Highly strained tricyclic molecules: tricyclo[p.q.0.01,f]alkanes and phosphatricyclo[m.1.0.01,3]alkanes

We theoretically investigate ring strains of tricyclic molecules or tricyclo[p.q.0.01,f]alkanes by calculating the strain energies as heat of the homodesmotic reactions. The strain energies are well correlated with the deformation from the tetrahedral configuration of the C1 atom. We theoretically design less strained tricyclic molecules by replacing some carbon atoms with phosphorus atoms.