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.

Experimental and computational evidence of octa- and nona-coordinated planar iron-doped boron clusters: Fe©B8− and Fe©B9−

“…3b) was identified in the work by Ito et al in stochastic searches of both singlet and triplet potential energy surfaces of FeB 9 À [40]. All other structures were found to lie higher in energy [40].…”

“…À was already established as the global minimum of FeB 9 À in a previous theoretical report [40], we ran an extensive global minimum search only for FeB 8 À . The search was conducted using the Coalescence Kick method [49] and the UPBE0 [50,51]/ LANL2DZ [52] level of theory.…”

“…Prior to this study there were no experimental reports on any Fe-doped boron clusters and there are only a few computational reports on wheel-type clusters. The most relevant works [40,41] investigated the electronic structures and geometries of a number of metal-centered boron clusters using global minimum search and DFT calculations. These studies showed that in the ground state FeB 9 À is aromatic and has a D 9h symmetry and that the D 8h -FeÓB 8 2À wheel structure is also the global minimum on the FeB 8 2À potential energy surface.…”

MB 8 2− (M = Be, Mg, Ca, Sr, and Ba): Planar octacoordinate alkaline earth metal atoms enclosed by boron rings

“…Very recently, planar hypercoordinate transition metals, e.g., Fe, Co, Ni, Au, Sc and Zn have also been investigated [35][36][37][38][39][40][41][42]. A systematic study of planar hypercoordinate molecules with first row d-block metal atoms in the center of boron rings was carried out in our earlier computational work [43,44]. Many species with D nh (n = 7 to 10) symmetry were obtained and D 8h CoB 8  , D 9h FeB 9  , and D 8h FeB 8 2 were…”

B19−: ein aromatischer Wankel‐Motor

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Huang et al entdeckten vor kurzem die energetisch stabilste Struktur von B 19À (1): eine Radstruktur, bestehend aus zwei ineinandergeschachtelten ebenen aromatischen p-Systemen.[ In den letzten zehn Jahren wurden mithilfe der Computerchemie mehrere radförmige Borstrukturen vorgeschlagen, die Hauptgruppenelement- [8][9][10][11][12][13][14] oder Übergangsmetallato-me [15][16][17][18]

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