Superalkali atoms bonding to the phenalenyl radical: structures, intermolecular interaction and nonlinear optical properties.

Due to unpaired electrons, both radicals and superalkali are investigated widely. In this work, two interesting complexes (Li3O-PLY and Li3-PLY) were constructed by phenalenyl radical and superalkali atoms. Why are they interesting? Firstly, for Li3O-PLY and Li3-PLY, although the charge transfer between superalkali atoms and PLY is similar, the sandwich-like charge distribution for Li3O-PLY causes a smaller dipole moment than that of Li3-PLY. Secondly, their UV-vis absorption show that the maximum wavelengths for Li3O-PLY and Li3-PLY display a bathochromic shift compared to PLY. Moreover, Li3-PLY has two new peaks at 482 and 633 nm. Significantly, the β 0 values of Li3-PLY (4943-5691 a.u.) are much larger than that of Li3O-PLY (225-347 a.u.). Further, the β HRS values of Li3O-PLY decrease slightly while β HRS of Li3-PLY increase dramatically with increasing frequency. It is our expectation that these results might provide beneficial information for theoretical and experimental studies on complexes with superalkali and PLY radicals. Graphical Abstract Two interesting complexes (Li3O-PLY and Li3-PLY) were constructed by phenalenyl radical and superalkali atoms. We explore their structures, Wiberg bond indices, interaction energies and the static first hyperpolarizabilities (β 0). The β 0 values of Li3-PLY (4943-5691 a.u.) were much larger than those of Li3O-PLY (225-347 a.u.).