Chemistry:Bromopentacarbonylrhenium(I)

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Bromopentacarbonylrhenium(I)
Bromopentacarbonylrhenium(I)-3D-balls.png
Names
IUPAC name
Bromidopentacarbonylrhenium
Identifiers
3D model (JSmol)
EC Number
  • 238-084-8
Properties
Re(CO)5Br
Molar mass 406.16 g/mol
Appearance colorless
Melting point sublimes 85-90 °C (0.2 mm Hg)
Solubility in chlorocarbons soluble
Hazards
GHS pictograms GHS06: ToxicGHS07: Harmful
GHS Signal word Danger
H301, H311, H315, H319, H331, H335
P261, P264, P270, P271, P280, P301+310, P302+352, P304+340, P305+351+338, P311, P312, P321, P322, P330, P332+313, P337+313, P361, P362, P363, P403+233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Bromopentacarbonylrhenium(I) is an inorganic compound of rhenium, commonly used for the syntheses of other rhenium complexes.

Preparation

Bromopentacarbonylrhenium(I) is commercially available. It is also easily and inexpensively synthesized by the oxidation of dirhenium decacarbonyl with bromine:[1]

Re2(CO)10 + Br2 → 2 ReBr(CO)5

It was first prepared by the "reductive carbonylation" of rhenium(III) bromide:[2]

ReBr3 + 2 Cu + 5 CO → BrRe(CO)5 + 2 CuBr

Copper(I) bromide is a byproduct.

Reactions

Bromopentacarbonylrhenium(I) is a precursor to other rhenium complexes. It reacts with zinc and acetic acid to give pentacarbonylhydridorhenium (HRe(CO)5).[3]

Re(CO)5Br + Zn + HO2CCH3 → ReH(CO)5 + ZnBrO2CCH3

It also reacts with tetraethylammonium bromide in diglyme to give [NEt4]2[ReBr3(CO)3)], an important precursor to compounds containing the rhenium tricarbonyl fragment.[4]

Heating bromopentacarbonylrhenium(I) in water give the triaquo complex:

ReBr(CO)5 + 3 H2O → [Re(H2O)3(CO)3]Br + 2 CO

This route avoids the formation of the tetraethylammonium bromide byproduct, which is often difficult to remove from reaction mixtures.[5]

References

  1. Steven P. Schmidt; William C. Trogler; Fred Basolo (1990). Pentacarbonylrhenium Halides. Inorganic Syntheses. 28. pp. 154–159. doi:10.1002/9780470132593.ch42. ISBN 9780470132593. 
  2. W. Hieber; Hans Schulten (1939). "XXX. Mitteilung über Metallcarbonyle. Über Rhenium-Kohlenoxyd-Verbindungen". Zeitschrift für anorganische und allgemeine Chemie 243 (2): 164–173. doi:10.1002/zaac.19392430205. 
  3. Michael A. Urbancic; John R. Shapley (1990). Pentacarbonylhydridorhenium. Inorganic Syntheses. 28. pp. 165–8. doi:10.1002/9780470132593.ch43. ISBN 9780470132593. 
  4. R. Alberto; A Egli; U. Abram; K. Hegetschweiler; V. Gramlich; P. A. Schubiger (1994). "Synthesis and Reactivity of [NEt4]2[ReBr3(CO)3]. Formation and Structural Characterization of the Clusters [NEt4][Re33-OH)(μ-OH)3(CO)9] and [NEt4][Re2(μ-OH)3(CO)6] by alkaline titration". J. Chem. Soc., Dalton Trans. (19): 2815–2820. doi:10.1039/DT9940002815. 
  5. N. Lazarova; S. James; J. Babich; J. Zubieta (2004). "A convenient synthesis, chemical characterization and reactivity of [Re(CO)3(H2O)3]Br: the crystal and molecular structure of [Re(CO)3(CH3CN)2Br]". Inorganic Chemistry Communications 7 (9): 1023–1026. doi:10.1016/j.inoche.2004.07.006.