Question

Which of the following complexes
exhibits the highest paramagnetic
behaviour?where, gly = glycine,
en = ethylenediamine and bpy =
bipyridyl moities)
(At no Ti = 22, V = 23, Fe = 26, Co = 27]
1) [V(gly)2(OH)2(NH3)2]+
2) [Fe(en)(bpy)(NH3)2]2+
3) [Co(OX)2(OH)2]–
4) [Ti(NH3)6]3+

Answer 1

ox and H2O are weak field ligands. They do not cause pairing of electrons. Hence, there is the presence of unpaired electrons.

NH3, bpy, en etc are strong field ligands.

Since both ligands in option 3 are weak, least pairing and hence greater no of unpaired electrons will be present. Other complexes contain at least 2 strong field ligands.

If you want, you can use orbital diagram method too, but if you reason like this then it is easier.

Answer 2

Explanation:

Pairing does not occur in v +5  and it has maximum number of unpaired electrons and highest paramagnetic

                    Hope you understand