Image source: google
Nowadays transition metals have a large number of applications in organic chemistry. They are chosen because of their capacity to form complex compounds. They are also used in medicinal chemistry and synthetic organometallic compound formation. Most of them show colour and different magnetic properties upon interacting with ligands.
Now the question is why transition metals are chosen??
Because of their tendency to form complex compounds, transition metals are suited for creating various organic compounds known as Organometallic compound. Most of them, especially the ones with Iron and Cobalt are essential for biological activities in living organisms.
Iron
---------
Oxygen plays a vital role in the oxidation of glucose in the human body. Oxygen is carried in the human body by haemoglobin and myoglobin present in the blood. Now a major part of this'heme' group is constituted by iron complexes. For nitrogen protoporphyrin IX are coordinated with Fe2+ ion and produce uncharged 'haemo'.
Another application of iron complexes is in cytochrome which contains 'heme' like prosthetics groups. Thye exists in the membranes of mitochondria, chloroplast and acts as electron transfer agents. Iron(Fe) make fifth coordination with imidazole nitrogen of protein histidyl unit and sixth coordinate with sulphur of a methoxyl side chain of the protein.
structure of haemoglobin, heme group, myoglobin
Image source: Google
Cobalt
----------
Cobalt exists in cobalamines and coenzymes as Co3+, which takes part in such complex formation. Octahedral geometry is formed by the help of four 'pyrrole' and 'imidazole' nitrogen atoms. Co3+ is essential for Vitamin B12 and coenzymes.
Structure of vitamin B12
Image source: Google
Commentaires