- #1
Which Materials Have Optical Activity?
Click For Summary
Discussion Overview
The discussion revolves around identifying which materials possess optical activity, focusing on the role of chiral molecules in this property. Participants explore definitions, characteristics of chirality, and specific examples from a provided list of molecules.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- One participant inquires about which materials from their list exhibit optical activity, noting the requirement of chiral molecules.
- Another participant seeks clarification on the definition of a chiral molecule and encourages application of this definition to specific examples.
- A definition of chiral molecules is provided, emphasizing the lack of internal symmetry and the presence of asymmetric carbon atoms.
- Participants discuss the criteria for chirality, specifically the necessity of having four different substituents on a carbon atom.
- One participant attempts to identify chiral molecules from their list, suggesting that certain molecules (A, C, E) may be chiral based on their structure.
- Questions arise regarding the chirality of carbon atoms involved in double bonds and the number of substituents they possess.
- Clarifications are made about the definition of substituents and their implications for determining chirality.
- One participant confirms their understanding that molecules A, C, and E are optically active, while another notes that chiral substances can have multiple chiral carbons.
- There is a question about whether molecule D contains more than one chiral carbon.
Areas of Agreement / Disagreement
Participants generally agree on the definition of chiral molecules and the criteria for chirality, but there is ongoing discussion about specific examples and the presence of multiple chiral centers in certain molecules. The discussion remains unresolved regarding the complete identification of all optically active materials from the list.
Contextual Notes
Some participants express uncertainty about the implications of double bonds on chirality and the exact number of substituents on specific carbon atoms, which may affect the conclusions drawn about optical activity.
- #2
Borek
Mentor
- 29,204
- 4,626
What is a definition of chiral molecule? Can you try to apply definition to these molecules?
- #3
omni
- 192
- 1
well A chiral molecule is a type of molecule that lacks an internal plane of symmetry and has a non-superposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom.
i know that activity Optical is possible only in chiral molecules.
can you show me one molecule from my list then i can try to deduce from it.
thank you.
i know that activity Optical is possible only in chiral molecules.
can you show me one molecule from my list then i can try to deduce from it.
thank you.
- #4
Borek
Mentor
- 29,204
- 4,626
Chiral molecules have (at least) one asymmetric carbon. That means carbon with four different substituents. Take a look at your molecules, count different groups attached to each carbon - if there is four, you have a chiral molecule.
http://en.wikipedia.org/wiki/Chirality_(chemistry)
http://en.wikipedia.org/wiki/Chirality_(chemistry)
- #5
omni
- 192
- 1
ok i think i start to understand,
so if i correct the Chiral molecules in my list is A,C,E in my picture here is hard to see but the carbon atom in molecules c have an covalent bond with hydrogen in the left side.
the rule "Chiral molecules have (at least) one asymmetric carbon. That means carbon with four different substituents" is also acceptable when there an double covalent bond like we have here when the carbon atoms have an double covalent bond with hydrogen atoms?
thank you.
so if i correct the Chiral molecules in my list is A,C,E in my picture here is hard to see but the carbon atom in molecules c have an covalent bond with hydrogen in the left side.
the rule "Chiral molecules have (at least) one asymmetric carbon. That means carbon with four different substituents" is also acceptable when there an double covalent bond like we have here when the carbon atoms have an double covalent bond with hydrogen atoms?
thank you.
- #6
Borek
Mentor
- 29,204
- 4,626
How many substituents in the carbon with a double bond?
- #7
omni
- 192
- 1
well there 1 substituents in the carbon with a double bond Because the double bond are connection with 1 atoms.
look in the new picture i mark in blue the different substituents Including the atom O that i think he have double bond with the asymmetric carbon.
as you can see E and A is almost the same.
thank you.
look in the new picture i mark in blue the different substituents Including the atom O that i think he have double bond with the asymmetric carbon.
as you can see E and A is almost the same.
thank you.
Attachments
- #8
omni
- 192
- 1
"a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon"
- #9
Borek
Mentor
- 29,204
- 4,626
OK, I will put it differently. You have a carbon with a double bond. Is it possible that it has four substituents? Take a look at the picture you have just attached - to how many atoms/groups of atoms is the carbon bonded? Four?
- #10
omni
- 192
- 1
no only to Three atoms/groups of atoms (CH,O,OH)
really thank you.
really thank you.
- #11
omni
- 192
- 1
hi. i found that molecules A,C,E are activity Optical that is correct ?
thanks.
thanks.
- #12
Borek
Mentor
- 29,204
- 4,626
You are correct so far, but it is not a full answer.
Chiral substance may have more than one chiral carbon.
Chiral substance may have more than one chiral carbon.
- #13
omni
- 192
- 1
D have than one chiral carbon yes?
thanks
thanks
Similar threads
Chemistry
Structural formulas & optical activity
- · Replies 1 ·
Chemistry
Coordination chemistry problem
- · Replies 5 ·
- · Replies 10 ·
- · Replies 3 ·
- · Replies 3 ·
- · Replies 2 ·
- · Replies 5 ·
- · Replies 6 ·