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Structure of 3‐nitropyrazole in solution and in the solid state
Author(s) -
FocesFoces Concepcion,
LlamasSaiz Antonio L.,
Menéndez Margarita,
Jagerovic Nadine,
Elguero J.
Publication year - 1997
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199708)10:8<637::aid-poc930>3.0.co;2-p
Subject(s) - chemistry , trimer , triclinic crystal system , crystallography , molecule , ring (chemistry) , crystal structure , aqueous solution , ab initio , crystal (programming language) , envelope (radar) , hydrogen bond , protonation , computational chemistry , organic chemistry , ion , telecommunications , radar , dimer , computer science , programming language
The molecular and crystal structure of 3‐nitropyrazole was determined by X‐ray analysis. The triclinic unit cell contains 12 molecules which form four hydrogen‐bonded (N—H···N) trimers. Each trimer comprises of pseudo‐ring in a flattened envelope distorted towards a chair conformation. The crystal packing consists of layers formed by centrosymmetric related trimers joined through C—H···O interactions. Ab initio calculations were performed on 3(5)‐nitro‐ and 4‐nitropyrazole and their corresponding protonated forms up to the MP2/6–31G** level of theory. The origin of the difference in aqueous basicities between both nitropyrazoles is discussed. © 1997 John Wiley & Sons, Ltd.