Bis germylenes

Intramolecularly alkoxy base-stabilized bis(germylene)-, 54, or (germylene)(silylene)-, 55, iron complexes, of type IV, were obtained from the photolysis of digermyl or germylsilyl iron complexes (equation 43)14. These are the same type of complexes noted above for base-free tungsten analogs146 involving a-elimination subsequent to photochemical elimination of CO as noted below. 

Figure 2.8.3 Arrangement of bis-germylenes of type M in the solid state...

The most distinctive structural feature of the heavier alkyne analogs is that, unlike typical triple-bonded carbon atoms, the group 14 elements are not linearly coordinated. For the digermyne, the bent geometry suggests that the Ge-Ge interaction is not a true triple bond, but that the molecule might be better viewed as a bis(germylene) ... 

A bis(chelate) structure was found for the closely related germylene [MeC(NPr )2]2Ge, which was also made from GeCl2(dioxane) and 2 equivalents of the lithium amidinate (colorless crystals, 81%). The same synthetic approach was used to make bis(amidinato) metal dichlorides of silicon and germanium in high yields (83-95%). Rapid oxidative addition of chalcogen atom sources (styrene sulfide and elemental Se) to the germylene derivatives resulted in a series... 

Bis(amido)-germylene and -stannylene react with [Pt(COD)2] to give the platinum(O) complexes [Pt(M NTMS 2)3], M = Ge or Sn.78 The stannylene complex has a trigonal-planar structure with Pt—Sn bond lengths of 2.47-2.50 A.79... 

The reaction of l,3-bis(trimethylsilyl)-l,3-diaza-2-germa(II)-indane (365) with trimethylsilyl azide to give (366) may seem to be reminiscent of several preceding transformations but, as was shown with open-chain germylenes, the process is not a cycloaddition and probably involves nitrene intermediates <89CB245>. 

Stable germylene (97) with 2,5-dimethyl-2,3,4-hexatriene and A -phenylmaleimide provided the stable germirane derivatives, bis(alkylidene)germirane (98) and bicy-clogermirane (99, Scheme 14.47). ... 

Ando and coworkers used a different approach to bis(germanimines) the reaction of bis[bis(trimethylsilyl)methyl]germylene with diazidosilanes gave in the first step N-(azidosilyl) germanimines, which reacted with a second equivalent of germylene to give bis(germanimines)375. The X-ray structures of two such compounds were determined r(Ge=N) 1.704 A. 

The photolysis of 1,2-digermacyclobutane derivatives with bulky bis(trimethylsilyl)methyl groups in a toluene solution of C6o provided the germylene and germacyclopropane adducts of Cgo (Equation 8) <2001JOM82>. 

Cycloaddition reaction of phosphaalkyne 42 and bis(2-/-butyl-4,5,6-trimethylphenyl)germylene 43 leads to germadiphosphacyclobutene 24 in 59% yield (Equation 5) <2001CC215, 2002JOM(646)39>. 

The first structural characterization of homologues of ketones (strictly speaking, of ureas), where E and Y are elements of the later rows of the periodic table, were reported in 1989 by Veith and coworkers. By sulfurization of the bis(amino)germylene 117, the germanethione 118 (Ge—Se 206.3 pm) that is stabilized by intramolecular N —Ge complexation was obtained (equation 14)163. Several analogous or similar... 

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