Germyl

 ( Germanium Compounds ) 

Germyl, trihydridogermanate(1-), trihydrogermanide, trihydridogermyl or according to IUPAC Red Book: germanide is an anion containing germanium bounded with three hydrogens, with formula . Germyl is the IUPAC term for the – group. For less electropositive elements the bond can be considered covalent rather than ionic as "germanide" indicates. Germanide is the base for germane when it loses a proton.

The first germyl compound to be discovered was sodium germyl. Germane was reacted with sodium dissolved in liquid ammonia to produce sodium germyl. Other alkali metal germyl compounds are known. There are also numerous transition metal complexes that contain germyl as a ligand.

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Formation Alkali metal germyl compounds have been made by reacting germane with the alkali metal dissolved in liquid ammonia, or other non-reactive solvent.

Transition metal complexes cam be made by using lithium aluminium hydride to reduce a trichlorogermyl complex (−), which in turn can be made from the transition metal complex chloride and .

Salt elimination can be used in a reaction with monochlorogermane and a sodium salt of a transition metal anion:

.

In the gas phase, the germyl anion can be made from germane by capturing an electron with more than 8 eV of energy:

The germyl radical can be produced and immobilised in molecular form by exposing germane to vacuum ultraviolet light in a solid argon matrix. On heating, digermane is formed:

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Properties Germyl compounds react with water, so water cannot be used as a solvent. Liquids that have been used as solvents include liquid ammonia, ethyl amine, diglyme, or hexamethylphosphoramide. The choice of solvent depends on the temperature desired, whether alkali metals are going to be dissolved, whether the solvent needs to be distilled, and also if it reacts with the solute.

The bond between the metal ion and the germyl ion may be purely ionic, but may also be bonded via two bridging hydrogen atoms.

The energy to rip a hydrogen atom off germane to make the neutral radical is . GeH₄ → GeH₃^• + H^•. Electron affinity for the radical is 1.6 eV: GeH₃^• + e⁻ → GeH₃⁻.

Gas phase acidity of germane is ΔG is ; ΔH is for .

Both the anion and radical have C_3v symmetry, and are shaped as a triangular pyramid with germanium at the top, and three hydrogen atoms at the bottom. In the radical, the H-Ge-H angle is 110°. In the anion the H-Ge-H angle is about 93°.

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Reactions Germyl compounds gradually decompose at room temperature by releasing hydrogen and forming a metal germide.

Germyl compounds react with alkyl halides to substitute the germyl − group for the halogen. With aromatic halide compounds, dihalomethanes, or neopentyl haldes they replace the halogen with hydrogen. Organogermanium compounds that can be produced include methyl germane, dimethyl germane, digermyl methane, digermyl ethane, digermyl propane.

The germyl ion reacts with water to yield germane:

Sodium germyl reacts with oxygen to form an orthogermanate:

This loses water at room temperature.

Kη⁵-C₅H₅)Mn(CO)₂GeH₃ reacts with acid to yield η⁵-C₅H₅)Mn(CO)₂₂Ge which has a Mn=Ge=Mn linkage in it.

