Blocking ligands, cyanide-bridged complexes

CYANIDE-BRIDGED COMPLEXES OE TRANSITION METALS Possible geometries for complexes with pentadentate blocking ligands L ... 

CYANIDE-BRIDGED COMPEEXES OE TRANSITION METAES Possible geometries for complexes with tridentate blocking ligands... 

A number of similar trinuclear complexes were prepared with Mn(II) using the pentadentate macrocycle maodp as a planar blocking ligand. The reaction between [Mn°(maodp)(H20)2l and [Fe CN)6]" results in the neutral product [Mn maodp)(H20)]2[Fe CN)6] (101). As in the case of the complexes formed with Mn(III) Schiff base building blocks, the H2O molecule coordinated to each peripheral Mn(II) center is arranged trans to the bridging cyanide [Fig. 16(a)]. 

As noted previously, a second large class of cyanide-bridged trinuclear complexes is characterized by a structure in which the central metal ion is either solvated or protected by one tetradentate, two bidentate, or four monodentate blocking ligands (Table IV). In the majority of these compounds, the peripheral building blocks act as donors of bridging cyanides to the central metal ion. 

A nontrivial synthetic approach to multinuclear cyanide-bridged clusters was developed by Comba and co-workers (208), who used ligand XXII capable of encapsulating up to three Cu(II) ions inside the cyclam macrocycles connected to the central triazine ring. In this case, the very nature of the building block promotes the formation of high nuclearity complexes. Indeed, when the [Cu°3(XXII)] ... 

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