Rhodium carbonyl chloride

Last updated
Rhodium carbonyl chloride
Rh2Cl2(CO)4.svg
Rh2Cl2(CO)4.jpg
Names
IUPAC name
Di-μ-chloro-tetracarbonyldirhodium(I)
Other names
Rhodium carbonyl chloride(I), Rhodium(I) carbonyl chloride, Rhodium(I) dicarbonyl chloride dimer, Tetracarbonyldi-μ−chlorodirhodium(I), Dirhodium tetracarbonyl dichloride
Identifiers
ECHA InfoCard 100.035.021 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
Properties
C4O4Cl2Rh2
Molar mass 388.76
Appearancered brown volatile solid
Density 2.708 g/cm−3
Melting point 120-125 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Rhodium carbonyl chloride is an organorhodium compound with the formula Rh2Cl2(CO)4. It is a red-brown volatile solid that is soluble in nonpolar organic solvents. It is a precursor to other rhodium carbonyl complexes, some of which are useful in homogeneous catalysis.

Contents

Structure

The molecule consists of two planar Rh(I) centers linked by two bridging chloride ligands and four CO ligands. X-ray crystallography shows that the two Rh(I) centers are square planar with the dihedral angle of 53° between the two RhCl2 planes. The metals are nonbonding. [1]

Synthesis and reactions

First prepared by Walter Hieber, [2] it is typically prepared by treating hydrated rhodium trichloride with flowing carbon monoxide, according to this idealized redox equation:

2 RhCl3(H2O)3 + 6 CO → Rh2Cl2(CO)4 + 2 COCl2 + 6 H2O. [3]

The complex reacts with triphenylphosphine to give the bis(triphenylphosphine)rhodium carbonyl chloride:

Rh2Cl2(CO)4 + 4 PPh3 → 2 trans-RhCl(CO)(PPh3)2 + 2 CO

With chloride salts, the dichloride anion forms:

Rh2Cl2(CO)4 + 2 Cl → 2 cis-[RhCl2(CO)2]

With acetylacetone, rhodium carbonyl chloride reacts to give dicarbonyl(acetylacetonato)rhodium(I).

The dimer reacts with a variety of Lewis bases (:B) to form adducts RhCl(CO)2:B. Its reaction with tetrahydrothiophene and the corresponding enthalpy are:

1/2 Rh2Cl2(CO)4 + :S(CH2)4 → RhCl(CO)2:S(CH2)4  ΔH = -31.8 kJ mol−1

This enthalpy corresponds to the enthalpy change for a reaction forming one mole of the product, RhCl(CO)2:S(CH2)4, from the acid dimer. The dissociation energy for rhodium(I) dicarbonyl chloride dimer, which is an energy contribution prior to reaction with the donor,

Rh2Cl2(CO)4 → 2 RhCl(CO)2

has been determined by the ECW model to be 87.1 kJ mol−1

N-heterocyclic carbene (NHC) ligands react with rhodium carbonyl chloride to give monomeric cis-[RhCl(NHC)(CO)2] complexes. The IR spectra of these complexes have been used to estimate the donor strength of NHCs. [4] [5]

Related Research Articles

<span class="mw-page-title-main">Wilkinson's catalyst</span> Chemical compound

Wilkinson's catalyst (chlorido­tris(triphenylphosphene)­rhodium(I)) is a coordination complex of rhodium with the formula [RhCl(PPh3)3], where 'Ph' denotes a phenyl group. It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.

<span class="mw-page-title-main">Vaska's complex</span> Chemical compound

Vaska's complex is the trivial name for the chemical compound trans-carbonylchlorobis(triphenylphosphine)iridium(I), which has the formula IrCl(CO)[P(C6H5)3]2. This square planar diamagnetic organometallic complex consists of a central iridium atom bound to two mutually trans triphenylphosphine ligands, carbon monoxide and a chloride ion. The complex was first reported by J. W. DiLuzio and Lauri Vaska in 1961. Vaska's complex can undergo oxidative addition and is notable for its ability to bind to O2 reversibly. It is a bright yellow crystalline solid.

