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pop000 · Jan 18, 2011, 12:36 AM

Which of the following materials have activity Optical ?

I know That we must have carbon with four different substituents,different groups attached to each carbon - if there is four,so we have chiral molecule.

But I am not see here any carbon with four different substituents/different groups attached to each carbon in any of the following materials.
Is this rule is acceptable when there an double covalent bond like in A,E ?

Thanks for help :)

DrBob1 · Jan 18, 2011, 06:33 AM

Look at your structure "A". Carbon number 2 has (1) H, (2) OH, (3) CH3 and (4) COOH attached to it. Which don't you understand -- "four" or "different"?
All the examples have a chiral carbon except one of them (another has TWO chiral centers). Respond with your new tries.

Unknown008 · Jan 18, 2011, 08:00 AM

No, we don't count double bonds.

Maybe something which can help you, is to draw again these structures, but in full expanded form, that is showing all the bonds present so that you don't miss any.

pop000 · Jan 18, 2011, 08:25 AM

Well I see in A only one carbon atom it have double bonds with O one bond with OH and one bond with CH.

When you say carbon 2 you mean the carbon that it part of CH in the left side? (not the CH3) id yes so there I see that it have bond with CH3 H OH but how did you get COOH?

By the way there an Option UPLOAD new picture to this Discussion?

Thanks to both of you.

Unknown008 · Jan 18, 2011, 08:34 AM

Here is how he got COOH and the rest:

As you can see, I expanded the bonds around the carbon atom I'm interested in, and you see clearly that there are 4 different groups of atoms attached to it.

As for uploading a new picture, I don't know, sorry. The 'skin' of the forum you're using is one which I don't like and as such, don't use. I'm using an older skin (or an older version if you prefer). If you were using the older skin, I would have gladly told you how to do so.

BUT! You can upload to an image hosting site, such as tinypic.com, or the one I use, p1cture.me

pop000 · Jan 18, 2011, 09:09 AM

Hi. Thanks for the website I will now try to use it.

Look in the link I UPLOAD new picture, you can see there A is what I think you did in A in the blue Arrow is the mean carbon .

AND D is my try I think is not correct but tell me if I a little bit forward.

http://p1cture.me/images/42393905061930215542.jpg hope the link is OK thanks.

Unknown008 · Jan 18, 2011, 09:13 AM

Yes, the middle carbon atom is the one you pointed in blue arrow.

The picture of D you made is not really the molecule D...

Also, one tip, when you put the link, put them between [img][/ img] tags without the space I put.

For example, yours will be:

pop000 · Jan 18, 2011, 09:16 AM

Hi sorry I mean molecule C in the Right side of the carbon is need to be CH2 not CH as I showed there.
Thanks.

Unknown008 · Jan 18, 2011, 09:21 AM

Yes, okay, you also need to replace the right part by 'CH2CH3'

And yes, that's the chiral carbon atom! :)

pop000 · Jan 18, 2011, 09:25 AM

And the left side need to be COOH or just coo?
Thanks

Unknown008 · Jan 18, 2011, 09:32 AM

Oops, I misread your comment above, I thought you were referring to the part on the left. Yes, COO needs to be COOH, but in that way of writing, it's preferable to write HOOC, because it's the C which is bonded to the other C and not the O or the H.

pop000 · Jan 18, 2011, 09:35 AM

Well so I think I got it. Here is the last molecule that I think it have an Optical activity.

Is molecule E
So in the list there 3 Optical activity molecules A,C,E

Hope I correct :)
Thanks really thanks.

Unknown008 · Jan 18, 2011, 10:23 AM

Yes, it is :) Well done!

Now, we need you to answer for B and C.

pop000 · Jan 18, 2011, 12:23 PM

Well I answered on C I wrote by mistake D but I mean C .
About D is not Optical activity molecule.
And this is B

SO except D all is Optical activity molecules?

Thanks.

Unknown008 · Jan 18, 2011, 12:27 PM

Oh right.

But B is not optically active, as you can see, there are two similar groups of C2H5.

pop000 · Jan 18, 2011, 12:32 PM

Oh yes yes truth, so as I told the only optically active molecules in the my list is A,C,E yes?

Unknown008 · Jan 18, 2011, 12:35 PM

Right up to now. Now, consider D. What can you say about it?

Oh and for B, it's C2H5, not CH2H5, okay? :)

pop000 · Jan 18, 2011, 01:18 PM

Well about D I just it not have optically active is not an chiral molecule it not have a asymmetric carbon yes?
And about "B, it's C2H5, not CH2H5,"that correct my wrong.

pop000 · Jan 18, 2011, 01:29 PM

OK I upload now the last picture in this discussion ;).

I need to mark all the chiral carbon in all the molecules of this list, so in this picture I mark them in red arrow, I just need that you tell me please if I really mark all the chiral carbon.

Thanks.

DrBob1 · Jan 18, 2011, 03:16 PM

What about D? Can you see that it has TWO chiral carbon atoms?