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    Quinoidal Azaacenes: 99 % Diradical Character
    (Weinheim : Wiley-VCH Verlag, 2020) Intorp, S.N.; Hodecker, M.; Müller, M.; Tverskoy, O.; Rosenkranz, M.; Dmitrieva, E.; Popov, A.A.; Rominger, F.; Freudenberg, J.; Dreuw, A.; Bunz, U.H.F.
    Quinoidal azaacenes with almost pure diradical character (y=0.95 to y=0.99) were synthesized. All compounds exhibit paramagnetic behavior investigated by EPR and NMR spectroscopy, and SQUID measurements, revealing thermally populated triplet states with an extremely low-energy gap ΔEST′ of 0.58 to 1.0 kcal mol−1. The species are persistent in solution (half-life≈14–21 h) and in the solid state they are stable for weeks.
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    Salts of HCN-Cyanide Aggregates : [CN(HCN)2]− and [CN(HCN)3]−
    (Weinheim : Wiley-VCH, 2020) Bläsing, Kevin; Harloff, Jörg; Schulz, Axel; Stoffers, Alrik; Stoer, Philip; Villinger, Alexander
    Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN−), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph4P, Ph3PNPPh3=PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN)2]− and trihydrogen tetracyanide ions [CN(HCN)3]− from liquid HCN when a fast crystallization was carried out at low temperatures. X-ray structure elucidation revealed hydrogen-bridged linear [CN(HCN)2]− and Y-shaped [CN(HCN)3]− molecular ions in the crystal. Both anions can be considered members of highly labile cyanide-HCN solvates of the type [CN(HCN)n]− (n=1, 2, 3 …) as well as formal polypseudohalide ions. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.