All Questions
Tagged with optical-properties stereochemistry
36
questions
14
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1
answer
8k
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Maximum observed optical rotation through a polarimeter
Is there a maximum optical rotation of plane polarized light that can be observed using a polarimeter?
I understand that in a polarimeter, light passes through a filter that converts it into plane ...
- 2,545
11
votes
1
answer
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Are there chiral compounds that don't rotate plane-polarized light?
I know that meso compounds have chiral centers but don't rotate plane-polarized light, and I know that there can be non-traditionally chiral compounds (e.g. ones with large substituents that prohibit ...
- 213
10
votes
1
answer
2k
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How is plane polarized light rotated by chiral compounds? [duplicate]
There are plenty of questions related to this topic on this site but no proper answer.
Can anyone please explain to me how plane polarized light is rotated by chiral compounds, and why it cannot be ...
- 177
9
votes
2
answers
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Why do only chiral molecules rotate the plane of polarized light and how do they rotate it?
I have learnt that only chiral or unsymmetrical molecules can rotate the plane of linearly polarized light. But, why is it so?
And how can molecules rotate the plane or what does it actually mean by ...
- 3,345
8
votes
2
answers
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Does inversion of configuration necessitate reversed optical rotation?
Say, optically pure 2-bromobutane undergoes $\mathrm{S_N2}$ reaction with an alkali to form 2-butanol. The configuration about chiral carbon will now be inverted, but is it necessary that the sign of ...
- 365
8
votes
1
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What are chiral environments?
I keep seeing the term cropping up, but cannot seem to find a definition for it. My understanding is that it is an environment in which, when the isomers interact with the environment, the two ...
- 1,697
8
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1
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Why are complexes of type MA3B3 not optical active?
Complexes of type $\ce{MA3B3}$ have two geometrical isomers, namely:
fac-isomer
mer-isomer
If we look closely at the mer-isomer, it has a plane of symmetry, so it is optically inactive.
But the fac-...
- 111
7
votes
1
answer
2k
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What is there in this 3D representation of organic molecules I fail to grasp?
I think there's a basic idea I'm missing about 3 Dimensional representation of molecules. I think it may be about converting to Fischer representation. Consider the following two products of ...
- 217
7
votes
0
answers
373
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What compound has the strongest optical rotation of polarised light?
A question recently asked here whether compounds know to be chiral can have non-measurable optical rotations: Are there chiral compounds that don't rotate plane-polarized light?.
Apparently they ...
- 37k
6
votes
2
answers
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Is tetraammine dichloro cobalt (III) an optically active compound?
Is
$$ \text{Co}[{(\text{N}{\text{H}}_{3})}_{4}{\text{Cl}}_{2}]$$
optically active? If so, write its stereo-isomers.
I know that for a compound to be optically active, it should rotate the plane of ...
- 443
6
votes
1
answer
2k
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Are a meso compound and its mirror image isomers?
How are meso isomers even isomers? By definition, meso isomers are compounds that are superposable on their mirror images, but doesn't that mean that the mirror image is just the same compound?
Can ...
- 1,161
4
votes
1
answer
426
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Does syn-dihydroxylation form racemic mixture?
I have been asked to determine the nature of the product for the following reaction:
And as I recognized this reaction to be a case of syn-dihydroxylation, my obvious response was that the product ...
- 462
4
votes
2
answers
824
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Can a system of 2 consecutive biphenyl systems be optically active , even if any adjacent biphenyl systems aren't optically active?
This question came in an online test, where they asked whether or not 22,26-dibromo-12,32-dichloro-23,25-diiodo-16,36-dimethyl-11,21:24,31-terphenyl was optically active.
The answer is that, it is ...
- 247
4
votes
0
answers
52
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Is optical activity of a given compound a statistical picture?
When optical activity is taught it is done in terms of single molecules. But when it is actually measured it is done on a large collection of such molecules. So, how does the asymmetry manifest itself ...
- 470
3
votes
1
answer
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Finding chiral carbons in aromatic or cyclic compounds
I know that for a carbon to be chiral four different groups should be attached to that particular carbon. But, what about in the case of cyclic compounds? What's the method to check chirality if the ...
