Final Answer:
The atoms participating in 1,3-diaxial interactions in the shown conformation of cis-1,2-dimethylcyclohexane are the two axial hydrogens on C-1 and C-3. There is a total of two 1,3-diaxial interactions in this molecule.
Step-by-step explanation:
In cis-1,2-dimethylcyclohexane, the methyl groups are on the same face, resulting in one axial methyl group. To identify the atoms involved in 1,3-diaxial interactions, we look at the axial positions. In the given conformation, C-1 has an axial hydrogen (H-1_ax) pointing up, and C-3 also has an axial hydrogen (H-3_ax) pointing down. These hydrogens are 1,3-diaxial to each other.
To calculate the total number of 1,3-diaxial interactions, we count how many pairs of 1,3-diaxial interactions are present. In this case, there is one pair, involving H-1_ax and H-3_ax. Therefore, the total number of 1,3-diaxial interactions is two, as each interaction involves two atoms.
Understanding 1,3-diaxial interactions is crucial in the context of cyclohexane conformations, as they contribute to the overall stability of the molecule. Minimizing these interactions is favorable for a more energetically stable conformation. In this specific case, the presence of two 1,3-diaxial interactions highlights the steric strain associated with the axial substituents in cis-1,2-dimethylcyclohexane.