Synthesis and structural characterization of half-sandwich iridium macro-metallacycles containing 1,5-dihydroxy-9,10-anthraquinone ligand

摘要

Treatment of binuclear complex [Cp* _2Ir _2(μ- dhaq)Cl _2] (H _2dhaq = 1,5-dihydroxy-9,10-anthraquinone) with pyrazine or bifuncational pyridyl-based ligands (4,4′-bipyridine (bpy), E-1,2-bis(4′-pyridyl)ethene (bpe), and 2,5-bis(4′-pyridyl)- 1,3,4-oxadiazole (bpo)) in the presence of AgOTf (OTf = CF _3SO _3) in CH _3OH, gave the corresponding tetranuclear complexes, with a general formula of [Cp* _4Ir _4(μ-dhaq) _2(μ-L) _2](OTf) _4 (2a-2d), respectively. The molecular structure of [Cp* _4Ir _4(μ-dhaq) _2(μ-pyrazine) _2](OTf) _4 (2a) has been determined by single-crystal X-ray analysis, revealing that the metal centers were connected by pyrazine and bis-bidentate dhaq ~(2-) ligands to construct a "slope" rectangular cavity with the dimension of 7.4 × 8.8 × 6.9. 2a also exhibited unique properties in host-guest behavior.