Iridium complexes with 2,1,3-benzothiadiazole and related ligands

The reaction of [IrCp*Cl(μ-Cl)]2 (5) with 2,1,3-benzothiadiazole (1) in a 1:1 ratio gives the binuclear complex [Ir2Cp*2Cl4(μ, η2-1)] (6) where 1 acts as a bridging ligand. The 4-XH derivatives of 1 (2, X = O; 3, X = NH) interacted with 5 in various ways. Under basic conditions, 2 and 5 form chelate complexes [IrCp*ClL] (7) (L = C6H3ON2S) (isolated in the form of a co-crystal with the initial 2 and in the individual form, in both cases with solvated toluene) or [Ir2Cp*2Cl3(μ, η3-L)] (8) in the 4:1, 2:1 or 1:1 reactions, respectively. Derivative 3, even with an excess of 5, affords only the mononuclear complex [IrCp*Cl2(3)] (9) where 3 acts as a monodentate ligand, bonded to the Ir center by the ring N atom. A similar complex, [IrCp*Cl2(4)] (10), was also obtained from 5 and acenaphtho[1,2-c][1,2,5]thiadiazole (4) in excess of the former reagent. The structures of complexes 6–10 were confirmed by single-crystal X-ray diffraction.

Graphical abstractIt has been found that a series of thiadiazole heterocyclic compounds act as different coordination mode ligands towards the {IrCp*Cln} (n = 1, 2) moiety in bi- and mononuclear complexes. The structures of the new complexes have been confirmed by single-crystal X-ray diffraction.Figure optionsDownload full-size imageDownload as PowerPoint slide