Proton transfer processes in interstellar molecular clusters under synchrotron VUV radiation: Taking acrylonitrile and acetonitrile dimers as example

•Proton transfer processes in gaseous clusters of Acrylonitrile (ALN) and acetonitrile (ATN) molecules.•Effect of conjugation and hyperconjugation.•The conjugation effect in ALN induces a high proton transfer barrier.•The hyperconjugation in the ATN molecule makes the proton transfer process a low-barrier or no-barrier process.