Helo

 

How are you ?

 

My question is in the picture attached .

 

Please clarify the answer .

 

Please explain why the answer .

 

Thank you for forum .

Associative as NO can reversibly act as a 1e or a 3e donor

i don't know correct ans . but acc. to me its n't because of NO but due to formation of pentavalent ( sp3d hybridization ) transition state (as in your case) which acc. to Werner theory is highly unstable so complex again get its tetravalent state .

Unfortunately Vedmecum, it is indeed due to the reversible 1e (bent ) NO and 3e (linear) NO interconversion. There are a number of other ligands which show similar effects eg the indenyl ligand which can flip eta-3 to eta-5. The complexes above are coordinatively unsaturated, the 1e (bent) NO configuration makes them electronically unsaturated 16e species, which then exhibit very low activation energy associative ligand substitution mechanisms

Tartaglia ,may be your ans. is correct to some extent but mine guess was also correct , you can verify it from the following links:-

 

1. http://www.chemguide.co.uk/inorganic/complexions/ligandexch.html

2. http://www.britannica.com/EBchecked/topic/136410/coordination-compound/277812/Substitution#ref=ref1008332

3. pages 706-710 http://books.google.com/books?id=ocKWuxOur-kC&pg=PA701&lpg=PA701&dq=substition+reaction+in+inorganic+chemistry&source=bl&ots=M7v4IiixEZ&sig=BaCbUwt8vT5_f6C5JEwlTC-PG7o&hl=en&ei=5t_mSbTWLsuHkQXy6pWbBw&sa=X&oi=book_result&ct=result&resnum=9#PPA711,M1 . :-)

Vedmecum, The point of the question is the 1e/3e interconversion of the NO ligand. This is a rather common undegraduate organometallic chemistry exam question