TY  - JOUR
A1  - Saalfrank, Christian
A1  - Fantuzzi, Felipe
A1  - Kupfer, Thomas
A1  - Ritschel, Benedikt
A1  - Hammond, Kai
A1  - Krummenacher, Ivo
A1  - Bertermann, Rüdiger
A1  - Wirthensohn, Raphael
A1  - Finze, Maik
A1  - Schmid, Paul
A1  - Engel, Volker
A1  - Engels, Bernd
A1  - Braunschweig, Holger
T1  - cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States
JF  - Angewandte Chemie International Edition
N2  - Narrow HOMO–LUMO gaps and high charge‐carrier mobilities make larger acenes potentially high‐efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open‐shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO–LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10‐diboraanthracenes, which are shown to feature disjointed, open‐shell singlet biradical ground states.
KW  - acenes
KW  - biradicals
KW  - bond Activation
KW  - boron
KW  - heterocycles
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217795
VL  - 59
IS  - 43
SP  - 19338
EP  - 19343
ER  - 
TY  - JOUR
A1  - Hermann, Alexander
A1  - Fantuzzi, Felipe
A1  - Arrowsmith, Merle
A1  - Zorn, Theresa
A1  - Krummenacher, Ivo
A1  - Ritschel, Benedikt
A1  - Radacki, Krzysztof
A1  - Engels, Bernd
A1  - Braunschweig, Holger
T1  - Oxidation, Coordination, and Nickel-Mediated Deconstruction of a Highly Electron-Rich Diboron Analogue of 1,3,5-Hexatriene
JF  - Angewandte Chemie, International Edition
N2  - The reductive coupling of an N-heterocyclic carbene (NHC) stabilized (dibromo)vinylborane yields a 1,2-divinyl- diborene, which, although isoelectronic to a 1,3,5-triene, displays no extended p conjugation because of twisting of the C\(_2\)B\(_2\)C\(_2\) chain. While this divinyldiborene coordinates to copper(I) and platinum(0) in an η\(^2\)-B\(_2\) and η\(^4\)-C\(_2\)B\(_2\) fashion, respectively, it undergoes a complex rearrangement to an η\(^4\)-1,3-diborete upon complexation with nickel(0).
KW  - boron
KW  - diborenes
KW  - carbenes
KW  - conjugation
KW  - density-functional calculations
KW  - rearrangements
KW  - structure elucidation
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240652
VL  - 59
IS  - 36
ER  -