Hexadecacarbonylhexarhodium

Source: Wikipedia, the free encyclopedia.
Hexadecacarbonylhexarhodium
Names
IUPAC name
Hexadecacarbonylhexarhodium
Other names
Hexarhodium hexadecacarbonyl
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.044.539 Edit this at Wikidata
EC Number
  • 249-009-3
  • InChI=1S/16CO.6Rh/c16*1-2;;;;;;
    Key: SZQABOJVTZVBHE-UHFFFAOYSA-N
  • [C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[Rh].[Rh].[Rh].[Rh].[Rh].[Rh]
Properties
C16O16Rh6
Molar mass 1065.62 g/mol
Appearance purple-brown solid
Melting point 235 °C (455 °F; 508 K)
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H302, H312, H332
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P312, P322, P330, P363, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Hexadecacarbonylhexarhodium is a metal carbonyl cluster with the formula Rh6(CO)16. It exists as purple-brown crystals that are slightly soluble in dichloromethane and chloroform.[1] It is the principal binary carbonyl of rhodium.

Discovery and synthesis

Rh6(CO)16 was first prepared by

RhCl3·3H2O at 80–230 °C and 200 atm carbon monoxide with silver or copper as a halide acceptor. Hieber correctly formulated the compound as a binary carbonyl, but suggested the formula Rh4(CO)11, i.e., CO/Rh ratio of 2.75.[2] The correct formula and structure was subsequently established by Dahl et al. using X-ray crystallography. The correct CO/Rh ratio is 2.66.[3]

Relative to the original preparation, the carbonylation of a mixture of anhydrous

rhodium trichloride and iron pentacarbonyl was shown to give good yields of Rh6(CO)16.[4] Other compounds of rhodium are also effective precursors such as [(CO)2Rh(μ-Cl)]2 and rhodium(II) acetate:[1]

3 Rh2(O2CCH3)4 + 22 CO + 6 H2O → Rh6(CO)16 +  6 CO2 + 12 CH3COOH
3 [(CO)2RhCl]2 + 4 CO + 6 Cu → Rh6(CO)16 + 6 CuCl

It also arises quantitatively by thermal decomposition of tetrarhodium dodecacarbonyl in boiling hexane:[5]

3 Rh4(CO)12 → 2 Rh6(CO)16 + 4 CO

Reactions

At least some of the CO ligands can be displaced by donor ligands.[5]

Rh6(CO)16 catalyzes a number of organic reactions including hydrogenation and hydroformylation.[4]

References

  1. ^
    doi:10.1002/9780470132470.ch15
    .
  2. doi:10.1002/zaac.19432510110
    .
  3. doi:10.1021/ja00891a040
    .
  4. ^
    doi:10.1016/S0022-328X(00)87682-2
    .
  5. ^
    doi:10.1002/9780470132623.ch37
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Hexadecacarbonylhexarhodium&oldid=1125203478"