Dipotassium cyclooctatetraenide

Dipotassium cyclooctatetraenide

Identifiers
CAS Number	59391-85-4
3D model (Jmol)	Interactive image
ChemSpider	57575621
InChI InChI=1S/C8H8.2K/c1-2-4-6-8-7-5-3-1;;/h1-8H;;/q-2;2*+1/b2-1-,5-3-,8-6-;; Key: JEUFATMWOKTCQC-YGFQESQOSA-N InChI=1/C8H8.2K/c1-2-4-6-8-7-5-3-1;;/h1-8H;;/q-2;2*+1/b2-1-,5-3-,8-6-;; Key: JEUFATMWOKTCQC-YGFQESQOBL
SMILES [cH-]/1/cc\cc/[cH-]/cc1.[K+].[K+]
Properties
Chemical formula	C8H8K2
Appearance	beige solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Dipotassium cyclooctatetraenide, sometimes abbreviated K₂COT, is an organopotassium compound with the formula K₂C₈H₈. It is a brown solid that is used as a precursor to cyclooctatetraenide complexes, such as uranocene (U(C₈H₈)₂). Analogs of K₂C₈H₈ are known with ring substituents, with different alkali metals, and with various complexants.

Ball-and-stick model of COT²⁻

Preparation and structure

Potassium cyclooctatetraenide is formed by the reaction of cyclooctatetraene with potassium metal:

2 K + C₈H₈ → K₂C₈H₈

The reaction entails 2-electron reduction of the polyene and is accompanied by a color change from colorless to brown.^[1]

The structure of K₂(diglyme)C₈H₈ has been characterized by X-ray crystallography of the derivatives with diglyme complexed to the potassium cations. The C₈H₈ unit is planar with an average C-C distance of 1.40 A.^[2]

References

1. ↑ A. L Wayda (1990). "Cyclooctatetraene Lanthanide Complexes. Lu(C₈H₈Cl(thf) and Lu(C₈H₈)[o-C₆H₄CH₂N(CH₃)₂(thf)". Inorganic Syntheses. 27: 150. doi:10.1002/9780470132586.ch28. 
2. ↑ J. H. Noordik, T. E. M. van den Hark, J. J. Mooij and A. A. K. Klaassen (1974). "Dipotassium(I) cyclooctatetraenide-1-methoxy-2-(2-methoxyethoxy)ethane". Acta Crystallogr B. 30 (30): 833–835. doi:10.1107/S0567740874003840.  CS1 maint: Multiple names: authors list (link)