- 3,345
3
votes
1
answer
813
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Would Z and E isomers show different optical activity?
Consider this compound, which is in E-configuration and that red asterisk denotes the chiral carbon. If I were to somehow cause the E-configuration of the alkene part to Z-configuration keeping the ...
- 484
3
votes
2
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197
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Chirality and Optical activity
Do all chiral objects rotate the plane of polarization of EM waves? For example my hand is chiral, will it rotate the plane of polarization of EM waves of suitable wavelength?
user102687
3
votes
0
answers
75
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Does optical isomerism fall under the category of stereoisomerism?
I have been asked to find the total number of dichlorination products (including stereoisomers) for the following reaction:
I have figured out nine possible structures out of which two are optically ...
- 462
2
votes
1
answer
633
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How does Entropy influence the racemization of an optically active compound?
We were doing the topic "Isomerism" in our Organic Chem class and there's a question in our worksheet whose answer I haven't really understood, the question is as follows:
The racemization ...
- 133
2
votes
1
answer
840
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How many stereoisomers can exist for 4,5-bis(3-hydroxyoct-1-en-1-yl)cyclopentane-1,3-diol?
Q.10 For the given compound $\ce{X}$, the total number of optically active stereoisomers is ____.
This is from JEE Advanced 2018 second question paper.
I thought the answer to be at least 32 because ...
- 754
2
votes
1
answer
2k
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How do we identify left handed and right handed crystals?
I was going through this article about how Louis Pasteur studied and explained the absence of optical activity in Racemic acid. Here's an extract:
When Pasteur next examined crystals of the same
...
- 1,091
1
vote
1
answer
232
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Doubt in chirality and pseudo chirality
So a carbon atom is chiral if it has 4 different group attached to it, and it is pseudo chiral if it has 3 different groups of atoms attached to it, where the 2 similar groups have different ...
- 169
1
vote
1
answer
48
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When to permute two times to find optical configuration [closed]
I'm learning about S and R configuration, and I know that in case where the 4th substituant is not behind we should permute it with the one which is behind. then we find the new configuration and use ...
- 21
1
vote
2
answers
8k
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Can diastereomers form a racemic mixture?
In my book, it says racemic mixture is the mixture of + and - optical isomers and it is optically inactive. This means enantiomers (optical isomers which are mirror images to each other) can form ...
- 131
0
votes
2
answers
5k
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Meso and achiral does both term means the same?
When a molecule has plane of symmetry, or centre of symmetry it is termed as an achiral compound (though it contain some chiral centres). Same goes for the meso compounds due to the internal ...
- 754
0
votes
2
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72
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Optical activity of (1r,3R,5S)-3,5-dimethyl-4-methylidenecyclohexan-1-ol
Could anyone explain why compound L is not optically active?
- 21
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votes
1
answer
2k
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Which are the Geometrical isomers of the complex [Cr(NH3)2Cl2(en)]+?Is it one or two?
I was recently studying coordination compounds and i came across optical isomerism shown by complexes.I think that the complex i gave above have 4 geometrical isomers(I think this is where I am wrong, ...
0
votes
1
answer
223
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Which of the following isomers of 2,3‐dihydroxy‐4‐methoxy‐4‐oxobutanoic acid are identical?
Which of the following are identical?
A and B are identical
A and B are diastereomers
A and C are enantiomers
A and B are enantiomers
What I know is that when we rotate a Fisher projection by 180°, ...
- 371
0
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0
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1k
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What are the limitations of the D, L system and the (+), (-) system for naming organic compounds
In organic chemistry, both the D, L system and the (+), (-) system are widely used, in conjunction with the modern (R, S) system.
The D, L system names an organic molecule based on the direction that ...
- 99
0
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0
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525
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Are centre of symmetry(COS) and alternate axis of symmetry(AAOS) dependent on each other?
COS=Centre of symmetery
AAOS=Alternate axis of symmetry
Lets suppose a molecule has a COS. Does it need to have AAOS?
What about the converse? If a molecule has AAOS does it necessarily have a COS?
...
