Nitrates, anionic linkers

Materials based on 4,4 -bipyridine are one of most extensively explored coordination polymer systems. Reaction of Ni(N03)2 and 4,4 -bipyridine affords two products [Ni2(N03)4(4,4 -bipyridine)3]oo depending upon whether the reaction is conducted in methanol or ethanol solution[187]. In both materials the charge on Ni(II) is neutralised by coordinated nitrate anions, and the resultant Ni(N03)2 centre is connected by three ditopic 4,4-bipy linkers to form a T-shaped node (Fig. 19a). In the product obtained from methanol solution, T-shaped units form a 1-D ladder structure, and these ladders run parallel (material M). In the case of the product isolated from ethanol, T-shaped units give an interlocked 2-D bilayer product (material E). The common characteristics for these two materials are that the interactions between the ladders or the layers are relatively weak and this results in dynamic stmctures in which the interactions and distances between ladders or layers are modulated as adsorbate molecules enter the framework [187]. Although... 

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