Half sandwich compound

Source: Wikipedia, the free encyclopedia.

Half sandwich compounds, also known as piano stool complexes, are

petrol
.

  • MMT is a commercially useful antiknock compound.
    MMT is a commercially useful antiknock compound.
  • CpCo(CO)2 is a catalyst for the synthesis of pyridines.
    CpCo(CO)2 is a catalyst for the synthesis of pyridines.
  • (C4H4)Fe(CO)3.
    (C4H4)Fe(CO)3.
  • CpFe(CO)2I is an example of a piano stool complex with two different monodentate ligands.
    CpFe(CO)2I is an example of a piano stool complex with two different monodentate ligands.
  • The diruthenium of cymene is readily cleaved by ligands to give monoRu half-sandwich derivatives.
    The diruthenium of cymene is readily cleaved by ligands to give monoRu half-sandwich derivatives.
  • Cycloheptatriene molybdenum tricarbonyl
    Cycloheptatriene molybdenum tricarbonyl
  • Cp2V2(CO)5 featuring a pair of semi-bridging CO ligands.[2]
    Cp2V2(CO)5 featuring a pair of semi-bridging CO ligands.[2]

(η5-C5H5) piano stool compounds

Half sandwich complexes containing cyclopentadienyl ligands are common. Well studied examples include (η5-C5H5)V(CO)4, (η5-C5H5)Cr(CO)3H, (η5-CH3C5H4)Mn(CO)3, (η5-C5H5)Cr(CO)3H, [(η5-C5H5)Fe(CO)3]+, (η5-C5H5)V(CO)4I, and (η5-C5H5)Ru(NCMe)+
3. (η5-C5H5)Co(CO)2 is a two-legged piano stool complex. Bulky cyclopentadienyl ligands such as 1,2,4-C5H2(tert-Bu)3− form unusual half-sandwich complexes.[3]

(η6-C6H6) piano stool compounds

In

carbonyl
ligands, and so the structure resembles a benzene seat mounted on three carbonyl legs tethered by the metal atom.

Cr and Mn(I) (η6-C6H6) piano stool complexes

Piano stool complexes of the type (η6-C6H6)M(CO)3 are typically synthesized by heating the appropriate

arene ligands containing thermally fragile substituents.[8]

Reactivity of (η6-C6H6)Cr(CO)3

The benzene ligand in (η6-C6H6)Cr(CO)3Mi is prone to deprotonation.

Organolithium compounds form adducts featuring cyclohexadienyl ligands. Subsequent oxidation of the complex results in the release of a substituted benzene.[10][11] Oxidation of the chromium atom by I2 and other iodine reagents has been shown to promote exchange of arene ligands, but the intermediate chromium iodide species has not been characterized.[12]

(η6-C6H6)Cr(CO)3 complexes exhibit "cine" and "tele" nucleophilic aromatic addition.

Arene substitution patterns
).

Reflecting its increased acidity, the benzene ligand can be lithiated with

organolithium compound serves as a nucleophile in various reactions, for example, with trimethylsilyl chloride:[citation needed
]

(η6-C6H6)Cr(CO)3 is a useful

catalyst for the hydrogenation of 1,3-dienes. The product alkene results from 1,4-addition of hydrogen. The complex does not hydrogenate isolated double bonds.[citation needed
]

A variety of arenes ligands have been installed aside from benzene.

ligands may be employed to improve ligand exchange and thus the turnover rates for (η6-C6H6)M(CO)3 complexes.[8]: 248 (η6-C6H6)M(CO)3 complexes have been incorporated into high surface area porous materials.[15]

(η6-C6H6)M(CO)3 complexes serve as models for the interaction of metal carbonyls with graphene and carbon nanotubes.[16] The presence of M(CO)3 on extended π-network materials has been shown to improve electrical conductivity across the material.[17]

Reactivity of [(η6-C6H6)Mn(CO)3]+

Typical arene tricarbonyl piano stool complexes of Mn(I) and Re(I) are cationic and thus exhibit enhanced reactivity toward nucleophiles. Subsequent to nucleophilic addition, the modified arene can be recovered from the metal.[18][19]

(η6-C6H6)Ru complexes

1,3-cyclohexadienes.[21] Work is also conducted on their potential as anticancer drugs.[22]

(η6-C6H6)RuCl2 readily undergoes ligand exchange via cleavage of the chloride bridges, making this complex a versatile precursor to Ru(II) piano stool derivatives.[23]

References

  1. OCLC 1004583759
    .
  2. doi:10.1021/ic50211a052
    .
  3. S2CID 105376454
    .
  4. ^ Natta, G.; Ercoli, R.; F., Calderazzo (1958). "(η-C6H6)Cr(CO)3". Chimica e Industria. 40: 1003.
  5. doi:10.1002/cber.19580911231
    .
  6. doi:10.1002/cber.19570901117
    .
  7. doi:10.1021/ja01518a065
    .
  8. ^
    ISBN 978-1-891389-53-5
    .
  9. ISBN 978-0-470-25762-3
    .
  10. ISBN 978-3-540-46128-9
    .
  11. ISBN 978-0471936237
    .
  12. doi:10.1021/ja00317a052
    .
  13. doi:10.1021/om00004a065
    .
  14. PMID 21413775
    .
  15. doi:10.1016/j.cattod.2011.10.019
    .
  16. doi:10.1016/j.ijms.2008.01.010
    .
  17. doi:10.1016/j.ccr.2008.04.014
    .
  18. doi:10.1016/s0020-1693(00)94897-7
    .
  19. doi:10.1021/om00072a040
    .
  20. PMID 17960897
    .
  21. ISBN 9780470132524
    .
  22. PMID 21258628. {{cite book}}: |journal= ignored (help
    )
  23. doi:10.1016/j.ccr.2008.04.014
    .
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