Chemistry PPT

1. REACTION MECHANISM OF TRANSITION METAL COMPLEXES-I
UNIT-1
1
Presented by :
Dr. K. NAGARAJ
Assistant Professor
Institute of Science and Research

2. Complexes in which exchange of one or more ligands
are rapidly exchanged are called labile complexes.
 If the rate of ligand exchange is slow then the
complex is said to be inert.
 Lability is not related to the thermodynamic
stability of a complex.
 A stable complex may be labile or inert , so as the
unstable complex .
LABILITY AND INERTNESS

3. [Cu(NH3)4(H2O2)2]2+ is labile. Its aqueous solution
is blue in color.
When concentrated hydrochloric acid is added to
this solution, the blue solution immediately turns
green ,giving [CuCl4]2- .
 But when the complex is kept as such it remains as
such with out any decomposition (i.e stable)
LABILE AND STABLE COMPLEX

4.  [Co(NH3)6]3+ reacts slowly. When this
complex is treated with concentrated HCl, no
reaction takes place.
 Only when it is heated with 6M HCl for many
hours, one NH3 is substituted by Cl- .
[Co(NH3)6]3+ + HCl [ → Co(NH3)5Cl]2+ + NH4
+
INERT AND UNSTABLE COMPLEX

5. ENERGY PROFILE DIAGRAM : INERT AND LABILE COMPLEX

6.  Size of the central metal ion Smaller the size
of the metal ion, greater will be the inertness
because the ligands are held tightly by the metal
ion.
 Charge on the central metal ion Greater the
charge on the metal ion, greater will be the
inertness of the complex. Since the M-L bonds
are stronger.
FACTORS AFFECTING LABILITY OF COMPLEXES

22. 22

23. 23

24. 24

32. 32

33. 33

42. 42