title: All-boron analogues of aromatic hydrocarbons: B17- and B18-.
abstract: We have investigated the structural and electronic properties of the B(17)(-) and B(18)(-) clusters using photoelectron spectroscopy (PES) and ab initio calculations. The adiabatic electron detachment energies of B(17)(-) and B(18)(-) are measured to be 4.23 ± 0.02 and 3.53 ± 0.05 eV, respectively. Calculated electron detachment energies are compared with experimental data, confirming the presence of one planar C(2v) ((1)A(1)) isomer for B(17)(-) and two nearly isoenergetic quasi-planar C(3v) ((2)A(1)) and C(s) ((2)A') isomers for B(18)(-). The stability and planarity/quasi-planarity of B(17)(-) and B(18)(-) are ascribed to σ- and π-aromaticity. Chemical bonding analyses reveal that the nature of π-bonding in B(17)(-) and B(18)(-) is similar to that in the recently elucidated B(16)(2-) and B(19)(-) clusters, respectively. The planar B(17)(-) cluster can be considered as an all-boron analogue of naphthalene, whereas the π-bonding in the quasi-planar B(18)(-) is reminiscent of that in coronene.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, Utah 84322-0300, USA.
authors.forename: Alina P
authors.initials: AP
authors.lastname: Sergeeva
authors.forename: Boris B
authors.initials: BB
authors.lastname: Averkiev
authors.forename: Hua-Jin
authors.initials: HJ
authors.lastname: Zhai
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Boldyrev
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang