Which of the following complexes exhibits the highest paramagnetic behaviour?
where gly=glycine, en=ethylenediamine and bipy =bipyridyl
(At. no. `Ti=22, V=23, Fe=26, Co=27`)

Options

A. `[Co(OX)_(2)(OH)_(2)]^(-)`
B. `[Ti(NH_(3))_(6)]^(3+)`
C. `[V(gly)_(2)(OH)_(2)(NH_(3))_(2)]^(+)`
D. `[Fe(en)(bby)(NH_(3))_(2)]^(2+)`

Answer

A

Explanation

The oxidation state of Co in `[Co(OX)_(2)(OH)_(2)]^(-)` is `+5`. This is not possible. The oxidation state of Ti in `[Ti(NH_(3))_(6)]^(3+)` is `+3`. `Ti^(3+)` has just one unpaired electron. O.S. of 'V' in `[V(gly)_(2)(OH)_(2)(NH_(3))_(2)]^(+)` is again `+3` and it means the number of unpaired electrons is 2. Oxidation state of Fe in `["Fe(en) (bpy) "(NH_(3))_(2)]^(2+)` is `+2`. So it contains 4 unpaired electron. More is the oxidation number of unpaired electron more will be the paramagnetic character.