Porphyrin potassium cyanide

As an example, Fig. 12.3 depicts a Zn-porphyrin-potassium-crown-ether compound for which the coordination mode of the cyanide ligand could not be un-... 

Cyanide is another widely known poison. Cyanide (CN ) usually comes in the form of potassium cyanide (KCN), sodium cyanide (NaCN), or hydrogen cyanide (HCN). The first two are white solid, and hydrogen cyanide is a pungent-smelling gas. Cyanide binds very strongly with a metal ion such as Fe(II), Fe(III), Cu(II), Zn(II), and many others. These ions constitute important portions, that is, the active sites of many enzymes and proteins (Chap. 6). When a cyanide ion binds with a metal ion, the enzyme s function is disrupted. Cyanide that enters into our body almost indiscriminately binds to any metal ions and disrupts their functions, but an especially sensitive place is the last enzyme in the whole series of respiratory chain. The enzyme contains both iron (embedded in the porphyrin as in hemoglobin) and copper. Cyanide binds to both iron and copper in this enzyme, and stops its function, the last step of respiration. What is the result It stops respiration hence it stops the production of bodily energy (ATP). As we talked about in Chap. 3, we need to continuously produce ATP. Otherwise, we would die. 

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