Synthesis and characterization of tetrakis(2,6-diethylphenyl)digermene

Multiply Bonded Germanium, Tin and Lead Compounds

“…Photolysis of cyclotrigermanes 12 or bis(trialkylsilyl)germanes 21,22 having bulky substituents gives the corresponding digermenes. For examples, digermenes 3 and 4 have been synthesized by these methods (Scheme 3).…”

“…R 1 R 2 Ge GeR 1 R 2 2 R 1 R 2 GeX 2 LiNaph (5) R 1 = R 2 = 2,6-i-Pr 2 C 6 H 3 (Dip) (6) R 1 = mesityl (Mes); R 2 = Dip (7) R 1 = R 2 = i-Pr 2 MeSi (5−10) (8) R 1 = R 2 = t-BuMe 2 Si (9) R 1 = R 2 = i-Pr 3 Si (10) R 1 = Mes; R 2 = 2,4,6-[(Me 3 Si) 2 CH] 3 C 6 H 2 (Tbt) SCHEME 4 There have already been several reports on the reduction of dichlorogermanes bearing bulky aryl groups with lithium naphthalenide (Scheme 5). Upon treatment with lithium naphthalenide, dichloro[bis(2,6-dimethylphenyl)]germane 11a and dichloro[bis(2,6-diethylphenyl)]germane 11b afforded the corresponding cyclotrigermanes 12a,b 12,24 . On the other hand, digermene 5 was obtained as a major product from dichloro[bis(2,6-diisopropylphenyl)]germane 11c under similar conditions (Scheme 5) 13 .…”

“…For example, addition of methanol gives methoxydigermanes 12,24 . In a reaction with an appropriate chalcogen source, chalcogenadigermiranes, which are [2 + 1]cycloadducts of the digermenes with chalcogen atoms, are obtained 36,37 .…”

New compounds with Ge/Ge and Ge/C multiple bonds

“…The first tetraaryldigermene, a molecule with a Ge@Ge double bond, was isolated by Masamune et al almost 25 years ago [2] and unambiguously characterised by X-ray crystallography two years later [3]. Meanwhile numerous structurally investigated digermenes with widely varying Ge@Ge bond lengths and trans-bending angles of the substituents from the GeAGe vector are known [4].…”

“…In contrast, the synthesis -by addition of diarylgermylenes to both triple bonds of 1,3-diynes -and structural characterisation of the acetylene-bridged bis(germaethenes) 1 and 2 were realised only recently [6][7][8]. On the other hand, the structures of the simplest -with regard to the diyne -molecules of this type with R = H or R = CH 3 have not yet been determined. Although the structure of the compound resulting from the addition of a germylene to tetra-1,3-diyne has not yet been elucidated on account of its extreme sensitivity, we have now succeeded in determining the structure of the product of the corresponding addition of a germylene to hexa-2,4-diyne.…”