PUB - Publikationen an der Universität Bielefeld

The synthesis, structure, and reactivity of the bicyclo[1.1.0]tetragermane‐2,4‐diide compound [(ADC)Ge ₂ ] ₂ ( 3 ), which features a Ge ₄ core bridged by two anionic dicarbene frameworks (ADC = PhC{N(Dipp)C} ₂ ; Dipp = 2,6‐iPr ₂ C ₆ H ₃ ), are reported. Treatment of an alkyne‐functionalized amidine Me ₃ SiC≡CN(Dipp)C(Ph)═N(Dipp) ( 1 ) with GeCl ₄ affords [(ADC)GeCl ₃ (GeCl ₄ )] ( 2 ). KC ₈ reduction of 2 yields 3 as a Venetian red crystalline solid. DFT calculations reveal a singlet ground state for 3 with the singlet‐triplet energy gap of 14 kcal mol ⁻¹ . CASSCF (complete active space self‐consistent field) calculations suggest a modest diradical character (β = 9%) for 3 . Compound 3 readily reacts with TEMPO (2,2,6,6‐tetramethylpiperidinyloxyl) to yield the Ge─Ge bond‐cleaved product, [(ADC)Ge(Ge‐TEMPO)] ₂ ( 4 ). Treatment of 3 with Fe ₂ (CO) ₉ gives [(ADC)Ge(Ge{Fe(CO) ₄ })] ₂ ( 5 ) .