Allosteric deprogramming of a trinuclear heterometallic helicate.
Two multidentate ditopic ligands L1 and L2 which contain both N-donor and crown ether units have been synthesised. The potentially octadentate ligand L1 forms a trinuclear heterometallic double helicate with Cu(I) and Zn(II) ([Zn2Cu(L1)2](5+)), whereas L2 forms a tetranuclear heterometallic double helicate with the same metal ions ([Zn2Cu2(L2)2](6+)). Both species have been characterised by (1)H NMR, ESI-MS and single crystal X-ray crystallography. Reaction of [Zn2Cu2(L2)2](6+) with Ba(2+) results in the coordination of the crown ether units giving the simple barium coordinated species [Zn2Cu2(L2)2Ba2](10+). However, reaction of [Zn2Cu(L1)2](5+) with Ba(2+) deprograms the ligand and results in the formation of a mixture of species.
Riis-Johannessen
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T
School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK.
Harding
Lindsay P
LP
Jeffery
John C
JC
Moon
Ryan
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Rice
Craig R
CR