Pentacyanocyclopentadiene

Pentacyanocyclopentadiene

Names
IUPAC name 1,3-Cyclopentadiene-1,2,3,4,5-pentacarbonitrile
Identifiers
CAS Registry Number	69239-40-3
ChemSpider	11484097
InChI InChI=1S/C10HN5/c11-1-6-7(2-12)9(4-14)10(5-15)8(6)3-13/h6H Key: SZRONZXSOSCLOK-UHFFFAOYSA-N InChI=1/C10HN5/c11-1-6-7(2-12)9(4-14)10(5-15)8(6)3-13/h6H Key: SZRONZXSOSCLOK-UHFFFAOYAD
Jmol-3D images	Image
SMILES C(#N)C1C(=C(C(=C1C#N)C#N)C#N)C#N
Properties
Molecular formula	C10HN5
Molar mass	191.15 g·mol−1
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Pentacyanocyclopentadiene is a derivative of cyclopentadiene with five cyano groups with the molecular formula C₅H(CN)₅. The corresponding anion, pentacyanocyclopentadienide, is a ligand with the molecular formula C₅(CN)₅⁻. In contrast to other anions based on a C₅ ring unit it binds to metals through the pendant cyano groups rather than the C₅ ring. The anion was first synthesised by Webster in the 1960s^[1] and its conjugate acid much later on.^[2] More recently Wright has discovered its extensive coordination chemistry.^[3][4]

Synthesis

Pentacyanocyclopentadiene is synthesised by coupling carbon disulfide and sodium cyanide in dimethylformamide before oxidation using ammonium persulfate and final purification generates the ammonium pentacyanocyclopentadiene salt. Further reaction with sodium hydride generates NaC₅(CN)₅ which is a starting point for its coordination chemistry with transition metals.

Reactions & Coordination Chemistry

Coupling of sodium pentacyanocyclopentadiene (NaC₅(CN)₅) with transition metal halide salts generates metal complexes containing the C₅(CN)₅⁻ anion.^[3][4] Because the anion binds to metals through the cyanide group it can act as a pentagonal node. Thus it can form fullerene-like structures with large voids containing solvent.^[5][6] This has important implications for gas storage and separation.

References