A bimetallic 1,1’-bis(boratabenzene) complex: unprecedented intramolecular metal-metal communication through a B-B bond

Braunschweig, Holger, Demeshko, Serhiy, Ewing, William C, Krummenacher, Ivo, Macha, Bret B, Mattock, James D, Meyer, Franc, Mies, Jan, Schäfer, Marius and Vargas, Alfredo (2016) A bimetallic 1,1’-bis(boratabenzene) complex: unprecedented intramolecular metal-metal communication through a B-B bond. Angewandte Chemie International Edition, 55 (27). pp. 7708-7711. ISSN 1521-3773

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Abstract

We report the synthesis of the first 1,1’-bis (boratabenzene) species by tetrabromodiborane(4) induced ring-expansion reactions of cobaltocene. Six equivalents of cobaltocene are required as the species plays the dual role of reagent as well as reductant to yield [{(η5-C5H5)Co}2{μ:η6,η6-(BC5H5)2}]. X-ray crystallographic analysis shows that the compound consists of coplanar BC5H5 rings which are coordinated on opposite faces to two cyclopentadienyl cobalt moieties, resulting in a trans-configured bimetallic complex. The formally dianionic bis(boratabenzene) moiety with a boron-boron single bond can be viewed as a symmetric dimer of the parent boratabenzene anion as well as the first example of a diboron analogue of biphenyl. The solution electrochemistry of the bimetallic complex shows four stepwise redox events, indicating significant intramolecular interaction between the cobalt ions across the 1,1’-bis(boratabenzene) unit. The magnetic properties, as investigated by variable-temperature SQUID magnetometry, reveal weak intramolecular antiferromagnetic interactions (J = −6.0 cm−1). Density Functional Theory calculations support the experimental results and add insights into the various electronic states of the complex.

Item Type: Article
Schools and Departments: School of Life Sciences > Chemistry
Subjects: Q Science > QD Chemistry
Depositing User: Alfredo Vargas
Date Deposited: 06 Jun 2016 09:17
Last Modified: 09 Jun 2017 21:39
URI: http://sro.sussex.ac.uk/id/eprint/60768

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