Divalent germanium compound with a radical-anionic ligand:: Molecular structures of (dpp-BIAN)•-GeCl and its hydrochloration products [(dpp-BIAN)(H)2]•+[GeCl3]- and [{(dpp-BIAN)(H)2•+}2(Cl-)]+[GeCl3]- (dpp-BIAN=1,2-bis{(2,6-diisopropylphenyl)imino}acenaphthene)

The germanium(II) compound (dpp-BIAN)GeCl (1), which contains the radical anion of dpp-BIAN can be prepared either by reacting free dpp-BIAN ligand with 2 equiv of GeCl2(1,4-dioxane) in Et2O or by metathetical reaction of the sodium salt of dpp-BIAN with germanium dichloride in Et2O or benzene. The reaction of benzene solutions of 1 with 2 or 3 equiv of HCl led to protonation of the dpp-BIAN ligand affording [(dpp-BIAN)(H)(2)](.+)[GeCl3](-) (2) and [{(dpp-BIAN)(H)(2)(.+)}(2)(Cl-)](+)[GeCl3](-) (3), which incorporate the radical cation of the protonated ligand. Compounds 1-3 have been characterized by elemental analysis, IR, UV-vis, and electron spin resonance (ESR) spectroscopy. Molecular structures of 1-3 were determined by single-crystal X-ray diffraction. In molecule 1, the Ge atom is positioned at the apex of the slightly distorted trigonal pyramid. The Ge-N bond lengths in 1 are 2.0058(19) and 2.004(2) Angstrom. The molecular structure of 2 consists of contact ions [(dpp-BIAN)(H)(2)](+) and [GeCl3](-). In the molecular structure of 3, two radical cations of [(dpp-BIAN)(H)(2)](+) are coordinated by the chlorine anion. The ESR signal of 1 indicates the presence of a dpp-BIAN radical anion and shows a hyperfine structure due to the coupling of an unpaired electron to N-14, Ge-73, Cl-35, Cl-37, and H-1 nuclei (A(N) = 0.48 (2 N), A(Ge) = 0.96, A(Cl) = 0.78 (Cl-35), A(Cl) = 0.65 (Cl-37), A(H) = 0.11 (4 H) mT, g = 2.0014). Both 2 and 3 reveal ESR signals of radical cation [(dpp-BIAN)(H)(2)](.+) (septet, A(N) = 0.53, A(H) = 0.48 mT, g = 2.0031).