title: Cyclic boron clusters enclosing planar hypercoordinate cobalt, iron, and nickel.
abstract: Planar cyclic boron clusters with cobalt, iron, and nickel atoms at their centerssinglet D(8h) CoB(8)(-), D(9h) FeB(9)(-), CoB(9), and NiB(9)(+)are computed to be stable minima at the BP86/TZVPP DFT level. Stochastic searches of the singlet and triplet potential energy surfaces show the planar hypercoordinate D(8h) CoB(8)(-) (1) and D(9h) FeB(9)(-) (2) singlet isomers to be the global minima. Their double aromatic character with 6 pi and 10 radial electrons is documented by detailed NICS(zz) grid and CMO-NICS(zz) analyses at PW91/TZVPP. These results encourage gas phase investigations of these two exotic anions. Although isoelectronic with D(9h) FeB(9)(-) (2), CoB(9) and NiB(9)(+) prefer nonplanar structures, triplet 3-aT for the former and singlet 4-a for the latter.
authors.affiliation: Department of Chemistry, Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Keigo
authors.initials: K
authors.lastname: Ito
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Pu
authors.forename: Qian-Shu
authors.initials: QS
authors.lastname: Li
authors.forename: Paul von Ragué
authors.initials: Pv
authors.lastname: Schleyer