Volume 21, Issue 21 p. 2460-2467
Article

Diborane Concatenation Leads to New Planar Boron Chemistry

Josep M. Oliva-Enrich

Corresponding Author

Josep M. Oliva-Enrich

Physical Chemistry Institute “Rocasolano”, CSIC, Serrano 119, ES-28006 Madrid, Spain

Search for more papers by this author
Takahiro Kondo

Takahiro Kondo

Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8573 Japan

Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama, 226-8503 Japan

Search for more papers by this author
Ibon Alkorta

Ibon Alkorta

Instituto de Química Médica, CSIC, Juan de la Cierva, 3, ES-28006 Madrid, Spain

Search for more papers by this author
José Elguero

José Elguero

Instituto de Química Médica, CSIC, Juan de la Cierva, 3, ES-28006 Madrid, Spain

Search for more papers by this author
Douglas J. Klein

Douglas J. Klein

Foundational Sciences, Texas A&M University at Galveston, Galveston, TX 77551 USA

Search for more papers by this author
First published: 03 August 2020
Citations: 16

Graphical Abstract

A new chapter in borane chemistry: Planar polycyclic conjugated hydrocarbons can be transformed into planar boranes by substitution of carbon atoms by boron atoms and π bonds by a perpendicular H2 moiety in the mid-point of the C=C bond, with one hydrogen atom above the boron network plane and another hydrogen atom below the boron network plane. Some singlet-triplet gaps are larger in the planar boron compound when compared to the original conjugated hydrocarbon, as in anthracene.

Abstract

Diborane has long been realized to be analogous to ethylene in terms of its bonding MOs, both as to symmetries and splitting patterns. This naturally suggests an investigation to see whether other similar conjugated hydrocarbons manifest a similar boron-substituted and H2 supplemented borane. That is, for a conjugated hydrocarbon structure with a neighbor-paired resonance pattern, we propose to look at boranes where each carbon atom is replaced by a boron atom, and an H-atom pair is added to each double bond of the resonance structure, with one H above the molecular plane and one below. This construction of concatenated diboranes is uniformly different than that for the previously known stable boranes of 4 or more B atoms. We find from quantum-chemical computations that our so constructed polyboranes are stable. All this suggests a possible novel new chapter in borane chemistry – a chapter with some promise of understandings related to that for (alternant) conjugated hydrocarbons.

Conflict of interest

The authors declare no conflict of interest.

References