Question
Wed December 06, 2017 By: Anirbanbag81

Which of the following carbonyl will have strongest C-O bond and why ?
 
V(CO)6-
Mn(CO)6-
Fe(CO)5
CR(CO)6
 

Expert Reply
Ramandeep
Thu December 07, 2017
This question is related to the strength of C=O bond in carbonyl. 
CO is a pi acceptor ligand, it accepts electron cloud density from metal centre resulting in synergistic effect which called M→L charge transfer
Stronger the M→CO bond weaker the CO bond strength.
 
Since the manganese complex has a positive metal centre, it is reluctant to give away the electron. As a result, the M→CO bond in the mangnese complex is the weakest.
Hence Mn(CO)6- complex has the strongest C=O bond.
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