Study on the Physical Mechanism of Methylene Bridging [6]-, [8]-, and [10] Rings to Styrene under Quantum Size Effect: Spectroscopy and Aromaticity

In this study, the spectroscopic and aromaticity properties of newly synthesized methylene bridged [6], [8] and [10] rings of p-styrene (MCPP) were investigated. The photophysical properties of MCPP with n=6, 8 and 10 are calculated and analyzed by time-varying density functional theory (TD-DFT). The main characteristics of Raman spectra are revealed by vibration analysis. The results show that the contribution of π orbital to electron excitation is the main cause of antiaromaticity. By means of induced current density anisotropy (AICD), isochemical shield surface (ICSS) and magnetic induction galvanometer (GIMIC), the responses of these molecules to external magnetic fields, especially the ring current induction and magnetic shield effects, were investigated. The results show that these MCPP systems exhibit anti-aromaticity, which is mainly driven by the delocalization of strong π electrons. This study deepens the understanding of the structure and electronic properties of MCPP, and provides a reference for practical application in material design in the future.