Abstract
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).