High‐Resolution Photoelectron Imaging of IrB3−: Observation of a π‐Aromatic B3+ Ring Coordinated to a Transition Metal

Document Type

Article

Journal/Book Title

Angewandte Chemie

Publication Date

4-25-2019

Publisher

Wiley‐VCH Verlag GmbH & Co. KGaA

Award Number

NSF, Division of Chemistry (CHE) 1664379

Funder

NSF, Division of Chemistry (CHE)

Volume

131

Issue

26

First Page

8969

Last Page

8973

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 B3 ring coordinated with the Ir atom. The isomer with the higher EA consists of a B3 ring with a bridge‐bonded Ir atom (Cs , 2A1), 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 neutral C3v isomer involves significant covalent Ir−B bonding and weak ionic bonding with charge transfer from B3 to 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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