Dirheniumdecacarbonyl

Pale yellow solid

Fixed

2.87 g · cm -3 ( 20 ° C)

170 ° C

Insoluble in water

Attention

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Dirheniumdecacarbonyl ( often referred to as Rheniumdecacarbonyl ) was the first known stable metal carbonyl of the element rhenium and was synthesized by Hieber, who was a pioneer of metal carbonyl chemistry, 1941.

Representation

The solid is made ​​of rhenium (VII ) oxide prepared directly by reduction with carbon monoxide.

It can also be obtained from Kaliumrhenat.

Properties

Re2 (CO) 10 is a metal carbonyl with metal -metal bond and thus according to the definition of Cotton to be regarded as metal clusters. The equatorial Carboylliganden of this in the 0 oxidation state rhenium fragment Re ( CO) 5 have each other in the molecule a staggered arrangement. The metal -metal bond length is 304 pm, and was determined from the data of a single-crystal.

Re2 (CO) 10 satisfies the 18- electron rule: ( rhenium has 7 outer electrons (14 ), each carbonyl controls two electrons in (20 ), the metal -metal bond has 2 electrons: 14 20 2 = 36 ).

It is in the form of air-stable, colorless leaflets ( from petroleum ether ). At higher temperatures, decomposition takes place under metal deposition. It is insoluble in water, moderately soluble in aliphatic hydrocarbons and soluble in tetrahydrofuran and methylene chloride.

Reactions

• A classic response to anionic carbonyl complexes is the base reaction by Hieber. In this reaction, the base is OH at the carbonyl carbon atom attacking, the primary adduct decomposes and carbonylmetalate is formed. For example, HRe ( CO) is a 5

• Substituting Dirheniumdecarcarbonly or its homologous compounds Mn2 (CO) 10 and Tc2 (CO) 10 in order with halogens, one obtains the carbonyl halides: M2 (CO) 10 Hal 2 → 2 Halm (CO ) 5 In this way BrMn (CO) 5, CLmn (CO) 5, CLRE (CO) 5 and BrRe (CO) 5, etc. are available.

• The combination of both said method is used for the synthesis of mixed metal carbonyls: BrMn (CO) 5 - Re ( CO) 5 → MNRE (CO) 10

• Other reactions are based on ligand exchange reactions and / or thermal or photochemical treatment of the carbonyls.

Use

The substance is used as the starting molecule for other rhenium compounds, in particular for clusters used because the CO ligands can be easily replaced by other ligands.