Figure 3.

Effect of dispersion forces and conformation on reactivity. a) Computational investigations of the reaction between 4a, 4b, 5a, and 5b with the model isonitrile methyl isocyanide. Energies are shown in kcal mol⁻¹. Labels at the structures indicate the atomic contribution to the intermolecular dispersion interaction. Contributions of hydrogens were summed into corresponding carbon atoms. The label above the ring structure denotes the sum of interaction for all six tetrazine atoms. b) Introducing phenyl groups into the tetrazine substituents enhances reactivity toward isonitriles (DMSO: PBS, 4:1, pH = 7.4, T = 25 °C, PhEtNC), likely by locking the bromo groups into a gauche conformation.