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The two-electron reduction of a Group 14-element(I) complex [RË⋅] (E=Ge, R=supporting ligand) to form a novel low-valent dianion radical with the composition [RË:]. 2− is reported. The reaction of [LGeCl] ( 1, L=2,6-(CHNAr)2C6H3, Ar=2,6- iPr2C6H3) with excess calcium in THF at room temperature afforded the germylidenediide dianion radical complex [LGe]. 2−⋅Ca(THF)32+ ( 2). The reaction proceeds through the formation of the germanium(I) radical [LGe⋅], which then undergoes a two-electron reduction with calcium to form 2. EPR spectroscopy, X-ray crystallography, and theoretical studies show that the germanium center in 2 has two lone pairs of electrons and the radical is delocalized over the germanium-containing heterocycle. In contrast, the magnesium derivative of the germylidendiide dianion radical is unstable and undergoes dimerization with concurrent dearomatization to form the germylidenide anion complex [C6H3-2-{C(H)NAr}Ge-Mg-6-{C(H)-NAr}]2 ( 3). [ABSTRACT FROM AUTHOR]

The syntheses and structures of heteroleptic germanium(II) and tin(II) chlorides supported by anionic ligands derived from 2,3-dimethyl-1,4-diaza-1,3-butadiene are described. The reaction of ArN=C(Me)C(Me)=NAr ( L, Ar = 2,6- iPr2C6H3) with MeLi in Et2O, followed by treatment with GeCl2 ·dioxane or SnCl2, afforded [ L1ECl] [ L1 = ArN=C(Me)C(Me)2NAr; E = Ge ( 1), Sn ( 2)]. Moreover, L2Li [ L2 = ArN=C(Me)C(=CH2)NAr] reacted with GeCl2 ·dioxane in Et2O to form [{C(=CH)NAr}{C(Me)=NAr}]2(GeCl)2 ( 3). The byproducts are [{C(CH2)NAr}{C(Me)=NAr}Ge]2 ( 4) and L2H ( 5). Furthermore, the reaction of L with LiN iPr2 in Et2O, followed by treatment with SnCl2, afforded [ L2SnCl] ( 6). Compounds 1- 4 and 6 have been characterized by NMR spectroscopy and X-ray crystallography. [ABSTRACT FROM AUTHOR]