“…Thus, it is clear that the low-bias conductance of molecules 1−3 is mainly determined by LUMO, and the decrease of the energy level of LUMO from molecule 1 to molecule 3 improves the alignment of the frontier molecular orbitals relative to the Fermi energy of the electrodes to enhance the conductance. 11,35 However, according to previous theoretical studies 36,37 and the reported conductance enhancement, which are all about 0.3 order with the dominated energy levels changing less than 1 eV, 11,12,35,38−40 the energy shift of about 0.7 eV from molecule 1 to molecule 3 alone cannot afford the conductance enhancement of about 1.5 orders of magnitude. Thus, the coupling between the molecule and the electrodes, which is another crucial parameter in Landauer's theory to determine the conductance, 36,41 was analyzed to explore the origin of conductance enhancement.…”