Cyclopentadienylthallium

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Cyclopentadienylthallium, also known as thallium cyclopentadienide, is an organothallium compound with formula C5H5Tl. This light yellow solid is insoluble in most organic solvents, but sublimes readily. It is used as a precursor to transition metal and main group cyclopentadienyl complexes, as well as organic cyclopentadiene derivatives.[1]

Cyclopentadienylthallium
Names
IUPAC name
Thallium(I) cyclopentadienide
Other names
Thallium cyclopentadienide
5-Cyclopentadienyl)thallium
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.047.466 Edit this at Wikidata
EC Number
  • 252-229-2
  • InChI=1S/C5H5.Tl/c1-2-4-5-3-1;/h1-5H;/q-1;+1
    Key: CVEQRUADOXXBRI-UHFFFAOYSA-N
  • InChI=1/C5H5.Tl/c1-2-4-5-3-1;/h1-5H;/q-1;+1
    Key: CVEQRUADOXXBRI-UHFFFAOYAE
  • [cH-]1cccc1.[Tl+]
Properties
C5H5Tl
Molar mass 269.48 g·mol−1
Appearance Light yellow solid
Melting point 300 °C (572 °F; 573 K)
Insoluble
Hazards
GHS labelling:
GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
Danger
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
0
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Preparation and structure

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Cyclopentadienylthallium is prepared by the reaction of thallium(I) sulfate, sodium hydroxide, and cyclopentadiene:[2]

Tl2SO4 + 2 NaOH → 2 TlOH + Na2SO4
TlOH + C5H6 → TlC5H5 + H2O

The compound adopts a polymeric structure, consisting of infinite chains of bent metallocenes. The Tl---Tl---Tl angles are 130°.[3] Upon sublimation, the polymer cracks into monomers of C5v symmetry.

Applications

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Compared to other cyclopentadienyl (Cp) transfer reagents, such as cyclopentadienyl sodium, CpMgBr and Cp2Mg, cyclopentadienylthallium is less air sensitive. It is also much less of a reducing agent.

References

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  1. ^ C. Elschenbroich (2006). Organometallics. Wiley-VCH, Weinheim. p. 130. ISBN 3-527-29390-6.
  2. ^ A.J. Nielson; C.E.F. Rickard; J.M. Smith (2007). "Cyclopentadienylthallium (Thallium Cyclopentadienide)". Inorganic Syntheses. Vol. 24. pp. 97–99. doi:10.1002/9780470132555.ch31. ISBN 9780470132555.
  3. ^ Falk Olbrich, Ulrich Behrens "Crystal structure of catena-cyclopentadienylthallium, [Tl(C5H5)]" Zeitschrift für Kristallographie - New Crystal Structures 1997, 212, 47-47.