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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.
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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 AcidLewis 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-AlCl3 Lewis 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 The N formal charge changes from 0 to +1. Therefore, it is donating electrons. An arrow must start at N.
Example 3 The O formal charge changes from 0 to -1. Therefore, it is accepting electrons. An arrow must end at O.
Example 3 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 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 The nitrogen containing compound is the species that is donating electrons. Therefore, it is the Lewis Base.
Example 3 Lewis Base The oxygen containing compound is the species accepting the electrons. Therefore, it is the Lewis Acid.
Example 3 Lewis AcidLewis Base