Metal cyanide chains

HRP C contains two different types of metal center (i.e., iron(III) protoporphyrin IX-heme group and two calcium atoms) that are fundamental for the integrity of the enzyme. The heme group is attached to the enzyme at His 170 by a coordinate bond between the histidine side-chain NE2 atom and the heme iron atom. The second axial coordination site is unoccupied in the resting state of the enzyme but available to hydrogen peroxide during enzyme turnover. Small molecules such as carbon monoxide, cyanide, fluoride, and azide bind to the heme iron atom at this distal site, giving six-coordinated PX complexes. 

Arylmethyl chlorides or bromides are quite reactive compounds that are readily available or easily prepared, and as a result they are useful intermediates for the synthesis of other side-chain derivatives. Thus phenylmethyl chloride can be hydrolyzed to phenyl methanol, converted to phenylethanenitrile with alkali-metal cyanides, and oxidized to benzenecarbaldehyde (benzaldehyde) ... 

Metal ions having coordination number two occur in Hg(CN)2, [Ag(CN)2]- and [Au(CN)2]-, all derivatives of d ° species in each case the structure is linear. In K[Cu(CN)2] the copper atom is actually three-coordinated, the anion being an infinite chain each copper has a carbon atom of an unshared cyanide, and a carbon atom and a nitrogen atom of shared cyanides, as nearest neighbours in approximately planar coordination. Three-coordination also occurs in the [Hg(CN)3]- ion, but there are weak interactions between two of the nitrogen atoms and mercury atoms of other anions, giving rise to a loosely bonded chain structure. 

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... 

The toxic effect of cyanide is attributed predominantly to the production of anoxia following inhibition of the metal-containing enzymes. The critical interaction appears to be the inhibition of the terminal respiratory chain enzyme, cytochrome oxidase as (containing iron) within the mitochondria. The enzyme is essential for the production of adenosine triphosphate (ATP). As a result, aerobic oxidative... 

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