2-Germaazulene: Synthesis and Properties of 2-Heteraazulene Containing a Germanium Atom as a Skeletal Element

Abstract

We have succeeded in the synthesis of a 2-germaazulene stable in solution, in which the carbon atom at the 2-position of azulene is replaced by a germanium atom, the fourth period element in Group 14. The properties of the obtained 2-germaazulene were verified both experimentally and theoretically, indicating its sufficient aromaticity. In comparison with the parent azulene, significant differences were found in its orbital levels, charge distribution, and the resulting properties.