Abstract In a high‐resolution photoelectron imaging and theoretical study of the IrB3−cluster, two isomers were observed experimentally with electron affinities (EAs) of 1.3147(8) and 1.937(4) eV. Quantum calculations revealed two nearly degenerate isomers competing for the global minimum, both with a B3ring coordinated with the Ir atom. The isomer with the higher EA consists of a B3ring with a bridge‐bonded Ir atom (Cs,2A′), and the second isomer features a tetrahedral structure (C3v,2A1). The neutral tetrahedral structure was predicted to be considerably more stable than all other isomers. Chemical bonding analysis showed that the neutralC3visomer involves significant covalent Ir−B bonding and weak ionic bonding with charge transfer from B3to Ir, and can be viewed as an Ir–(η3‐B3+) complex. This study provides the first example of a boron‐to‐metal charge‐transfer complex and evidence of a π‐aromatic B3+ring coordinated to a transition metal.
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Probing copper-boron interactions in the Cu 2 B 8 − bimetallic cluster
Borophenes are atom-thin boron layers that can be grown on coinage metal substrates and have become an important class of synthetic 2D nanomaterials. The interactions between boron and substrates are critical to understand the growth mechanisms of borophenes. Here, we report an investigation of copper-boron interactions in the Cu 2 B 8 − bimetallic cluster using photoelectron spectroscopy and quantum chemical calculations. Well-resolved photoelectron spectra are obtained at several photon energies and are combined with theoretical calculations to elucidate the structures and bonding of Cu 2 B 8 − . Global minimum searches reveal that Cu 2 B 8 − consists of a Cu 2 dimer atop a B 8 molecular wheel with a long Cu–Cu bond length close to that in Cu 2 + . Chemical bonding analyses indicate that there is clear charge transfer from Cu 2 to B 8 , and the Cu 2 B 8 − cluster can be viewed as a [Cu 2 + ]-borozene complex, [Cu 2 + ][B 8 2– ]. In the neutral cluster, no Cu–Cu bond exists and Cu 2 B 8 consists of two Cu + centers interacting with doubly aromatic B 8 2− borozene. The charge transfer interactions between Cu and boron in the Cu 2 B 8 − cluster are analogous to charge transfer from the copper substrate to the first borophene layer recently reported to be critical in the growth of bilayer borophenes on a Cu(111) substrate.
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- Award ID(s):
- 2053541
- PAR ID:
- 10402313
- Date Published:
- Journal Name:
- Journal of Vacuum Science & Technology A
- Volume:
- 40
- Issue:
- 4
- ISSN:
- 0734-2101
- Page Range / eLocation ID:
- 042201
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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