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

摘要

The treatment of binuclear complexes [Cp*_2M _2(μ-QA)Cl_2] (M = Ir, 2a; M = Rh, 2b) (H_2QA = 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_3SO_3) in CH_3OH, gave the corresponding tetra-nuclear complexes, with a general formula of [Cp*_4M_4(μ-QA) _2(μ-L)_2](OTf)_4 (M = Ir, 3a-7a; M = Rh, 3b-7b), respectively. The molecular structure of [Cp*4Ir 4(μ-QA)2(μ-pyrazine)2](OTf)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 ?. Complexes 3a and 3b were found to exhibit selective trapping of halocarbons properties.