文摘
Effect of terminal substituents on self-assembly behavior of porphyrin molecules has been studied with three derivatives modified with distinctly different substituents, 5,15-(di-3,5-di-tert-butylphenyl) porphyrin, 5,15-(dimesityl) porphyrin, and 5,15-(di-4-ethynylphenyl) porphyrin. Scanning tunneling microscopy and density functional calculations reveal that 5,15-(di-3,5-di-tert-butylphenyl) porphyrin, 5,15-(dimesityl) porphyrin, and 5,15-(di-4-ethynylphenyl) porphyrin spontaneously give different ordered structures on Ag(110) surface both at room temperature and after annealing. It is clear that the tert-butylphenyl substituent could increase the intermolecular van der Waals interactions to form stable network structure under condition of thermal activation, whereas the mesityl substituent plays an essential role in the formation of rigid chain structure as a result of the CH–π interactions between the mesityl groups of molecule enantiomers. Moreover, the ethynylphenyl substituent could induce metal atoms to coordinate with ethynyl to form organometallic chains. Copyright
