Sodium cyclopentadienide

In this article, we are going to delve into the fascinating world of Sodium cyclopentadienide. From its origins to its influence on today's society, we will explore all the relevant aspects related to this topic. Over the next few lines, we will analyze its impact in different areas, its evolution over time, as well as its possible implications in the future. We will address both its positive and negative aspects, with the goal of giving the reader a more complete and balanced understanding of Sodium cyclopentadienide. Join us on this tour and discover everything there is to know about this fascinating topic.

"NaCp" redirects here. For other uses, see NACP (disambiguation).
Sodium cyclopentadienide
NaCp synthesized in an inert atmosphere
Names
Preferred IUPAC name
Sodium cyclopentadienide
Other names
Sodium cyclopentadienylide, Cyclopentadienylsodium
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.023.306 Edit this at Wikidata
EC Number
  • 225-636-8
  • InChI=1S/C5H5.Na/c1-2-4-5-3-1;/h1-5H;/q-1;+1 checkY
    Key: OHUVHDUNQKJDKW-UHFFFAOYSA-N checkY
  • InChI=1S/C5H5.Na/c1-2-4-5-3-1;/h1-5H;/q-1;+1
  • Key: OHUVHDUNQKJDKW-UHFFFAOYSA-N
  • .c1ccc1
Properties
C5H5Na
Molar mass 88.085 g·mol−1
Appearance colorless solid
Density 1.113 g/cm3
decomposition
Solubility THF
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa).
checkY verify (what is checkY☒N ?)

Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion.[1] Sodium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities.[2]

Preparation

The first salt of cyclopentadienide to be reported was potassium cyclopentadienide, prepared by Johannes Thiele. In 1901 there was not much interest in the topic.[3]

Sodium cyclopentadienyl is prepared by treating cyclopentadiene with sodium:[4]

2 Na + 2 C5H6 → 2 NaC5H5 + H2

The conversion can be conducted by heating a suspension of molten sodium in dicyclopentadiene.[2] In former times, the sodium was provided in the form of "sodium wire" or "sodium sand", a fine dispersion of sodium prepared by melting sodium in refluxing xylene and rapidly stirring.[5][6] Sodium hydride is a convenient base:[7]

NaH + C5H6 → NaC5H5 + H2

In early work, Grignard reagents were used as bases. With a pKa of 15, cyclopentadiene can be deprotonated by many reagents.

Sodium cyclopentadienide is commercially available as a solution in THF.

Applications

Sodium cyclopentadienide is a common reagent for the preparation of metallocenes. For example, the preparation of ferrocene[5] and zirconocene dichloride:[8]

2 NaC5H5 + FeCl2 → Fe(C5H5)2 + 2 NaCl
ZrCl4(thf)2 + 2 NaCp → (C5H5)2ZrCl2 + 2 NaCl + 2 THF

Sodium cyclopentadienide is also used for the preparation of substituted cyclopentadienyl derivatives such as the ester and formyl derivatives:[9]

NaC5H5 + O=C(OEt)2 → NaC5H4CO2Et + NaOEt

These compounds are used to prepare substituted metallocenes such as 1,1'-ferrocenedicarboxylic acid.[10]

Structure

The nature of NaCp depends strongly on its medium and for the purposes of planning syntheses; the reagent is often represented as a salt Na+
C
5H−
5. Crystalline solvent-free NaCp, which is rarely encountered, is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Na+ centers sandwiched between μ-η5:η5-C5H5 ligands.[11] As a solution in donor solvents, NaCp is highly solvated, especially at the alkali metal as suggested by the isolability of the adduct Na(tmeda)Cp.[12]

In contrast to alkali metal cyclopentadienides, tetrabutylammonium cyclopentadienide (Bu
4N+
C
5H−
5) was found to be supported entirely by ionic bonding and its structure is representative of the structure of the cyclopentadienide anion (C
5H−
5, Cp−) in the solid state. However, the anion deviates somewhat from a planar, regular pentagon, with C–C bond lengths ranging from 138.0 -140.1 pm and C–C–C bond angles ranging from 107.5-108.8°.[13]


See also

References

  1. ^ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSC–IUPAC. ISBN 0-85404-438-8. p. 262. Electronic version.
  2. ^ a b Tarun K. Panda, Michael T. Gamer, Peter W. Roesky "An Improved Synthesis of Sodium and Potassium Cyclopentadienide" Organometallics, 2003, 22, 877–878.doi:10.1021/om0207865
  3. ^ Johannes Thiele (January 1901). "Ueber Abkömmlinge des Cyclopentadiëns". Berichte der Deutschen Chemischen Gesellschaft (in German). 34 (1): 68–71. doi:10.1002/CBER.19010340114. ISSN 0365-9496. Wikidata Q126217369.
  4. ^ Cotton, F. Albert; Wilkinson, Geoffrey (1988), Advanced Inorganic Chemistry (5th ed.), New York: Wiley-Interscience, p. 139, ISBN 0-471-84997-9
  5. ^ a b Wilkinson, Geoffrey (1963). "Ferrocene". Organic Syntheses; Collected Volumes, vol. 4, p. 473.
  6. ^ Partridge, John J.; Chadha, Naresh K.; Uskokovic, Milan R. (1990). "An asymmetric hydroboration of 5-substituted cyclopentadienes: synthesis of methyl (1R,5R)-5-hydroxy-2-cyclopentene-1-acetate". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 7, p. 339.
  7. ^ Girolami, G. S.; Rauchfuss, T. B. & Angelici, R. J. (1999). Synthesis and Technique in Inorganic Chemistry. CA: University Science Books: Mill Valley. ISBN 0935702482.{{cite book}}: CS1 maint: publisher location (link)
  8. ^ Wilkinson, G.; Birmingham, J. G. (1954). "Bis-cyclopentadienyl Compounds of Ti, Zr, V, Nb and Ta". J. Am. Chem. Soc. 76 (17): 4281–84. Bibcode:1954JAChS..76.4281W. doi:10.1021/ja01646a008.
  9. ^ Macomber, D. W.; Hart, W. P.; Rausch, M. D. (1982). "Functionally Substituted Cyclopentadienyl Metal Compounds". Adv. Organomet. Chem. Advances in Organometallic Chemistry. 21: 1–55. doi:10.1016/S0065-3055(08)60377-9. ISBN 9780120311217.
  10. ^ Petrov, Alex R.; Jess, Kristof; Freytag, Matthias; Jones, Peter G.; Tamm, Matthias (2013). "Large-Scale Preparation of 1,1′-Ferrocenedicarboxylic Acid, a Key Compound for the Synthesis of 1,1′-Disubstituted Ferrocene Derivatives". Organometallics. 32 (20): 5946–5954. doi:10.1021/om4004972.
  11. ^ Robert E. Dinnebier; Ulrich Behrens & Falk Olbrich (1997). "Solid State Structures of Cyclopentadienyllithium, -sodium, and -potassium. Determination by High-Resolution Powder Diffraction". Organometallics. 16 (17): 3855–3858. doi:10.1021/om9700122.
  12. ^ Elschenbroich, C. (2006). Organometallics. Wiley-VCH: Weinheim. ISBN 978-3-527-29390-2.
  13. ^ Reetz, Manfred T.; Hütte, Stephan; Goddard, Richard (1995-03-01). "Tetrabutylammonium Salts of 2-Nitropropane, Cyclopentadiene and 9-Ethylfluorene: Crystal Structures and Use in Anionic Polymerization". Zeitschrift für Naturforschung B. 50 (3): 415–422. doi:10.1515/znb-1995-0316. ISSN 1865-7117. S2CID 45791403.