Imidazolate

Imidazolate (C₃H₃N⁻
₂) is the conjugate base of imidazole. It is a nucleophile and a strong base. The free anion has C_2v symmetry. Imidazole has a pK_a of 14.05,^[1] so the deprotonation of imidazole (C₃H₃N₂H) requires a strong base.

Imidazolate

Names
IUPAC name Imidazolate
Other names Imidazolide
Identifiers
CAS Number	36954-03-7
3D model (JSmol)	Interactive image
ChemSpider	2631931
PubChem CID	4605971 Na salt 12796790 K salt 15977602 Zn salt 129690082 Cu salt
CompTox Dashboard (EPA)	DTXSID201032745
SMILES c1cnc[n-]1
Properties
Chemical formula	C3H3N2−
Molar mass	67.070 g/mol
Acidity (pKa)	14.05[1]
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	67.8 kJ·mol−1 (16.2 kcal·mol−1) Gas phase.[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Occurrence

In the human SOD1 enzyme (N-terminus = blue, C-terminus = red), the copper (orange sphere) and zinc (grey one) are bridged by imidazolate.^[3]

Imidazolate is a common bridging ligand in coordination chemistry. In the zeolitic imidazolate frameworks, the metals are interconnected via imidazolates.^[4][5] In the enzyme superoxide dismutase, imidazolate links copper and zinc centers.