organic chemistry reactivity of carbon dioxide

It’s important to remember that every curly arrow must start at a pair of electrons, either in a bond, or a lone pair on an atom. We will be in essence extending this concept here but now, the electrons will be moving in such a way as to create or destroy bonds. The resonance structures involved electrons jumping around at thousands of times the rate that the atoms themselves could move, so it was just simpler to assume the atoms don’t move.

We have explored this concept earlier when we looked at resonance structures of a single molecule or polyatomic ion species. Remember that the electrons are thousands of times lighter than the nuclei of the atoms themselves so although we often think and speak as if it’s the atoms that do the moving, we are better off to imagine the electrons as doing the moving while the atoms are relatively motionless. To keep track of these changes, we use curly arrows to represent the movement of electrons. Many reactions take several steps to occur and each step may involve the creation or destruction of bonds. Generally, we can write an overall process as a simple balanced chemical reaction, but that reaction often does not happen in a single step as is implied by the single equation. When we draw out the reaction mechanisms, it’s important to keep track of where the electrons are, especially the ones involved in forming and breaking bonds. For example, a carbon-carbon double bond has two pairs of electrons in close proximity to each other, making for a concentration of negative charge whereas, if there is an electronegative atom bonded to a carbon, it will tend to inductively withdraw some of the electron density away from the carbon creating a positive charge concentration on that carbon. The charges in the substrate (the main organic molecule being reacted) will occur depending on the structure composition of the molecule. Chemical reactions in organic compounds tend to occur at reactive sites on the molecules, where there is buildup of either positive or negative charge.

Organic chemistry reactivity of carbon dioxide