IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

Aatish

Plz explain which is more stable

CF₃⁺ or CF₃CH₂⁺

kiran

Hi

CF₃CH₂⁺ is more stable than CF₃⁺ Because of :

1) Secondary carbocation is more stable than primary.

2) -I effect of Flourine makes Carbon atom of CF₃⁺ more positive than the Carbon atom of CF₃CH₂⁺.

Njoy!

mukul1yellow9

no.. CF3 MORE STABLE..B,COZ OF BACK BONDING...

Aatish

I agree with u mukul ans is this only , but plz let me know what is back bonding ?

And how does it explians the stability of CF₃⁺

Thanks.........

priyankamalviya

mukul is right..more stability of sec. carbocat is not taken into account here

mayur1412

cf_{3^{+
is more stable...bcoz in cf}3}_^ch2_{^{+ the -I grup of cf3 wud increase da electron density..on carbon.. hence due to more electron density ..cf3ch2...wud be less stable..!}}

magiclko

yeah the reason given by mayur and mukul both are right, mukul's being the more dominant one!!!

Here's what back-bonding is

In pi backbonding, also called pi backdonation ,electrons move from an atomic orbital on one atom to a pi* anti-bonding orbital on another atom or ligand. It is especially common in the organometallic chemistry of transition metals with multi-atomic ligands such as carbon monoxide, ethylene or the nitrosonium cation. Electrons from the metal are used to bond to the ligand, in the process relieving the metal of excess negative charge

The electrons are taken from a d-orbital of the metal, and usually placed into an anti-bonding molecular orbital of the ligand, which causes the bond order of that ligand to decrease. This leads to a decrease in the vibrational frequency of the bond, which can be measured using IR spectroscopy. Although the bond-order within the ligand is decreased by this process, the metal - ligand bond-order is increased.

Compounds where ? backbonding occurs include Ni(CO)₄

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