For question relating to isomers which cause plane polarized light to be rotated in opposite directions.

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1answer
37 views

Determining chirality after considering conformational interconversion in a cyclohexane

Basically I want to know what does the question mean when it says "taking into consideration conformational interconversions." I assume it means, when I draw the mirror image of the given compound, ...
3
votes
1answer
123 views

Defining enantiomer of morphine by R/S designation

How to know if the following chemical structure of morphine is an R or S? What I basically need to know is: which chirality center do we use to make the decision? $\hskip2in$
4
votes
1answer
65 views

Why is 2-chloropropene achiral?

Could someone explain to me why some alkenes containing at least one couple of different substituents at the two double-bonded C atoms (that is, some of those with at least two different substituents ...
5
votes
1answer
119 views

Can molten sugar also rotate polarized light as sugar water does?

It is well know that the sugar water can rotate the plane of linearly polarized light, so light bends when travelling in sugar water. However, do the liquid state of sugar but not the sugar solution ...
10
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1answer
85 views

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 ...
3
votes
1answer
45 views

State of a Racemic Mixture

Is a racemic mixture always an equi-molar solution of two enantiomers, both in the same state? Is it necessary for both isomers to be in the liquid state for racemisation to occur, or does ...
13
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3answers
223 views

How to assign E/Z configuration according to the Cahn-Ingold-Prelog rules when subsituents differ only by stereochemistry

I stumbled-upon this compound: CC=C1C(C)CCC1(C) I'm wondering how to determine the configuration of the double bond. Is it E or Z? How do I decide on the ...
2
votes
1answer
47 views

Configurations of Reactants in Second Order Nucleophilic Substitutions

The question asks me to draw the product for the reactions. However, I am stuck and do not understand how to draw the reactants with configurations correctly. (a) (S)-2-Chloropentane and NaSH I ...
3
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3answers
61 views

Chirality Centers

The compound below is fexofenadine and the only chirality center, as identified by the textbook is, the one circled in red. I do not understand why the carbon attached to the O by a double bond and ...
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4answers
250 views

How to identify a compound as chiral or achiral

I read my book and learned everything about enantiomers, racemization, $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions, but when I'm trying to identify molecules as chiral or achiral, I get confused. ...
3
votes
1answer
55 views

Stereochemistry: R and S notation

How do we number the carbon atoms in symmetrical molecules while giving R and S notation. For instance, in 2,3-Dibromobutane, there is an ambiguity over which is carbon C2 and carbon C3. Will we call ...
2
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1answer
24 views

Chirality, physical or chemical property

Heyo, I was wondering whether one would consider chirality a physical or chemical property. In my opinion it should be both, because it will affect the way in which plane polarized light is interacted ...
2
votes
1answer
59 views

Can pseudochirality be considered when 3 or 4 groups on the C atom are the same?

When for example the C atom is bonded to one H, and then three more structurally identical groups with 2 chiral C each - in configurations R,R and S,S and R,S respectively - then by assigning each of ...
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0answers
42 views

Chirality vs Resonance in chemical structure

In a reference book, chirality of a molecule is explained as "handedness", like our right and left hand, which are mirror images of each other. These are also called as enantiomers. The nearest clue ...
2
votes
2answers
256 views

Chirality on Propranolol

I'm a bit confused when asked to specify the chiral carbons on this sketch of Propranolol as I'm not sure how the $\ce{H3C}$ and $\ce{CH3}$ play in if they are reversed in the name like that...Does ...
2
votes
2answers
37 views

Is there anything akin to molecular chirality for crystalline?

For example, in hexagonal closed-packed (HCP) structure, the atoms may be arranged in ABAB stacks or ACAC stacks. Can these two be considered enantiomers? Do they possess different solid state ...
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vote
2answers
747 views

Are all amino acids except glycine chiral compounds?

Specifically, I was thinking of the case where the R group is a carboxylic acid functional group or an amine group. Then there would not be a chiral carbon atom. Is there a restriction on what can be ...
3
votes
1answer
50 views

Is bicyclo[1.1.0]butane chiral?

Is bicyclo[1.1.0]butane chiral? I think it isn't, but if one of the hydrogen atoms bound to the tertiary or secondary carbon atoms is replaced with e.g. chlorine, the formed compound will be chiral, ...
2
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4answers
91 views

Gas phase chiral molecules

Are there any molecules that are chiral that are also gases at room temperature? Failing that, what chiral molecules have a high vapor pressure? Propylene oxide has a boiling point of only 34 C, so ...
4
votes
3answers
232 views

How can I determine the number of possible pairs of diastereomers?

