Classify the following molecules into chiral o achiral HO H? H? H? H? Br ????? ???? ??? OH NH2 9. Draw an enantiomer of each of the following molecule: H2N HO H SH 10. Draw a diastereomer of each of the following molecule: Br F Br NH2 CI Br NH2 OH HO HO
The Correct Answer and Explanation is:
Let’s break this down into two main tasks: classification of chirality and the drawing of enantiomers and diastereomers.
8. Classification of Chiral vs Achiral Molecules
A molecule is chiral if it has a non-superimposable mirror image, meaning it lacks a plane of symmetry. An achiral molecule has a plane of symmetry and is superimposable on its mirror image.
- HO – Without more context, this is ambiguous as a single hydroxyl group attached to a molecule does not define chirality on its own.
- H2 – A molecule with only hydrogen atoms can’t be classified as chiral unless part of a more complex structure.
- Br – Similarly, the presence of a single bromine atom doesn’t indicate chirality unless part of a chiral center.
- OH, NH2 – Hydroxyl and amino groups may contribute to chirality if they are part of a molecule with a chiral center. For example, if an asymmetric carbon is bonded to these groups, it may be chiral.
To provide specific classifications for each molecule, I would need their full structures and the number of substituents around each carbon. However, it’s safe to assume that molecules with multiple substituents that are non-identical (like Br, OH, NH2) on a single carbon could be chiral.
9. Enantiomer Drawing
Enantiomers are pairs of molecules that are non-superimposable mirror images of each other. They occur when a molecule has a chiral center.
Let’s break down the provided molecule:
- H2N HO H SH
This seems to be a molecule with multiple groups attached to a central carbon, such as an amino group (H2N), hydroxyl group (OH), hydrogen (H), and thiol group (SH).
To draw an enantiomer:
- Switch the position of any two groups attached to the chiral center.
- If we swap the hydrogen (H) and the thiol group (SH), the molecule becomes the enantiomer.
10. Diastereomer Drawing
Diastereomers are stereoisomers that are not mirror images of each other. They have different physical properties, unlike enantiomers, which have identical physical properties except for their interaction with plane-polarized light.
Here’s the provided molecule:
- Br F Br NH2 CI Br NH2 OH HO HO
This molecule has multiple chiral centers (indicated by the presence of different substituents on different carbons). To create a diastereomer, you would modify the configuration at one or more but not all of the chiral centers. This would lead to a molecule with a different 3D arrangement of atoms, but not a mirror image.
For example, if you flip the configuration at one of the chiral centers, while leaving the others unchanged, you get a diastereomer.
In summary:
- Chiral vs. achiral depends on whether the molecule has a chiral center (usually a carbon bonded to four different groups).
- Enantiomers are mirror-image molecules, while diastereomers are non-mirror-image stereoisomers.
