Ligand structures cyanide-bridged complexes

Three types of pentanuclear cyanide-bridged complexes were described, namely, TBPs, cross-shaped clusters, and open chains. As shown by the Dunbar group (173-177), the TBP architecture is amenable to a wide variety of transition metal ions. In fact, neutral complexes of the general formula [M tmphen)2]3[M CN)6]2 were prepared with 22 different combinations of metal ions (Table V). In these structures (Fig. 34), two [M (CN)6] anions occupy the axial positions of the TBP core. Three cyanide ligands of each hexacyanometalate unit act as bridges, whereas... 

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. 

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