Über polygermane

Synthesis, structures and reactivity of novel germanium(ii) aryloxide and arylsulfide complexes

“…The germanium-germanium separation is 3.209 Å in 1 and is 3.212 Å in 2, both of which are well outside the range (typically 2.4-2.6 Å) normally attributed to direct Ge-Ge bonding. [16][17][18][19][20][21][22][23] Germylenes containing ligands bound though a N-or O-atom typically do not dimerize to form digermenes while this process is common in alkyl-substituted germylenes with carbon-bound ligands. This has been attributed to the lone pair of electrons being more tightly held to the Ge metal center in these types of materials relative to their alkyl-substituted counterparts.…”

Syntheses, structures and properties of linear and branched oligogermanes

“…The most detailed investigations involving oligogermanes having single Ge-Ge bonds were reported in a series of nineteen publications describing the spectra, structures and reactivity of several catenates having between two and six germanium atoms in the Ge-Ge backbone that appeared in the 1980s, 25-43 including the pentagermane Ge 5 Ph 12 (6). 29 However, an improved synthetic method for oligogermanes that provides discrete compounds in high yields in most cases which involves the use of samarium(II) iodide as the reducing agent was recently described. 44,45 Prior to our investigations, a few examples of the generation of germanium-germanium bonds using the hydrogermolysis reaction between a germanium hydride and a germanium amide had been reported, 46,47 but the use of activated germanium hydrides such as (F 5 C 6 ) 3 GeH were postulated to be necessary for the success of this reaction (eqn 1).…”

A luminescent and dichroic hexagermane

“…The degree of s-delocalization present in 1 is manifested in its UV/visible spectrum (Fig. 2) as the l max for 1 was observed at 310 nm, which is red shifted from those observed for the other oligogermanes Ge 5 Ph 12 , Ge 4 Ph 10 , Ge 3 Ph 8 , and Ge 2 Ph 6 that were found at 295, 17,20 282, 18 249, 18 and 238 nm, 18 respectively. In fact, the l max for 1 appears at the lowest energy for any reported discrete linear or branched oligogermane, and is also on the order of the l max values observed for several polygermane systems (R 1 R 2 Ge) n that range from 293-338 nm.…”

“…These metric parameters are similar to those found in other structurally characterized linear oligogermanes. 12,13,[15][16][17][18][19] The distance across the entire Ge 6 chain measures 14.8260(2) Å, and the most important structural feature of 1 is that it contains four central trans-coplanar germanium atoms and two terminal germanium atoms that are displaced out of the plane. Thus, all six germanium atoms in 1 are disposed such that overlap of their Scheme 1 Synthetic scheme for the preparation of hexagermane 1.…”