imidazolate
{{Short description|Ion}}
{{Chembox
| ImageFile = Structure of the imidazolate anion.png
| ImageSize = 130
| ImageAlt =
| IUPACName = Imidazolate
| OtherNames = Imidazolide
| Section1 = {{Chembox Identifiers
| CASNo = 36954-03-7
| PubChem1 = 4605971
| PubChem1_Comment = Na salt
| PubChem2 = 12796790
| PubChem2_Comment = K salt
| PubChem3 = 15977602
| PubChem3_Comment = Zn salt
| PubChem4 = 129690082
| PubChem4_Comment = Cu salt
| ChemSpiderID = 2631931
| SMILES = c1cnc[n-]1
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| Section2 = {{Chembox Properties
| Formula = C3H3N2−
| MolarMass = 67.070 g/mol
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
| Solubility =
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| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
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| Section4 = {{Chembox Thermochemistry
| HeatCapacity =
| Entropy =
| DeltaHf = 67.8 kJ·mol−1 (16.2 kcal·mol−1) Gas phase.{{cite journal|last1=Gutowski|first1=Keith E.|last2=Rogers|first2=Robin D.|last3=Dixon|first3=David A.|title=Accurate Thermochemical Properties for Energetic Materials Applications. II. Heats of Formation of Imidazolium-, 1,2,4-Triazolium-, and Tetrazolium-Based Energetic Salts from Isodesmic and Lattice Energy Calculations|journal=The Journal of Physical Chemistry B|date=May 2007|volume=111|issue=18|pages=4788–4800|doi=10.1021/jp066420d|pmid=17388432}}
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Imidazolate (C3H3N{{su|b=2|p=−}}) is the conjugate base of imidazole. It is a nucleophile and a strong base. The free anion has C2v symmetry. Imidazole has a pKa of 14.05, so the deprotonation of imidazole (C3H3N2H) requires a strong base.
Occurrence
File:2c9v CuZn rib n site.png = blue, C-terminus = red), the copper (orange sphere) and zinc (grey one) are bridged by imidazolate.{{PDB|3CQQ}}; {{cite journal | vauthors = Cao X, Antonyuk SV, Seetharaman SV, Whitson LJ, Taylor AB, Holloway SP, Strange RW, Doucette PA, Valentine JS, Tiwari A, Hayward LJ, Padua S, Cohlberg JA, Hasnain SS, Hart PJ | title = Structures of the G85R variant of SOD1 in familial amyotrophic lateral sclerosis | journal = J. Biol. Chem. | volume = 283 | issue = 23 | pages = 16169–77 |date=June 2008 | pmid = 18378676| doi = 10.1074/jbc.M801522200 | pmc = 2414278 | doi-access = free }}]]
Imidazolate is a common bridging ligand in coordination chemistry. In the zeolitic imidazolate frameworks, the metals are interconnected via imidazolates.Phan, A.; Doonan, C. J.; Uribe-Romo, F. J.; Knobler, C. B.; O'Keeffe, M.; Yaghi, O. M. "Synthesis, Structure, and Carbon Dioxide Capture Properties of Zeolitic Imidazolate Frameworks" Acc. Chem. Res. 2010, 43, 58-67. {{doi|10.1021/ar900116g}}Zhang, J.-P.; Zhang, Y.-B.; Lin, J.-B.; Chen, X.-M., "Metal Azolate Frameworks: From Crystal Engineering to Functional Materials", Chem. Rev. 2012, vol. 112, pp. 1001-1033. {{doi|10.1021/cr200139g}} In the enzyme superoxide dismutase, imidazolate links copper and zinc centers.
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