Living systems coordination compounds

Coordination Compounds in Living Systems Coordination compounds play many important roles in animals and plants. They are also used as therapeutic drugs. 

Most of the reactions the inorganic chemist encounters in the laboratory involve ionic species such as the reactants and products in the reactions just discussed or those of coordination compounds (Chapter 13). However, in the atmosphere there are many free radical reactions initiated by sunlight. One of the most important and controversial sets of atmospheric reactions at present is that concerning stratospheric ozone. The importance of ozone and the effect of ultraviolet (UV) radiation on life has been much discussed. Here we note briefly that only a small portion of the sun s spectrum reaches the surface of the earth and that parts of the UV portion that are largely screened can cause various ill effects to living systems. 

Coordination compounds are found in many places on the earth s surface. Every living system includes many coordination compounds. They are also important components of everyday products as varied as cleaning materials, medicines, inks, and paints. A list of important coordination compounds appears to he endless because new ones are discovered every year. 

Molecules are certainly more varied than life forms. Even carbon-based compounds can be considered as unlimited in number, despite the fact that they almost exclusively involve four bonds around each carbon centre in a very limited number of shapes. When we move to coordination compounds, the range of coordination numbers and shapes is expanded considerably, so that coordination complexes live up to their name - they are inherently complex molecular forms. Fortunately, we can identify a number of basic shapes and even some system that governs outcomes - that is, there is some predictive aspect to shape in coordination complexes. We shall examine complexes from the perspective of coordination number below. 

Coordination compounds are found in living systems and have many uses in the home, in industry, and in medicine. We describe a few examples here and in the Chemistry in Action essay on p. 976. 

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