Cyclopentadienylthallium
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]
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| Names | |
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| IUPAC name
Thallium(I) cyclopentadienide
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| Other names
Thallium cyclopentadienide
(η5-Cyclopentadienyl)thallium | |
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3D model (JSmol)
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| Properties | |
| C5H5Tl | |
| Molar mass | 269.48 g·mol−1 |
| Appearance | Light yellow solid |
| Melting point | 300 °C (572 °F; 573 K) |
| Insoluble | |
| Hazards | |
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| Danger | |
| NFPA 704 (fire diamond) | <imagemap>
File:NFPA 704.svg|80px|alt=NFPA 704 four-colored diamond poly 150 150 300 300 150 450 0 300 Health 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gas poly 300 0 450 150 300 300 150 150 Flammability 0: Will not burn. E.g. water poly 450 150 600 300 450 450 300 300 Instability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogen poly 300 300 450 450 300 600 150 450 Special hazards (white): no code desc none </imagemap> |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation and structure
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
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
- ^ C. Elschenbroich (2006). Organometallics. Wiley-VCH, Weinheim. p. 130. ISBN 3-527-29390-6.
- ^ 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.
- ^ Falk Olbrich, Ulrich Behrens "Crystal structure of catena-cyclopentadienylthallium, [Tl(C5H5)]" Zeitschrift für Kristallographie - New Crystal Structures 1997, 212, 47-47.