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Title: Transition-metal-like bonding behaviors of a boron atom in a boron-cluster boronyl complex [(η 7 -B 7 )-B-BO] −
Boron displays many unusual structural and bonding properties due to its electron deficiency. Here we show that a boron atom in a boron monoxide cluster (B 9 O − ) exhibits transition-metal-like properties. Temperature-dependent photoelectron spectroscopy provided evidence of the existence of two isomers for B 9 O − : the main isomer has an adiabatic detachment energy (ADE) of 4.19 eV and a higher energy isomer with an ADE of 3.59 eV. The global minimum of B 9 O − is found surprisingly to be an umbrella-like structure ( C 6v , 1 A 1 ) and its simulated spectrum agrees well with that of the main isomer observed. A low-lying isomer ( C s , 1 A′) consisting of a BO unit bonded to a disk-like B 8 cluster agrees well with the 3.59 eV ADE species. The unexpected umbrella-like global minimum of B 9 O − can be viewed as a central boron atom coordinated by a η 7 -B 7 ligand on one side and a BO ligand on the other side, [(η 7 -B 7 )-B-BO] − . The central B atom is found to share its valence electrons with the B 7 unit to fulfill double aromaticity, similar to that in half-sandwich [(η 7 -B 7 )-Zn-CO] − or [(η 7 -B 7 )-Fe(CO) 3 ] − transition-metal complexes. The ability of boron to form a half-sandwich complex with an aromatic ligand, a prototypical property of transition metals, brings out new metallomimetic properties of boron.  more » « less
Award ID(s):
2053541
PAR ID:
10319793
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Chemical Science
Volume:
12
Issue:
23
ISSN:
2041-6520
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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