PUB - Publikationen an der Universität Bielefeld

The first 1,4-distibinine-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 Sb(I) 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 2e-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 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 39% and 36%, 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]2-Mo(CO)4 (8). © 2023 Wiley-VCH GmbH.