Presentation of Molecules

Presentation of Molecules refers to different ways of representing molecular structures, such as Fischer, Newman, Sawhorse, and wedge-dash projections.

Presentation of Molecules

1. Wedge-Dash (3D) Projection

   • Purpose:

     • Shows the actual 3D spatial orientation of atoms or groups.

   • Features:

     • Solid wedge (▲): Bond coming out of the plane (towards you)
     • Dashed wedge (▿ or dashed line): Bond going behind the plane
     • Straight lines: Bonds in the plane of the paper/screen

   • Example:

   • 

2. Fischer Projection

   • Purpose:

     • Common for sugars and amino acids
     • Good for comparing D/L configurations

   • Rules:

     • Vertical bonds: Go behind the plane
     • Horizontal bonds: Come out toward the viewer
   • 

Steps to Convert Wedge-Dash to Fischer Projection

1. Identify the chiral center

   • The central carbon is bonded to four different groups.

2. Orient the molecule correctly

   • Make sure the horizontal bonds in the Fischer projection represent groups coming out of the plane (wedges).
   • The vertical bonds represent groups going into the plane (dashes or behind the plane).

3. Rearrange the molecule

   • Rotate the wedge-dash structure so that:
     • The two groups on wedges (or wedge and regular line) are left and right (horizontal)
     • The two groups on dashes/behind or straight lines are top and bottom (vertical)

4. Draw the Fischer projection

   • Vertical line = bonds going into the plane (back)
   • Horizontal line = bonds coming out of the plane (toward you)
   • Place the correct groups based on their positions

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!