Li doped effect of through novel noncovalent charge transfer on nonlinear optical properties

• Three complexes were designed by doping Li atom into D-S-A(1) for the first time.
• In 1-Li-Mid, intermediate cavity hinders the polarization of Li atom.
• The most negative NICS value of 1-Li-Mid is −52.0 ppm.
• The direction of crucial transition is the important factor for βtot value.
• Resonances in Li-doped D-S-A molecules resulting in huge βHRS(−2ω;ω,ω) value.

In the present work, three complexes(1-Li–NO2, 1-Li-Mid and 1-Li–NH2) were designed by doping Li atom into the different location(above, middle and below) of the novel noncovalent “through-space” electronic interaction (S) of Donor-S-Acceptor (1) to explore their structure-property relationships. The results show that doping Li atom can obviously enhance the first hyperpolarizability (βtot) of 1. Interestingly, the crucial transition direction of 1-Li–NH2 is from donor group to acceptor group, which is opposite to those of 1-Li–NO2 and 1-Li-Mid. The highest occupied molecular orbital (HOMO) of 1-Li–NH2 shows that doping one Li atom enhances the π–π interaction resulting in the largest βtot value (1.50 × 105) which is about 16 times larger than that of 1(9.13 × 103) and is also obviously larger than those of 1-Li-Mid(5.81 × 104) and 1-Li–NO2(6.45 × 104 au). The results indicate that 1-Li–NH2 can be considered as a novel high-performance NLO material and the location of Li atom can modulate NLO response.

In the present work, three complexes (1-Li–NO2, 1-Li-Mid and 1-Li–NH2) were designed by doping Li atom into the location (above, middle and below) of the S of 1 to explore their structures, aromaticities and nonlinear optical properties.Figure optionsDownload as PowerPoint slide