1449240-92-9Relevant articles and documents
Acyclic germylones: Congeners of allenes with a central germanium atom
Li, Yan,Mondal, Kartik Chandra,Roesky, Herbert W.,Zhu, Hongping,Stollberg, Peter,Herbst-Irmer, Regine,Stalke, Dietmar,Andrada, Diego M.
, p. 12422 - 12428 (2013)
The cyclic alkyl(amino) carbene (cAAC:)-stabilized acyclic germylones (Me2-cAAC:)2Ge (1) and (Cy2-cAAC:) 2Ge (2) were prepared utilizing a one-pot synthesis of GeCl 2(dioxane), cAAC:, and KC8 in a 1:2:2.1 molar ratio. Dark green crystals of compounds 1 and 2 were produced in 75 and 70% yields, respectively. The reported methods for the preparation of the corresponding silicon compounds turned out to be not applicable in the case of germanium. The single-crystal X-ray structures of 1 and 2 feature the C-Ge-C bent backbone, which possesses a three-center two-electron π-bond system. Compounds 1 and 2 are the first acyclic germylones containing each one germanium atom and two cAAC: molecules. EPR measurements on compounds 1 and 2 confirmed the singlet spin ground state. DFT calculations on 1/2 revealed that the singlet ground state is more stable by ～16 to 18 kcal mol-1 than that of the triplet state. First and second proton affinity values were theoretically calculated to be of 265.8 (1)/267.1 (2) and 180.4 (1)/183.8 (2) kcal mol -1, respectively. Further calculations, which were performed at different levels suggest a singlet diradicaloid character of 1 and 2. The TD-DFT calculations exhibit an absorption band at ～655 nm in n-hexane solution that originates from the diradicaloid character of germylones 1 and 2.
