Anticrowns mercury-containing

The X-ray crystal structures of the related, though less complex, anticrown mercury-containing macrocycles 45 and 46 have also recently been reported. Complex 45 may form either 1 1 complexes with Br or I" or a 3 2 complex with Cr. In the case of the bromo derivative, crystallographic results reveal an infinite chain of alternating Br and 45 with each halide bridging between six Hg atoms, Hg- Br 3.07-3.39 A. It is postulated that the related 3 2 chloride complex exhibits a similar, though finite layered structure. The related pentameric species 46 forms... 

More recent work has yielded another class of carborane-based mercury-containing macrocycles 43 and 44 related to crown ethers such as I2-crown-4 and 9-crown-3. Anticrown 43 associates with one or two moles of lithium halide, depending on conditions. The X-ray crystal structure of the chloride salt is shown in Figure 15. 

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