Cyanide-bridged complexes

Chemical Reviews paper. We can only discuss a small number of these here, but some important categories are (1) synthetic Fe(II)-Cu(I) complexes and their reactions with O2, (2) oxidized heme-copper models (Fe(III)-X-Cu(II) complexes, where X equals 0x0- and hydroxo-bridged complexes, cyanide-bridged complexes, or other X-bridged complexes), (3) crosslinked histidine-tyrosine residues at the heme-copper center, and (4) Cua site synthetic models. 

Cyanide-bridged complexes involving iron-diimine-cyanide complexes are discussed in Section 5.4.3.5.8. 

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

We present at the end of this section, several isolated examples of trinuclear cyanide-bridged complexes that do not fall within the two major classes of compounds. The first group of such complexes is based on a triangular cluster core. For example, Evans et al., (127) obtained [(Cp )2Sm CNR)( j,-CN)]3 (R = hexyl, tert-butyl) [Fig. 19(a)] from a reductive cleavage of the isocyanide CNR ligand by Cp 2Sm (thf)2. Moreover, the same group later demonstrated the preparation of such trinuclear complexes by isocyanide cleavage with Cp 3Sm ... 

An interesting approach to the preparation of cyanide-bridged complexes involves the use of octahedral [Re6Q8(CN)g]" anions (Q = S, Se, Te) as divergent precursors that are topologically analogous to [M(CN)6]" anions (132). Strictly... 

PhCH2CN to produce benzaldehyde and the cyanide-bridged complex [Cu°2(PD 0)(CN)]2 (C104)4, whose stmcture is based on a square core (Fig. 33). 

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... 

Cyanide-bridged complexes containing more than eight metal centers are relatively rare. These clusters will be considered in this section in the order of increasing nuclearity. 

The discussion of the structural chemistry of multinuclear cyanide-bridged complexes is concluded by considering two related families of compounds, the architecture of which are based on a face-centered cubic (fee) arrangement of transition metal ions. 

The factors that influence the shift of v(C=N) stretches of the cyanide-bridged complexes relative to those of the free CN ligand with v(C=N) = 2080 cm (234), can be understood on the basis of the molecular orbital (MO) diagram of the CN anion (Scheme 2). Upon coordination to a metal ion, the carbon end of the... 

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