The series of oligogermanes Pr i 3 Ge-(GePh 2 ) n GePr i 3 (n = 0, 2; n = 1, 3; n = 2, 4; n = 3, 5) were prepared by the hydrogermolysis reaction. All four species were characterized by NMR ( 1 H and 13 C) and UV/visible spectroscopy as well by cyclic voltammetry and differential pulse voltammetry. The oligogermanes exhibited a successive red shift in their absorbance maxima as the length of the Ge−Ge chain was increased, and these molecules also became easier to oxidize as the chain length was increased. The X-ray crystal structures of 4 and 5 as well as the trigermane HPh 2 GeGePh 2 GePh 2 H (6) were determined. The pentagermane 5 was shown to be dichroic in the solid state due to the packing of the individual molecules in a columnar fashion in the crystal. Pentagermane 5 is also luminescent in solution, exhibiting an emission maximum at 380 nm. The physical properties of 5, like the hexagermane Pr i 3 Ge(GePh) 4 GePr i 3 , mimic the properties of the larger polygermane systems.

The oligogermane nBu 3 GeGePh 2 GenBu 3 was photolyzed using UV-C light in the presence of acetic acid as a trapping agent and the photoproducts were identified using 1 H NMR spectroscopy, gas chromatography/electron-impact mass spectrometry, and high resolution accurate mass mass spectrometry. The products identified were the germanes nBu 3 GeH, nBu 3 GeOAc, and Ph 2 Ge(H)OAc (OAc = C 2 H 3 O 2 ) and the diger- [a]

The fluorine-substituted branched oligogermane (Ph 3 Ge) 3 GeF was successfully synthesized from (Ph 3 Ge) 3 GeH and [Ph 3 C][BF 4 ] after several unfruitful attempts using other synthetic methods and was formed as a mixture with Ph 3 GeF. Pure (Ph 3 Ge) 3 GeF could be obtained from the reaction mixture by successive recrystallizations and was characterized by elemental analysis and NMR ( 1 H, 13 C, and 19 F) spectroscopy, including a variable-temperature 19 F NMR study to investigate the presence or absence of hydrogen bonding in this species. The oligogermane (Ph 3 Ge) 3 GeF is indefinitely stable in the solid state under an inert atmosphere, but gradually decomposes to Ph 3 GeF and other unidentified products in solution. The X-ray crystal structure of (Ph 3 Ge) 3 GeF was obtained and represents the only crystallographically characterized germanium−fluorine compound having unsupported Ge−Ge bonds. The Ge 4 framework of the oligogermane (Ph 3 Ge) 3 GeF is isostructural with the other previously prepared halogen-substituted analogues (Ph 3 Ge) 3 GeX (X = Cl, Br, I). The position of the fluorine atom in the structure of (Ph 3 Ge) 3 GeF is disordered by displacement of a chlorine atom 39% of the time. The UV/visible spectrum and the cyclic and differential pulse voltammograms of (Ph 3 Ge) 3 GeF were obtained, and the relative energies of the frontier orbitals were determined using DFT computations.

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Reaction of Ge 2 Ph 6 (1) with trichloroacetic acid at 95 • C in toluene for 4 days yields a mixture of the two digermanes (Cl 3 CCOO)Ph 2 GeGePh 2 (OOCCCl 3 ) (2) and Ph 3 GeGePh 2 (OOCCCl 3 ) (3) that are converted to a mixture of ClPh 2 GeGePh 2 Cl (4) and Ph 3 GeGePh 2 Cl (5) using ethereal HCl. Treatment of the mixture of 4 and 5 with LiAlH 4 affords the two digermanes HPh 2 GeGePh 2 H (6) and Ph 3 GeGePh 2 H (7). The digermane 7 was separated from 6 by crystallization and its X-ray crystal structure was determined. Digermane 7 crystallizes in two different morphologies, where one contains three independent molecules in the unit cell (7a) and the other contains only one independent molecule (7b). The Ge -Ge bond distances in these two structures are 2.4234(7) Å (average) in 7a and 2.4213(5) Å in 7b. Compound 7 is thermally unstable and releases Ph 3 GeH upon heating this material to 200 • C in the solid state, with concomitant formation of the germylene Ph 2 Ge: that polymerizes.