Unformatted text preview: tal coordination chemistry and have you synthesize a coordination
compound. This synthesis will allow you to experience some of the common procedures
used to prepare and isolate inorganic compounds. The complex you will synthesize is
trans-[Co(en)2Cl2]Cl, a green-colored cobalt transition metal complex, which will be
used to study spectrophotometry and kinetics in the experiments which follow.
The principal oxidation states of cobalt are the +2 and +3 states. The aqueous
[Co(H2O)6]3+ ion is very unstable because it is a powerful oxidizing agent and is readily
reduced by water to [Co(H2O)6]2+:
4 [Co(H2O)6]3+ +2 H2O 4 [Co(H2O)6]2+ + O2 + 4 H+
However, the +3 oxidation state is stabilized by replacing the coordinated water
molecules with less labile ligands such as NH3, NO, CN-, and NH2CH2CH2NH2 (en). A
labile complex exchanges its ligands rapidly. Lability is associated with the d-electron
configuration of the central metal. In general, ligands coordinated to a Co3+ ion do not
dissociate from the Co3+ ion rapidly, and as a consequence, they are not easily replaced
by other ligands. Thus, Co3+ complex...
View Full Document
This note was uploaded on 04/09/2013 for the course CHE CHE 2C taught by Professor Nasiri during the Spring '07 term at UC Davis.
- Spring '07