<span class="mw-page-title-main">Rhodium(III) chloride</span> Chemical compound

Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of n, the material is either a dense brown solid or a soluble reddish salt. The soluble trihydrated (n = 3) salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid and hydroformylation.

A transition metal carbene complex is an organometallic compound featuring a divalent carbon ligand, itself also called a carbene. Carbene complexes have been synthesized from most transition metals and f-block metals, using many different synthetic routes such as nucleophilic addition and alpha-hydrogen abstraction. The term carbene ligand is a formalism since many are not directly derived from carbenes and most are much less reactive than lone carbenes. Described often as =CR2, carbene ligands are intermediate between alkyls (−CR3) and carbynes (≡CR). Many different carbene-based reagents such as Tebbe's reagent are used in synthesis. They also feature in catalytic reactions, especially alkene metathesis, and are of value in both industrial heterogeneous and in homogeneous catalysis for laboratory- and industrial-scale preparation of fine chemicals.

<span class="mw-page-title-main">Dicarbonyltris(triphenylphosphine)ruthenium(0)</span> Chemical compound

Dicarbonyltris(triphenylphosphine)ruthenium(0) or Roper's complex is a ruthenium metal carbonyl. In it, two carbon monoxide ligands and three triphenylphosphine ligands are coordinated to a central ruthenium(0) center.

<span class="mw-page-title-main">Pentamethylcyclopentadiene</span> Chemical compound

1,2,3,4,5-Pentamethylcyclopentadiene is a cyclic diene with the formula C5(CH3)5H, often written C5Me5H, where Me is CH3. It is a colorless liquid.

<span class="mw-page-title-main">Tebbe's reagent</span> Chemical compound

Tebbe's reagent is the organometallic compound with the formula (C5H5)2TiCH2ClAl(CH3)2. It is used in the methylidenation of carbonyl compounds, that is it converts organic compounds containing the R2C=O group into the related R2C=CH2 derivative. It is a red solid that is pyrophoric in the air, and thus is typically handled with air-free techniques. It was originally synthesized by Fred Tebbe at DuPont Central Research.

Martin Arthur Bennett FRS is an Australian inorganic chemist. He gained recognition for studies on the co-ordination chemistry of tertiary phosphines, olefins, and acetylenes, and the relationship of their behaviour to homogeneous catalysis.

<span class="mw-page-title-main">Organoiridium chemistry</span> Chemistry of organometallic compounds containing an iridium-carbon bond

Organoiridium chemistry is the chemistry of organometallic compounds containing an iridium-carbon chemical bond. Organoiridium compounds are relevant to many important processes including olefin hydrogenation and the industrial synthesis of acetic acid. They are also of great academic interest because of the diversity of the reactions and their relevance to the synthesis of fine chemicals.

<span class="mw-page-title-main">Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium</span> Chemical compound

Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium is the organoruthenium half-sandwich compound with formula RuCl(PPh3)2(C5H5). It as an air-stable orange crystalline solid that is used in a variety of organometallic synthetic and catalytic transformations. The compound has idealized Cs symmetry. It is soluble in chloroform, dichloromethane, and acetone.

<span class="mw-page-title-main">Hexadecacarbonylhexarhodium</span> Chemical compound

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. It is the principal binary carbonyl of rhodium.

<span class="mw-page-title-main">Organoruthenium chemistry</span>

Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therapy. The chemistry has some stoichiometric similarities with organoiron chemistry, as iron is directly above ruthenium in group 8 of the periodic table. The most important reagents for the introduction of ruthenium are ruthenium(III) chloride and triruthenium dodecacarbonyl.

<span class="mw-page-title-main">Organorhodium chemistry</span> Field of study

Organorhodium chemistry is the chemistry of organometallic compounds containing a rhodium-carbon chemical bond, and the study of rhodium and rhodium compounds as catalysts in organic reactions.

