29CF3 will make the ring acidic
as CF3 is a deactivator
and due to negative hyperconjugation it withdraws electrons
so second one is more acidic than first and hence a weaker base
10 Answers
29
23second is less basic , write the conjugate acid of the given compds, u will understand , keeping in mind that CF3 is even more e- withdrawing tan F , and CH3 is activating
1yes the 2nd is weaker base due to following reasons
1.- I effect of F
2. hydrogen atom on the O is in intramolecular hydrogen bonding with the flourine.
1in da 1st case.... CH3 is an electron releasing grout and phenol is resonance stabilized causing the delocalization of pi-electrons throughout the ring... hence it is more basic.....
but in 2nd case..... CF3 will act as e acceptor due to -I effect of F.... hence electron cloud inside the ring is decreased....... therefore it is more acidic.....
39@above : the ortho effect is only possible for bulkier acid groups such as -COOH. It does not function to such an extent in -OH.
49
+I effect of CH3 stabilises that resonating structure of the conjugate base...
-I effect of CF3 de-stabilises the resonating structure of the CB
thus ortho methyl phenoxide is stabler than ortho trifyl phenoxide (hope that is the correct name) 1,1,1-trifuloromethyl phenoxide
thus orthomethylphenol is more acidic than orthotrifylphenol
11st will be more acidic becoz of hyper conjugation and ortho effect will also take place
39@harrys : What you call the "ortho effect" is not what you're trying to depict. The "ortho effect" is a term for a steric effect which occurs due to bulky acid groups attached to an aromatic ring, with bulky ortho-substituted groups. What you're possibly trying to say is "chelation", or "temporary ring formation" due to H-bonding.
