lithium cyclopentadienide
{{chembox
|Watchedfields = changed
|verifiedrevid = 418117276
|ImageFile=NaCp-chain-from-xtal-3D-balls-C.png
|OtherNames= lithium cyclopentadienylide, cyclopentadienyllithium, LiCp
|Section1={{Chembox Identifiers
| CASNo=16733-97-4
| CASNo_Ref = {{cascite|correct|CAS}}
| EINECS = 627-659-2
| PubChem=14063469
| StdInChI=1S/C5H5.Li/c1-2-4-5-3-1;/h1-3H,4H2;/q-1;+1
| StdInChIKey = CSOHRTAOCDVTQU-UHFFFAOYSA-N
| SMILES = [Li+].C1C=CC=[C-]1
}}
|Section2={{Chembox Properties
|C=5 | H=5 | Li=1
|Appearance=colorless solid
|Density=1.064 g/cm3
|Solubility=decomposition
|SolubleOther=THF, dimethoxyethane
}}
}}
Lithium cyclopentadienide is an organolithium compound with the formula C5H5Li. The compound is often abbreviated as LiCp, where Cp− is the cyclopentadienide anion. Lithium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities.
Preparation, structure and reactions
Lithium cyclopentadienide is commercially available as a solution in tetrahydrofuran. It is prepared by treating cyclopentadiene with butyllithium:{{cite journal|title=Revealing Coordination Patterns in C5-Cyclic Lithium Organics|author=Reent Michel |author2=Regine Herbst-Irmer |author3=Dietmar Stalke |journal=Organometallics|year=2011|volume=30|issue=16|pages=4379–4386|doi=10.1021/om200471e|url=http://resolver.sub.uni-goettingen.de/purl?gs-1/8945}}
:C5H6 + LiC4H9 → LiC5H5 + C4H10
Because lithium cyclopentadienide is usually handled as a solution, the solvent-free solid is rarely encountered. According to X-ray crystallography, LiCp is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Li+ centers sandwiched between μ-η5:η5-C5H5 ligands.{{cite journal |author1=Robert E. Dinnebier |author2=Ulrich Behrens |author3=Falk Olbrich |name-list-style=amp | title = Solid State Structures of Cyclopentadienyllithium, -sodium, and -potassium. Determination by High-Resolution Powder Diffraction | journal = Organometallics | year = 1997 | volume = 16 |issue=17 | pages = 3855–3858 | doi = 10.1021/om9700122}} In the presence of amines or ethers, LiCp gives adducts, e.g. (η5-Cp)Li(TMEDA). LiCp is a common reagent for the preparation of cyclopentadienyl complexes.
See also
References
{{reflist}}
{{Lithium compounds}}
{{Cyclopentadiene complexes}}
Category:Cyclopentadienyl complexes