<span class="mw-page-title-main">Dichlorotris(triphenylphosphine)ruthenium(II)</span> Chemical compound

Dichlorotris(triphenylphosphine)ruthenium(II) is a coordination complex of ruthenium. It is a chocolate brown solid that is soluble in organic solvents such as benzene. The compound is used as a precursor to other complexes including those used in homogeneous catalysis.

<span class="mw-page-title-main">Metal-phosphine complex</span>

A metal-phosphine complex is a coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0).

<span class="mw-page-title-main">Tris(triphenylphosphine)rhodium carbonyl hydride</span> Chemical compound

Carbonyl hydrido tris(triphenylphosphine)rhodium(I) [Carbonyl(hydrido)tris(triphenylphosphane)rhodium(I)] is an organorhodium compound with the formula [RhH(CO)(PPh3)3] (Ph = C6H5). It is a yellow, benzene-soluble solid, which is used industrially for hydroformylation.

<span class="mw-page-title-main">Chlorobis(cyclooctene)iridium dimer</span> Chemical compound

Chlorobis(cyclooctene)iridium dimer is an organoiridium compound with the formula Ir2Cl2(C8H14)4, where C8H14 is cis-cyclooctene. Sometimes abbreviated Ir2Cl2(coe)4, it is a yellow, air-sensitive solid that is used as a precursor to many other organoiridium compounds and catalysts.

<span class="mw-page-title-main">Chlorobis(ethylene)rhodium dimer</span> Chemical compound

Chlorobis(ethylene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C2H4)4. It is a red-orange solid that is soluble in nonpolar organic solvents. The molecule consists of two bridging chloride ligands and four ethylene ligands. The ethylene ligands are labile and readily displaced even by other alkenes. A variety of homogeneous catalysts have been prepared from this complex.

<span class="mw-page-title-main">Dicarbonyl(acetylacetonato)rhodium(I)</span> Chemical compound

Dicarbonyl(acetylacetonato)rhodium(I) is an organorhodium compound with the formula Rh(O2C5H7)(CO)2. The compound consists of two CO ligands and an acetylacetonate. It is a dark green solid that dissolves in acetone and benzene, giving yellow solutions. The compound is used as a precursor to homogeneous catalysts.

<span class="mw-page-title-main">Bis(triphenylphosphine)rhodium carbonyl chloride</span> Chemical compound

Bis(triphenylphosphine)rhodium carbonyl chloride is the organorhodium complex with the formula [RhCl(CO)(PPh3)2]. This complex of rhodium(I) is a bright yellow, air-stable solid. It is the Rh analogue of Vaska's complex, the corresponding iridium complex. With regards to its structure, the complex is square planar with mutually trans triphenylphosphine (PPh3) ligands. The complex is a versatile homogeneous catalyst.

References

  1. Walz, Leonhard; Scheer, Peter "Structure of di-μ-chlorobis[dicarbonylrhodium(I)]" Acta Crystallographica Section C 1991, C47, 640-41. doi : 10.1107/S0108270190009404
  2. Hieber, W.; Lagally, H. "Über Metallcarbonyle. XLV. Das Rhodium im System der Metallcarbonyle (Metal carbonyls. XLV. Rhodium in the system of metal carbonyls)" Zeitschrift für Anorganische und Allgemeine Chemie 1943, volume 251, pp. 96-113. doi : 10.1002/zaac.19432510110
  3. McCleverty, J. A.; Wilkinson, G. "Dichlorotetracarbonyldirhodium (rhodium carbonyl chloride)" Inorganic Syntheses 1966, volume 8, pp. 211-14. doi : 10.1002/9780470132463.ch4
  4. Nonnenmacher, Michael; Buck, Dominik M; Kunz, Doris (23 August 2016). "Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes". Beilstein Journal of Organic Chemistry. 12: 1884–1896. doi:10.3762/bjoc.12.178. PMC   5082490 . PMID   27829895.
  5. Huynh, Han Vinh (30 March 2018). "Electronic Properties of N-Heterocyclic Carbenes and Their Experimental Determination". Chemical Reviews. 118 (19): 9457–9492. doi:10.1021/acs.chemrev.8b00067. PMID   29601194.