Alkali and Transition Metal-Doped 15-Crown-5 with Enhanced Nonlinear Optical Response: A DFT Study

Abstract

In this study, geometries, electronic structure and first hyperpolarizability of metals doped 15-crown-5 (C5M) were explored through the density functional theory (DFT) method. Alkali metals (Li, Na, K) and silver (Ag) were placed inside and outside of the crown ether, respectively, to deliver three compounds designated as Li[C5M]Ag, Na[C5M]Ag and K[C5M]Ag. All designed complexes were optimized at singlet, triplet, quintet and septet states, where the singlet state was identified as the stable state. The influence of doping on C5M can be investigated by energy gap fluctuation and it was noted that the smallest energy gap (4.68[Formula: see text]eV) was exhibited by K[C5M]Ag among all the intentional complexes, in contrast to reference C5M (12.73[Formula: see text]eV). Moreover, the density of state (DOS), transition density matrix (TDM), noncovalent interaction (NCI), molecular electrostatic potential (MESP) and electron density distribution map (EDDM) analysis were implemented. Static isotropic polarizability values were observed in the range of [Formula: see text]–[Formula: see text] esu which were comparable to dynamic isotropic polarizability values; [Formula: see text]–[Formula: see text]. Li[C5M]Ag revealed maximum first hyperpolarizability ([Formula: see text]) of [Formula: see text][Formula: see text]esu with the minimum transition energy ([Formula: see text]) of 2.93[Formula: see text]eV.