Stepwise Formation of Tetra- and Hexanuclear Iridium and Rhodium Complexes Containing Oxalato Ligands

The reactions of [Cp* 2 Ir 2 (μ-η 2 - η 2 -C 2 O 4 )Cl 2 ] 2a and [Cp* 2 Rh 2 (μ-η 2 - η 2 -C 2 O 4 )Cl 2 ] 2b with bidentate ligands such as 4,4‘-bipyridine (bpy) and 2,5-bis(4-pyridyl)-1,3,5-oxadiazole (bpo) in the presence of AgOTf gave the corresponding tetranuclear complexes [Cp* 4 M 4 (μ-L) 2 (μ-η 2 - η 2 -C 2 O 4 ) 2 ](OTf) 4 ( 3a: M = Ir, L = bpy; 3b: M = Rh, L = bpy; 4a: M = Ir, L = bpo; 4b: M = Rh, L = bpo). The reactions of 2a and 2b with tridentate ligand 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) in the presence of AgOTf gave the corresponding hexanuclear complexes [Cp* 6 M 6 (μ-tpt) 2 (μ-η 2 - η 2 -C 2 O 4 ) 3 ](OTf) 6 ( 5a: M = Ir; 5b: M = Rh).