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The double-helical complex [Ni2(spy)2][PF6]4 of the hexadentate ligand 2,2′:6′,2″:6″,2‴:6‴,2‴′:6‴′,2‴″-sexipyridine (spy) is readily prepared in good yield in a nickel(0) templated coupling of 6-bromo-2,2′:6′,2″-terpyridine. The free ligand is obtained in quantitative yield by demetallation of this complex with cyanide.
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Constable et al. (1992) studied this question.
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