Lewis Acids, Lewis Bases, and Curvy Arrows
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Lewis Acids, Lewis Bases, and Curvy Arrows Susan F. Hornbuckle Associate Professor of Chemistry Clayton State University
description
Lewis Acids, Lewis Bases, and Curvy Arrows. Susan F. Hornbuckle Associate Professor of Chemistry Clayton State University. Example 1. CH 3 -CH 2 -Br + - OH CH 3 -CH 2 -OH + Br - The Br formal charge changes from 0 to -1. Therefore, it is accepting electrons. - PowerPoint PPT Presentation
Transcript of Lewis Acids, Lewis Bases, and Curvy Arrows
Lewis Acids, Lewis Bases, and Curvy Arrows
Susan F. Hornbuckle
Associate Professor of Chemistry
Clayton State University
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH + Br-
The Br formal charge changes from 0 to -1. Therefore, it is accepting electrons.
An arrow must end at the Br.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH + Br-
The O formal charge changes from -1 to 0. Therefore, it is donating electrons. An arrow must be starting at O.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH +
Br-
A bond is formed between O and C. The arrow starting at O must end at the C where it bonds.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH +
Br-
A bond is broken between Br and C. The arrow that ends at Br must start at the bond between Br and C.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH +
Br-
-OH is the species that is donating electrons. Therefore, it is the Lewis Base.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH + Br-
Lewis Base
The bromoethane is the species accepting the electrons. Therefore, it is the Lewis Acid.
Example 1
CH3-CH2-Br + -OH CH3-CH2-OH +
Br-
Lewis Acid Lewis Base
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3
The Cl formal charge changes from 0 to +1. Therefore, it is donating electrons. An arrow must start at Cl.
+ -
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3
The Al formal charge changes from 0 to -1. Therefore, it is accepting electrons. An arrow must end at Al.
+ -
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3
A bond is formed between Al and Cl. Therefore, the arrow starting at Cl must end at Al.
+ -
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3
The chloroethane is the species that is donating electrons. Therefore, it is the Lewis Base.
+ -
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3Lewis Base
AlCl3 is the species accepting the electrons. Therefore, it is the Lewis Acid.
+ -
Example 2
CH3-CH2-Cl + AlCl3 CH3-CH2-Cl-AlCl3 Lewis Base Lewis Acid
+ -
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
The N formal charge changes from 0 to +1. Therefore, it is donating electrons. An arrow must start at N.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
The O formal charge changes from 0 to -1. Therefore, it is accepting electrons. An arrow must end at O.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
A bond is broken between C and O. The arrow that ends at O must start at the bond between C and O.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
A bond is formed between N and C. The arrow that starts at N must end at the C where it forms a bond.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
The nitrogen containing compound is the species that is donating electrons. Therefore, it is the Lewis Base.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
Lewis Base
The oxygen containing compound is the species accepting the electrons. Therefore, it is the Lewis Acid.
Example 3
CH3
C
CH3
O
+ N
CH3
CH3CH3
O
C CH3CH3
N CH3CH3
CH3
-
+
Lewis Acid Lewis Base
