Transition metals based metalides TM-Janus-TM (where TM=Sc–Zn and Janus=F6C6H6); A theoretical study of nonconventional metalides with excellent static and dynamic nonlinear optical properties

Abstract

Continuous progress is being made to bring forward the novel strategies for designing materials with excellent stability and exceptional nonlinear optical response. For the first time, 3d-transition series (Sc–Zn) is doped as source of excess electrons to design novel class of TM-JN-TM (TM = Sc–Zn) metalides based upon Janus-type all-cis1,2,3,4,5,6-hexafluorocyclohexane (JN) molecule. DFT calculations are performed at M06-2X/6-31+G(d,p) level of theory to explore the electronic and NLO properties of these complexes. The obtained novel metalides show excellent thermal stabilities than those of conventional alkalides and their interaction energies ranging from −3.50 to −88.33 kcal mol−1. Under the large facial polarization of JN, the valence electrons of transition metals (TM) on fluorine face serve as source of excess electron to TM metals on hydrogen face. With the excellent electronic stabilities, these complexes show significant decreased HOMO-LUMO gaps and, the performed NBO analysis also reveals their metalide character where the negative charge is observed at metal (TMH) on hydrogen face of complex C, D, G, H, and I. Among the designed metalides (TM-JN-TM), the significant first and second hyperpolarizability values of 2.43 × 106 au and 1.72 × 109 au are observed for Fe-JN-Fe complex. Simple excess electron complexes have better NLO response than that of true metalides. The observed dynamic first hyperpolarizabilities β(ω) values are much pronounced at smaller dispersion frequency (1064 nm). The frequency-dependent second hyperpolarizability γ(ω) value increased up to 5.75 × 1010 au for V-JN-V. At 1300 and 1900 nm, significant dynamic second hyperpolarizability γ(ω) values are observed. The scattering hyperpolarizability (βHRS) show significant value (2.0 × 107 au) for Fe-JN-Fe complex. We hope this work could open up new possibilities for NLO material design by using transition metals as source excess electron and, on the other hand, encourage greater experimental efforts in the laboratory to synthesize such stable compounds.