O chem Chirality question - 3 groups

[smiley00]

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Hi,

So I get the whole 4 diff groups attached to a carbon = chiral carbon which will rotate light.

My question is if the carbon has 3 different groups attached to it like something including ketone, CH3COH for example...why does this not rotate light?

When I searched online, I found that Nitrogen compounds with 3 groups DO rotate light, but nothing on carbon ...I was just wondering if anyone knows why this happens?

Thanks!😀

 

[ScarletKnight24]

Hi,

So I get the whole 4 diff groups attached to a carbon = chiral carbon which will rotate light.

My question is if the carbon has 3 different groups attached to it like something including ketone, CH3COH for example...why does this not rotate light?

When I searched online, I found that Nitrogen compounds with 3 groups DO rotate light, but nothing on carbon ...I was just wondering if anyone knows why this happens?

Thanks!😀

Not sure what you were asking but a molecule ROTATES light if it is CHIRAL. Just because a molecule has a chiral center, it doesn't mean it will rotate light (ex: meso).

 

[ChiSox]

The answer is resonance.. It's always resonance

 

[mario0923]

Hi,

So I get the whole 4 diff groups attached to a carbon = chiral carbon which will rotate light.

My question is if the carbon has 3 different groups attached to it like something including ketone, CH3COH for example...why does this not rotate light?

When I searched online, I found that Nitrogen compounds with 3 groups DO rotate light, but nothing on carbon ...I was just wondering if anyone knows why this happens?

Thanks!😀

you have to look at the hybridization of the atom
carbonyl carbon is sp2 since it has 3 electron domain
and if sp2 it is not a chiral center therefore there is no rotation

but for nitrogen R-N-H2 it has a lone pair so it has 4 electron domain so it is sp3
it might be a chiral center so it can rotate light

you might study how to figure out the hybridization of atoms because you need to know it for finding out the aromaticity of the molecule too. it is important to identify the hybridization

btw I might be wrong so double check my answers 🙂

 

[smiley00]

Thanks for the answers!

Resonance made me LOL!! and yah i understand the meso thing. I think my question is related more to polarimeters. I just found it odd that a 3 diff groups attached to carbon would not rotate light, but Mario your answer does make sense. 😀