Ligand Substitution in a Square Planar Complex



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Bromide 1 approaches from the top of the square planar complex, forming the trigonal bypyramidal intermediate. This intermediate can form a cis-[PtCl2Br2]2- or trans-[PtCl2Br2]2- depending on which chloride ligand is removed.

Removal of chloride 2 results in formation of the cis complex, indicated by the 90o orange Br-Pt-Br bonds. Removal of chloride 3 results in formation of the trans complex, indicated by the straight orange Br-Pt-Br bonds.

Inner Sphere Mechanism for Electron Transfer