Theoretical Analysis on Magnetic Properties of Conjugated Organic Molecules Containing Borepin

Theoretical study about the magnetic properties of conjugated organic molecules containing borepin with π current density was carried out. 1-(2,4,6-Trimethylphenyl)borepin moiety is the center and other different groups are situated on the both β sides, which are named molecules 1-12 as theoretical model in order to establish the relationship between aromaticity and geometry variation of borepin. The optimized molecular structures of molecules 1-12 are almost keeping planar and the C2-C3 bond length of borepin turns longer from molecule 1 to molecule 12. Different borepin-annulated ring could change the conjugated effect of π-electron between borepin and these borepin-annulated rings. Moreover, the molecule presents antiaromaticity, in other words, the molecule became unstable when the C2-C3 bond length of borepin extended more than ca. 0.1417 nm. But the β position fragment and substituent groups of borepin are not affected in this case, they are still steady. However, the central borepin ring current is counteracted by symmetrical overlap of it with affiliated borepin-annulated ring current. Hence, the central borepin ring breaking would be liable to occur. These molecules have higher vertical ionization potentials(VIPs) and lower vertical electron affinities(VEAs), which suggests that these molecules could easily exist in anionic form.