Organogermanium compounds are organometallic compounds containing a carbon to

germanium Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors s ...

or hydrogen to germanium chemical bond. Organogermanium chemistry is the corresponding chemical science. Germanium shares group 14 in the periodic table with silicon, tin and lead, and not surprisingly the chemistry of organogermanium is in between that of

organosilicon compounds Organosilicon compounds are organometallic compounds containing carbon–silicon bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic co ...

and

organotin compound Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered by ...

s. One reason that limited

synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...

value of organogermanium compound is costs of germanium compounds. On the other hand, germanium is advocated as a non-toxic alternative to many toxic organotin reagents. Compounds like tetramethylgermanium and tetraethylgermanium are used in the microelectronics industry as precursors for germanium dioxide

chemical vapor deposition Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (substra ...

. The first organogermanium compound, tetraethylgermane, was synthesised by Winkler in 1887, by the reaction of germanium tetrachloride with diethylzinc. The organogermanium compound ''bis (2-Carboxyethylgermanium)sesquioxide'' was first reported in 1966.

Organogermanes

Organogermanes of the type R₄Ge with alkyl (R) groups are accessed through the cheapest available germanium precursor germanium tetrachloride and alkyl nucleophiles. The following trends are observed going down the carbon group: The nucleophilicity increases Sihyperconjugation effect known as the beta-silicon effect Sielectronegativity 2.55 − 2.01 = 0.54) and the combined stabilizing effect on the α-carbonion by the

allyl In organic chemistry, an allyl group is a substituent with the structural formula , where R is the rest of the molecule. It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, ...

group and the germanium atom. The germanium pendant of the Sakurai reaction was discovered in 1986: : The carbonyl group in this reaction is activated with

boron trifluoride Boron trifluoride is the inorganic compound with the formula BF3. This pungent, colourless, and toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds. Structure and bondin ...

Hydrides

Isobutylgermane (IBGe) (Me₂CHCH₂)GeH₃ is the organogermanium hydride that is a high vapor pressure liquid germanium source for MOVPE. Isobutylgermane is currently investigated as safer and less hazardous alternative to toxic

germane Germane is the chemical compound with the formula Ge H4, and the germanium analogue of methane. It is the simplest germanium hydride and one of the most useful compounds of germanium. Like the related compounds silane and methane, germane is te ...

gas in microelectronic applications.

Tris(trimethylsilyl)germanium hydride Tris, or tris(hydroxymethyl)aminomethane, or known during medical use as tromethamine or THAM, is an organic compound with the formula (HOCH2)3CNH2, one of the twenty Good's buffers. It is extensively used in biochemistry and molecular biology a ...

(Me₃Si)₃GeH has been investigated as a non-toxic alternative to many tin hydrides such as tributyltinhydride.

Other compounds

Triphenylgermanol (Ph₃GeOH) is known, existing as colorless solid. Like the isostructural silanol, it engages in hydrogen bonding in the solid-state. Many germanium

reactive intermediate In chemistry, a reactive intermediate or an intermediate is a short-lived, high-energy, highly reactive molecule. When generated in a chemical reaction, it will quickly convert into a more stable molecule. Only in exceptional cases can these comp ...

s are known:

germylene Germylenes are a class of germanium(II) compounds with the general formula :GeR2. They are heavier carbene analogs. However, unlike carbenes, whose ground state can be either singlet or triplet depending on the substituents, germylenes have exclus ...

s ( carbene pendants), germyl free radicals, germynes ( carbyne pendants). Digermynnes only exist for extremely bulky substituents. Unlike

alkyne \ce \ce Acetylene \ce \ce \ce Propyne \ce \ce \ce \ce 1-Butyne In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and n ...

s, the C-Ge-Ge-C core of these Digermynnes is nonlinear, although they are planar. The Ge-Ge distance is 2.22 Å, and the Ge-Ge-C angles are 131°. Such compounds are prepared by the reduction of bulky arylgermanium(II) halides.Philip P. Power "Bonding and Reactivity of Heavier Group 14 Element Alkyne Analogues" Organometallics 2007, volume 26, pp 4362–4372. As with silicon and contrasting with carbon, compounds containing Ge=C (germenes) and Ge=Ge (digermylenes) double bonds are rare. One example is the bulky derivatives of germabenzene, an analogue of benzene.

External links

* Tetramethylgermaniu
Datasheet commercial supplier
* Tetraethylgermaniu
Datasheet commercial supplier
* Tris(trimethylsilyl)germanium hydrid
Datasheet commercial supplier

References

{{ChemicalBondsToCarbon