Inorganic Chemistry, Vol.51, No.2, 1002-1010, 2012
Reactivity of Digermylenes toward Potassium Graphite: Synthesis and Characterization of Germylidenide Anions
The synthesis and characterization of the digermylenes [LGe-GeL] [L = L-1 (3A), L-2 (3B)] supported by the 2,6-diiminophenyl (L-1) and 2-imino-5,6-methylenedioxylphenyl (L-2) ligands are described. Their reactivities toward potassium graphite are also reported. The reaction of [LGeCl] [L = L-1 (2A), L-2 with (2B)] KC8 in tetrahydrofuran (THF) at room temperature afforded the digermylenes [LGe-GeL] [L = L-1 (3A), L-2 (3B)], which are the first examples of diaryldigermylenes stabilized by o-imino donor(s). The treatment of 3A with 2 equiv of KC8 in Et2O, followed by the addition of excess tetramethylethylenediamine (TMEDA), results in cleavage of the Ge-I-Ge-I bond to afford the germylidenide anion [(LGeK)-Ge-1.TMEDA] (4A). Similarly, the reaction of 3B with excess KC8 in THF afforded the germylidenide anion [(LGeK)-Ge-2] (4B). The molecular structures of compounds 4A and 4B as determined by single-crystal X-ray diffraction analysis show that the K atoms are eta(1)-coordinated with the low-valent Ge atoms. Moreover, the negative charges at the Ge atoms in compounds 4A and 4B are stabilized by electron delocalization in the germanium heterocycles.