Isolation of an Annulated 1,4-Distibabenzene Diradicaloid |
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| Authors: | Henric Steffenfauseweh Dr. Dennis Rottschäfer Dr. Yury V. Vishnevskiy Beate Neumann Dr. Hans-Georg Stammler Dr. Dariusz W. Szczepanik Priv.-Doz. Dr. Rajendra S. Ghadwal |
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| Affiliation: | 1. Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany;2. Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland |
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| Abstract: | The first 1,4-distibabenzene-1,4-diide compound [(ADC)Sb]2 ( 5 ) based on an anionic dicarbene (ADC) (ADC=PhC{N(Dipp)C}2, Dipp=2,6-iPr2C6H3) is reported as a bordeaux-red solid. Compound 5 , featuring a central six-membered C4Sb2 ring with formally SbI atoms may be regarded as a base-stabilized cyclic bis-stibinidene in which each of the Sb atoms bears two lone-pairs of electrons. 5 undergoes 2 e-oxidation with Ph3C[B(C6F5)4] to afford [(ADC)Sb]2[B(C6F5)4]2 ( 6 ) as a brick-red solid. Each of the Sb atoms of 6 has an unpaired electron and a lone-pair. The broken-symmetry open-shell singlet diradical solution for ( 6 )2+ is calculated to be 2.13 kcal mol−1 more stable than the closed-shell singlet. The diradical character of ( 6 )2+ according to SS-CASSCF (state-specific complete active space self-consistent field) and UHF (unrestricted Hartree-Fock) methods amounts to 36 % and 39 %, respectively. Treatments of 6 with (PhE)2 yield [(ADC)Sb(EPh)]2[B(C6F5)4]2 ( 7 -E) (E=S or Se). Reaction of 5 with (cod)Mo(CO)4 affords [(ADC)Sb]2Mo(CO)4 ( 8 ). |
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| Keywords: | Antimony Aromaticity Carbene Diradicaloid Heterocycle |
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