Formation of the MB Teetotum Boron Clusters with 4d and 5d Transition Metals M = Rh, Pd, Ir, and Pt.

In the present theoretical study using DFT computations, we successfully designed a series of boron clusters possessing a teetotum shape stabilized upon metal doping. The resulting MB teetotum geometry emerges as a general structural motif for the B boron cluster doped by either two 4 and 5 transition metal atoms. Doping of two different metal atoms also conserves the teetotum motif such as in the mixed RhPdB and IrPtB clusters. A bonding analysis points out that each dimeric metal unit enjoys several stabilizing orbital interactions with an idealized B tubular moiety and thereby establish a bimetallic configuration of [σ(σ-B)] [π(π-B)] [σ(σ-B)] [δ(δ-B)] [σ*(σ-B)] [π*] [σ(σ*-B)] [δ*] for 4d metals and of [σ(σ-B)] [π(π-B)] [σ(σ-B)] [δ(δ-B)] [σ*(σ-B)] [π*] [σ(σ*-B)] [δ*] for 5d metal atoms for 24 electrons. All the MB teetotum structures considered behave as aromatic compounds whose character is indicated by the strongly diatropic current density.