Structures, stabilities and spectral properties of metalloborospherenes MB400/- (M = Cu, Ag, and Au)

The discovery of borospherene B-40 marks the onset of a new class of boron fullerenes and it is of current interest in chemical physics and, in particular, boron chemistry. In this work, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are carried out to study the structures, stabilities, photoelectron spectra, infrared spectra, Raman spectra and electronic absorption spectra of metalloborospherenes MB400/- (M = Cu, Ag, and Au). It is found that Cu, Ag and Au atoms can form stable exohedral metalloborospherenes M&B-40(0/-) (M = Cu, Ag, and Au) and endohedral metalloborospherenes M@B-40(0/-) (M = Cu, Ag, and Au). In addition, the relative energies of these metalloborospherenes suggest that Cu, Ag and Au atoms favor the exohedral configuration. The Cu atom favors an exohedral geometry with the dopant face-capping a heptagon on the side surface (eta 7-Cu), whereas Ag and Au atoms favor exohedral geometries with the dopant bonding a side boron atom of the hexagonal ring. The calculated spectra suggest that doping of metal atoms in borospherene B-40 can change the spectral features since the extra metal atoms can modify the electronic structure of borospherene B-40. The addition of metal atoms can lead to more infrared and Raman active modes and redshift the electronic absorption spectra. The calculated results also show that metalloborospherenes MB400/- (M = Cu, Ag, and Au) have different and meaningful spectral features, insight into the spectral properties is important to understand the compounds and reveal their potential applications. These spectral features can be readily compared with future spectroscopy measurements and used as fingerprints to identify and distinguish the metalloborospherenes MB400/- (M = Cu, Ag, and Au).