2 crystallizes in the orthorhombic space group Cmcm with cell dimensions a = 17.022(4), b = 12.382(5), c = 10.201(4) Å, V = 2150(2) Å 3 , Z = 4. The binuclear molecular complex has a face- sharing bioctahedral configuration with two hydroxyl and one oxo bridging groups. The Ir··Ir distance is 2.868(1) Å.