Tuning Electronic Structure and Optical Properties of Li@cyclo[18]carbon Complex via Switching Doping Position of Lithium Atom

Abstract

Doping alkali metal atoms, especially lithium (Li), in nanocarbon materials has always been considered as one of the most effective methods to improve the optical properties of the system. In this theoretical work, we doped a Li atom into the recently observed all-carboatomic molecule, cyclo[18]carbon (C<sub>18</sub>), and finally obtained two stable configurations with Li inside and outside the ring. The calculation results show that the energy barrier of transition between the two Li@C<sub>18</sub> complexes is quite low, and thus the conversion is easy to occur at ambient temperature. Importantly, the electronic structure, absorption spectrum, and optical nonlinearity of the two configurations are found to be significantly different, which indicates that the electronic structure and optical properties of the Li@C<sub>18</sub> complex can be effectively regulated by switching the location of the doped Li atom between inside and outside the carbon ring. With the help of a variety of wave function analysis techniques, the nature of the discrepancies in the properties of the Li@C<sub>18</sub> complex with different configurations has been revealed in depth. The relevant results of this work are expected to provide theoretical guidance for the future development of cyclocarbon-based optical molecular switches.

Metal-centered monocyclic carbon wheel clusters with record coordination numbers in planar species

“…Very recently, the electronic properties of metal-carbon ring complexes such as Li@C 18 and MC 16 have been reported. 10,11 Carbon ([He]2s 2 2p 2 ) is known to be effective ligand to various transition metals with a smaller covalent radius than boron ([He]2s 2 2p 1 ), while group IIIB metals La, Y, and Sc with the valence electronic congurations of (n-1)d 1 ns 2 possess the largest covalent radii in the periodic table. 12 Metal-centered monocyclic carbon wheel clusters M©C n k+ (M ¼ La, Y, Sc) are thus possible to have even higher coordination numbers than their boron counterparts M©B n kÀ .…”

Origin of structure and stability of M@C18 (M = Cu, Ag, and Au) complexes with D9h point group

“…One of these complexes is metal atom encage in the centroid of C 18 ring (in the present work we refer it as endohedral complex) and other is exohedral complex. 22 Further, it is interesting to observe from the same study that the electronic and optical properties of the Li@C 18 complex can be efficiently controlled by switching the position of the doped lithium atom between the endo and exohedrally. 22 Feasibility of encapsulating the magnesium dimer inside the C 18 ring was also evaluated using a density functional theory (DFT) calculations.…”

“…22 Further, it is interesting to observe from the same study that the electronic and optical properties of the Li@C 18 complex can be efficiently controlled by switching the position of the doped lithium atom between the endo and exohedrally. 22 Feasibility of encapsulating the magnesium dimer inside the C 18 ring was also evaluated using a density functional theory (DFT) calculations. 23 The results revealed that the endohedral structure of Mg 2 @C 18 is aromatic and stabilizes in the form of Mg 2+ [C18] 2À .…”

“…16 The majority of these studies focused on the noncovalent interactions (NCI). 14,17,[22][23][24][25]43 The newly synthesized C 18 molecule has the potential to trap the atoms, ions and molecules to form the complexes owing to the presence of a significant size pore with small negative electrostatic potential. It is worth to mention that computational studies by Liu and colleagues have created momentous interest among the theoretical community to unravel the chemistry of C 18 and its associated complexes.…”

“…It is worth to mention that computational studies by Liu and colleagues have created momentous interest among the theoretical community to unravel the chemistry of C 18 and its associated complexes. 7,8,14,16,22,[32][33][34] However, the detailed experimental studies of these class of complex is in its infancy. Herein, we describe some of the important contributions from computational investigations on the C 18 and its complexes.…”