In this work, a detailed theoretical investigation of the substituent groups effect on the geometric and electronic properties of the newly proposed molecular wire has been performed with the DFT-B3LYP/6-31G* level of theory by considering the influence from the external electric field (EF). The results show that the performance of molecular wire is very sensitive to the electron donating (–NH2 and –OH), electron withdrawing (–NO2 and –F) groups and external EF intensities. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), ELUMO–EHOMO (HLG) in all cases decreased, furthermore, the electron withdrawing –NO2 group had a much lower HLG than the other substituted groups. Results of this study indicate that the substitutions and external electric field can be used to tune the properties of a molecular scale device effectively.