How can I determine the number of possible pairs of diastereomers here? Here was the question: "How many pairs of diastereomers are possible in the following molecule? PhCH(Cl)CH(Ph)CH(Cl)Ph" I ...
3
votes
3answers
728 views

Concept of “non-superimposable mirror image” in chirality

I didn't understand the fact that chiral objects are non-superimposable on their mirror images. I mean, if you put your right hand (apparently an achiral object) in front of a mirror, the mirror image ...
0
votes
1answer
87 views

What are some of the simplest chiral molecules in biological systems

I have understood generally for a while there is a significant preference in "life" for so-called "left-handed" (chiral) molecules, though I'm reading things now that say "life" sugars are ...
2
votes
1answer
110 views

Are Grignards Chiral?

Can Grignards be chiral? I've seen them drawn as ionic structures in class. I've also seen little asterisks on certain positions of Grignards (a common designation of chirality). So this begs the ...
3
votes
1answer
147 views

Assign the configurations of the stereo centres in (-)-menthol and (+)-neomenthol?

I have to assign R or S to the chiral centers in (-)-menthol and (+)-neomenthol. The results I got are shown below in the picture. However, when I looked on Wikipedia to check my answers they ...
3
votes
1answer
155 views

Simple experiments involving enantiomer synthesis

I want to do an experiment to investigate factors affecting the synthesis of chiral molecules. The only problem is, my institution doesn't have much money, and it seems like the chemicals required for ...
5
votes
1answer
691 views

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 ...
0
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2answers
85 views

Chirality of heteroatoms

Why is a phosphorus atom with three different substituents chiral, but nitrogen isn't? Nitrogen inverts fast, while phosphorus obviously much slower. How is that explained?
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2answers
195 views

Isopropyl and Butyl Groups - Relative Priorities

This does not compute for me: Why would the four-carbon butyl group have a lower relative priority than the 3 carbon isopropyl group? If we compare the carbons one by one between the isopropyl and ...
0
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1answer
78 views

How to Rotate Chiral Carbon

I know that to correctly assign R,S priorities I have to rotate the above figure until the H is projecting into the page (away from me). However, I don't know how to rotate the H and the rest of the ...
0
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2answers
33 views

Does the Arrangement of Atoms Matter Around Chiral Carbon?

In other words, are these two structures equivalent?
0
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1answer
22 views

Configuration, chirality

I'm having trouble assigning priorities for this molecule: I tried assigning priorities with the rules for doubly bonded atoms in mind. I know that the lowest priority group should be going into the ...
0
votes
1answer
357 views

Drawing (R)-1,1,2-trimethylcyclohexane

I tried drawing out (R)-1,1,2-trimethylcyclohexane but I can't seem to figure it out. I think I"m getting hung on assigning priorities. I've labeled the chiral carbon with an asterisk. I've also ...
0
votes
3answers
103 views

what is the simple enantiomer in the powder form that one can get?

I want to do some experiments on enantiomers. As it involves more calculations of potential energy surfaces, I would like to do this experiment on a simple enantiomer. For example CHBrClF. But this is ...
2
votes
2answers
2k views

Why are allenes chiral?

How is this molecule chiral? $(Br)HC=C=CH(Cl)$ My thoughts: I know that chiral carbons have different groups attached to it. Here the end carbons have two different groups and a double bond. But, ...
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1answer
97 views

Liquid crystal current flow

In a liquid crystal cell used for LCD the conductive substrates, usually made of ITO, are in contact with the liquid crystal. The question is: when a voltage is applied to the electrodes to reorient ...
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vote
2answers
847 views

Why only chiral molecules rotate plane polarized light and how does it rotate light?

I have learnt that only chiral or unsymmetrical molecules can rotate plane polarized light. But, why is it so? And how can molecules rotate plane polarized light or what does it actually mean by ...
5
votes
1answer
355 views

Molecular chirality and optical rotation

Why does having molecular chirality result in optical rotation? The dissymetry or chirality of molecules translates to the rotation of plane polarized light, the magnitude and direction depending on ...
2
votes
1answer
184 views

Racemization of biphenyl compounds

How does the effect of heat and effect of substituents affect racemization of biphenyl compounds?
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0answers
57 views

How would you change the chirality of a compound such that (S,R) becomes (S,S)? [closed]

How would you change the chirality of a compound such that (S,R) becomes (S,S)? That is how would you synthesise a compound from its diastereomer?
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1answer
1k views

If I have a chiral substrate, should I always assume that both enantiomers are present?

Considering the Sn1 reaction of (S)-2,3-dimethyl-3-pentanol, knowing that this molecule has a chiral carbon, should I always assume that both enantiomers are present, and therefore the products of a ...
7
votes
1answer
11k views

What does the “D” group represent on a chiral center?

I am trying to figure out the configuration for this chiral carbon to answer a homework question, however they arbitrarily include a "D" group as shown in the image. My guess is that it is some higher ...
11
votes
2answers
257 views

Is there a simple way to get the circular dichroism of a molecule from it's structure?

Are there any heuristics to get the relative absorbtion of left and right circularly polarized light by a molecule from its molecular structure? Is it even possible to predict which polarization is ...