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List

	Sodium Trihydrogermanide							white
P(GeH3)3
KGeH3			cubic		a=7.235		2.003	NaCl structure
K(18crown-6)(thf)GeH3		451.13	monoclinic	Pc	a=13.8587 b=9.9670 c=16.9439 β=107.206 Z=4	2235.7	1.34	colourless
K(15crown-5)2GeH3		555.23	tetrahedral	I	a=12.685 c=16.985 Z=4	2733.0	1.349	colourless
K(12crown-4)2GeH3		467.13	monoclinic	C2/ c	a=40.7694 b=6.623 c=29.6746 β=97.450 Z=16	9144.9	1.357	colourless
KV(CO)3(η5-C5H5)GeH3
PPh4V(CO)3(η5-C5H5)GeH3			orthorhombic	Pcab	a=17.47 b=15.68 c=21.49 Z=8	5886	1.39	yellow
KCr(CO)5GeH3
PPh4Cr(CO)5GeH3			monoclinic	C2/ c	a=22.301 b=6.989 c=18.002 β=? Z=4	2788.5	1.45	yellow
Mn(GeH3)(CO)5
Mn(GeH3)(CO)2(PPh(OEt)2)3								pale yellow
Mn(GeH3)(CO)3(PPh(OEt)2)2		610.96	triclinic	P	a=10.118 b=11.060 c=13.009 α=97.859 β=98.612 γ=92.856 Z=2	1422.3	1.427	pale yellow
Mn(GeH3)(CO)2(P(OEt)3)3								pale yellow
Mn(GeH3)(CO)3(P(OEt)3)2								pale yellow
Kη5-C5H5)Mn(CO)2GeH3
(CH3)4Nη-CH3C5H4Mn(CO)2GeH3			triclinic	P	a=6.948 b=9.658 c=11.784 α=89.57 β=77.37 γ=88.05 Z=2	772	1.45
(CH3)4Nη-CH3C5H4Mn(CO)2GeH3			triclinic	P	a=6.958 b=9.658 c=11.784 α=89.57 β=77.37 γ=88.05 Z=2	772	1.46
(GeH3)2Fe(CO)4	digermyltetracarbonyliron							mp 71°C colourless
GeH3(H)Fe(CO)4	monogermylhydridotetracarbonyliron							mp −30°C colourless
GeH3Fe(C5H5)(CO)2	Germyl(cyclopentadienyl)dicarbonyliron							mp 81°C yellow
Fe(CO)4(GeH2GeH3)(GeH3)
Fe(CO)4(GeH3)(GeMe3)
{Fe(CO)4(GeH2)}2								-Fe-Ge-Fe-Ge- ring
KCo2(CO)7GeH3
PPh4Co2(CO)7GeH3]
KCo-(CO)(η5C6H5)GeH3
PPh4Co-(CO)(η5C6H5)GeH3
KCo-(CO)(η5C6(CH3)5)GeH3
PPh4Co-(CO)(η5C6(CH3)5)GeH3
K(η5-C5H5)-Mn(CO)2GeH3
KNi(CO)3GeH3
PPh4Ni(CO)3GeH3			monoclinic	C2	a=16.855 b=7.098 c=15.189 β=134.71 Z=2	1291.5	1.43	orange yellow
KNi(CO)2(PPh3)GeH3
PPh4Ni(CO)2(PPh3)GeH3			monoclinic	P21/ n	a=10.37 b=22.37 c=16.95 β=96.23 Z=4	2910.6	1.74	orange yellow
As(GeH3)3
Rb(18crown-6)(thf)GeH3		497.50	monoclinic	Cc	a=13.8336 b=9.9878 c=16.9893 β=107.417 Z=4	2239.7	1.475	colourless
RbGeH3					a=7.518		2.518
KNb(CO)3(η5-C5H5)GeH3
PPh4Nb(CO)3(η5-C5H5)GeH3
KMo(CO)5GeH3
PPh4Mo(CO)5GeH3			monoclinic	C2/ c	a=22.25 b=7.021 c=18.545 β=96.14 Z=4	2881	1.5	yellow
Ru(GeH3)(η5-C5H5)(PPh3)P(OMe)3		628.12	monoclinic	P21/ c	a=17.932 b=10.067 c=16.375, β=114.508° Z=4	2689.6	1.551	yellow
Ru(GeH3)(η5-C5H5)(PPh3)P(OEt)3								yellow
Ru(GeH3)(η5-C5H5)(PPh3)PPh(OEt)2								yellow
Ru(GeH3)(η5-C9H7)(PPh3)P(OMe)3								yellow
Ru(GeH3)(η5-C9H7)(PPh3)P(OEt)3								yellow
Ru(GeH3)(η5-C9H7)(PPh3)PPh(OEt)2								yellow
Ru(GeH3)(Tp)(PPh3))P(OEt)3								yellow
Ru(GeH3)(Tp)(PPh3)PPh(OEt)2								yellow
cis-Ru(dppe)2(GeH3)H•C6H6		1014.4	triclinic	P	a 12.3464 b 13.2412 c 16.2053, α 90.055° β 98.868° γ 116.164° Z=2	2342.3	1.438
trans-Ru(dppe)2(GeH3)H
cis-Ru(depe)2(GeH3)H
trans-Ru(depe)2(GeH3)H
cis-Ru(dmpe)2(GeH3)H
trans-Ru(dmpe)2(GeH3)H
cis-Ru(DuPhos)2(GeH3)H		790.38	orthorhombic	P212121	a 10.1222 b 18.4327 c 19.425 Z=4	3624.4	1.448
Ru(GeH3)(Cp′)L Cp′=η5-C5Me5 L=1,2-bis(diphenyl)-1,2-diphenylethane
Ru(GeH3)(Cp′)L Cp′=η5-C9H7 L=1,2-bis(diphenyl)-1,2-diphenylethane
Sb(GeH3)3	trigermylstibine
Cs(18crown-6)2GeH3		734.12	tetrahedral	P4/ n	a=13.2513 c=19.0577 Z=4	3346.5	1.457	colourless
CsGeH3			orthorhombic		a=5.1675 b=14.435 c=5.9664		3.111
KW(CO)5GeH3
PPh4W(CO)5GeH3			monoclinic	C2/ c	a=22.227 b=7.025 c=18.529 β=96.11 Z=4	2883.2	1.71	yellow
GeH3Re(CO)5	Germylpentacarbonylrhenium							colourless mp 53-54°C
GeH2Re(CO)52	bis(pentacarbonylrhenium)germane
Re(GeH3)(CO)2(PPh(OEt)2)3								white
Re(GeH3)(CO)3(PPh(OEt)2)2								white
Re(GeH3)(CO)2(P(OEt)3)3								white
Re(GeH3)(CO)3(P(OEt)3)2								white
KRe(CO)2(η5-C5H5)GeH3
PPh4Re(CO)2(η5-C5H5)GeH3
Os(GeH3)(Tp)(PPh3)P(OMe)3 Tp = tris(pyrazolyl)borate								white

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Related

Germylidyne with formula ≡GeH has a triple bond to the metal atom.

Germylidene with base formula = has a double bond to the central metal.

Categories: Germanium Compounds, Metal Hydrides, Anions

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