Modular Approach to Kekulé Diradicaloids Derived from Cyclic (Alkyl)(amino)carbenes

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Hansmann MM, Melaimi M, Munz D, Bertrand G
Zeitschrift: Journal of the American Chemical Society
Jahr der Veröffentlichung: 2018
Band: 140
Heftnummer: 7
Seitenbereich: 2546 - 2554
ISSN: 1520-5126


Abstract

A modular approach for the synthesis of Kekulé diradicaloids is
reported. The key step is the insertion of a carbene, namely, a cyclic
(alkyl)(amino)carbene (CAAC), into the C-H bonds of two terminal alkynes
linked by a spacer. Subsequent hydride abstraction, followed by
two-electron reduction of the corresponding bis(iminium) salts, affords
the desired diradicaloids. This synthetic route readily allows for the
installation of communicating spacers, featuring different degrees of
aromaticity and lengths, and gives the possibility of generating
unsymmetrical compounds with two different CAACs. Electron paramagnetic
resonance (EPR), NMR, UV-vis, and X-ray studies in combination with
quantum-chemical calculations give insight into the electronic nature of
the deeply colored Kekulé diradicaloids. They feature a singlet ground
state with varying degrees of diradical character in combination with
small singlet/triplet gaps. Upon lengthening of the spacer, the
properties of the compounds approach those of monoradicals in which
steric protection of the propargyl radical moiety is necessary to
inhibit decomposition pathways. Most of these diradicaloids are stable
at room temperature, both in solution and in the solid state, but are
highly oxygen-sensitive. They represent the first diradicaloids derived
from iminium salts.


FAU-Autoren / FAU-Herausgeber

Munz, Dominik Dr. rer. nat.
Lehrstuhl für Anorganische und Allgemeine Chemie


Zitierweisen

APA:
Hansmann, M.M., Melaimi, M., Munz, D., & Bertrand, G. (2018). Modular Approach to Kekulé Diradicaloids Derived from Cyclic (Alkyl)(amino)carbenes. Journal of the American Chemical Society, 140(7), 2546 - 2554.

MLA:
Hansmann, M. M., et al. "Modular Approach to Kekulé Diradicaloids Derived from Cyclic (Alkyl)(amino)carbenes." Journal of the American Chemical Society 140.7 (2018): 2546 - 2554.

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Zuletzt aktualisiert 2019-07-02 um 10:08