Structural Calculation And Theoretical Study On Bonding Properties Of Bimetallic Doped Boron Clusters

Electron-deficient property of boron allows boron clusters to be easily doped by multi-electron metals in order to balance the electron distribution and maintain stability.Each metal exhibits various properties of the system in terms of geometric configuration,electronic structure and bonding characteristics in a different doping mode.On this basis,the structures of different bimetallic（transition metal and main group metal）boron clusters were systematically studied in paper.Thermodynamic stability was verified by using the random search configuration（ABcluster）program.The electronic structure of the system was understood in detail through a variety of bond analysis methods,and the photoelectron spectrum of the system was simulated to study its potential application in metal-doped boron materials.The main contents and conclusions of the study are as follows:Ⅰ.Theoretical study of transition metal doped boron cluster M₂B₈^-/0（M=Sc,Y）Transition metal dope boron clusters have been obtain in many systems with interesting electronic and structural properties.we have found that the global minimum of M₂B₈^-/0（M=Sc,Y）is the anti-intercalation complex.Due to the Jahn-Teller effect,the M₂B₈^-anion has D_4hsymmetry,while the neutral M₂B₈ complex produces perfect D_8h symmetry.There is a strong chemical bond between the M atom and the 2s and 2p orbitals of the B₈ ring.All d orbitals of the M₂ dimer completely overlap and the three d_π/σorbitals of the M₂B₈ complex mix perpendicularly with the three delocalizedσorbitals on the boron ring,resulting in a less pronounced M…M interaction.Due to the strong interaction of the（d-p）δbond and the additional electrostatic stabilization,the formation of a highly stable anti-sandwich structure is driven.II.Theoretical Study of Bi-Doped Boron Clusters in Group VBismuth is considered to be a"green metal"due to its low toxicity,which has attracted more and more attention in chemistry and material science.In this chapter,a series of Bi-doped boron clusters Bi₂B_n^-（n=10,11）have been studied by using theoretical calculations and simulated photoelectron spectra.The globally most stable structure of Bi₂B₁₀^- is a perfect plane composed of a B₁₀ wheel and two Bi atoms bonded to its edge,which has dual aromaticity.The global minimum of Bi₂B₁₁^- is a semi-sandwich structure,in which a B₁₁ unit and a Bi atom are bonded to the edge,and another Bi atom is vertically inserted into the B₁₁ ring and coordinated with it,thus possessing double anti-aromaticity.The bonding analysis showed that the Bi atom interacted with the planar boron atom through its three 6p orbitals by covalent bonds to form two Bi-Bσbonds,which were 6p_x and 6p_y orbitals,respectively,while the 6p_z orbital participated in the formation of the delocalizedπbond.Therefore,when the doped metal is the transition metal M=（Sc,Y）,the anti-sandwich structure is more likely to be formed,and the"non-classical M-M bond"is generated.B_n ring with larger size（n=10,11）and the main group bimetallic Bi show different properties after doping.Bi₂B_n^-prefers to form perfect planar structure and semi-sandwich structure.