Aryl Germanes as Ligands for Transition Polymetallic Complexes: Synthesis, Structure, and Properties

A series of new carbonyl dichromium complexes bearing aryl germanes as ligands were prepared using improved approaches. The thermal reaction of Cr(CO)₆ (1) with Me₃GeGePh₃ (3) led to the formation of Me₃GeGePh[(η⁶‐C₆H₅)Cr(CO)₃]₂ (3a). The lithiation of [(η⁶‐C₆H₆)Cr(CO)₃] (2) with nBuLi followed by the addition of Me₂GeCl₂ (4) or ClGeMe₂GeMe₂Cl (5) gave Me₂Ge[(η⁶‐C₆H₅)Cr(CO)₃]₂ (4a) and [(OC)₃Cr(η⁶‐C₆H₅)]GeMe₂GeMe₂[(η⁶‐C₆H₅)Cr(CO)₃] (5a), respectively. The molecular structures of 3a and 4a, in their crystal forms, were studied by X‐ray diffraction analysis. The crystals of oligogermane 3a have shown to undergo a fully reversible phase transition at 160 K without any sign of decomposition. The complexes synthesized were also studied by multinuclear NMR, IR and UV/Vis spectroscopy, DFT calculations and electrochemistry. The presence of a Cr(CO)₃ group in a range of oligogermanes has shown to impact on the physical and chemical properties of the compounds.