Discrete half-sandwich Ir, Rh-based organometallic molecular boxes: synthesis, characterization, and their properties.

The treatment of binuclear complexes [Cp*(2)M(2)(μ-QA)Cl(2)] (M = Ir, 2a; M = Rh, 2b) (H(2)QA = 1,4-dihydroxyanthraquinone) with pyrazine or bifuncational pyridyl-based ligands (4,4'-dipyridine (bpy), E-1,2-bis(4-pyridyl)ethene (bpe), 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (bpo), and 2,5-bis(4-pyridyl)-1,3,4-thiadiazol (bpt)) in the presence of AgOTf (OTf = CF(3)SO(3)) in CH(3)OH, gave the corresponding tetra-nuclear complexes, with a general formula of Cp*(4)M(4)(μ-QA)(2)(μ-L)(2)(4) (M = Ir, 3a-7a; M = Rh, 3b-7b), respectively. The molecular structure of Cp*(4)Ir(4)(μ-QA)(2)(μ-pyrazine)(2)(4) (3a) has been determined by single-crystal X-ray analysis, revealing that the metal centers were connected by pyrazine and bis-bidentate QA(2-) ligands to construct a rectangular cavity with the dimension of 7.30 × 8.41 × 6.92 Å. Complexes 3a and 3b were found to exhibit selective trapping of halocarbons properties.