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Self‐Assembled Hexanuclear Organometallic Cages: Synthesis, Characterization, and Host–Guest Properties
Author(s) -
Han YingFeng,
Li Hao,
Zheng ZhiFang,
Jin GuoXin
Publication year - 2012
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201100999
Subject(s) - chemistry , supramolecular chemistry , coronene , organometallic chemistry , crystallography , electron donor , ferrocene , pyrene , electron acceptor , heteronuclear molecule , triazine , stereochemistry , nuclear magnetic resonance spectroscopy , molecule , photochemistry , crystal structure , polymer chemistry , organic chemistry , electrochemistry , catalysis , electrode
A series of iridium‐ and rhodium‐based hexanuclear organometallic cages containing 2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinone, 9,10‐dihydroxy‐1,4‐anthraquinone, and 6,11‐dihydroxynaphthacene‐5,12‐dione ligands were synthesized from the self‐assembly of the corresponding molecular “clips” and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine ligands in good yields. These organometallic cages can form inclusion systems with a wide variety of π‐donor substrates, including coronene, pyrene, [Pt(acac) 2 ], and hexamethoxytriphenylene. The 1:1 complexation of the resulting supramolecular assemblies was confirmed by 1 H NMR spectroscopy. Large complexation shifts (Δ δ >1 ppm) were observed in the 1 H NMR spectra of guests in the presence of cage [Cp* 6 M 6 (μ‐DHNA) 3 (tpt) 2 ](OTf) 6 ( 6a ; M=Ir, tpt=2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine). The formation of discrete 1:1 donor–acceptor complexes, pyrene ⊂6 b (M=Rh), coronene ⊂6 a , coronene ⊂6 b , and [Pt(acac) 2 ] ⊂6 a was confirmed by their single‐crystal X‐ray analyses. In these systems, the most important driving force for the formation of guest–host complexes is clearly the donor–acceptor π⋅⋅⋅π stacking interaction, including charge‐transfer interactions between the electron‐donating and electron‐accepting aromatic components. These structures provide compelling evidence for the existence of strong attractive forces between the electron‐deficient triazine core and electron‐rich guest. The results presented here may provide useful guidance for designing artificial receptors for functional biomolecules.