Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7810237 | Journal of Molecular Structure | 2013 | 11 Pages |
Abstract
A single crystal X-ray diffraction and theoretical study has been carried out on mono hydrates of three 2H-pyrazolo[4,3-c]quinolin-3(5H)-one derivatives, namely 6-methyl-2-phenylpyrazolo[4,3-c]quinolin-3-one, 3, 6-methyl-2-(4-chlorophenyl)pyrazolo[4,3-c]quinolin-3-one, 4, and 8-methyl-2-(4-nitrophenyl)pyrazolo[4,3-c]quinolin-3-one, 5. The monohydrates were obtained on recrystallization from moist solvents. While there are three tautomeric forms possible for such pyrazolo[4,3-c]quinolin-3-one molecules, the sole form isolated in the solid [(X)â
(H2O)] (XÂ =Â 3, 4 and 5) compounds was the quinoloid form - the one calculated to be the most stable at the M06-2X/6-311++G(d,p) level of theory. Excellent agreement was found between the calculated and X-ray determined structures. Molecule 5 in [(5)â
(H2O)] is very near planar while both molecules 3 and 4 in their respective hydrates are much less so as a consequence of angles about 24° between the two aromatic rings. In each hydrate, the pyrazolo[4,3-c]quinolin-3-one molecule is bonded to three water molecules and each water molecule is likewise H-bonded to three pyrazolo[4,3-c]quinolin-3-one molecules. While the water molecules are H-bonded to 3 and 4 via the pyridinyl N and 2x the carbonyl O atoms, in [(5)â
(H2O)] the H-bonds are to pyridinyl N, carbonyl O and a nitro O atoms. Calculations indicated that the found arrangement in [(5)â
(H2O)] is more stable than one using the connections as found in [(3)â
(H2O)] and [(4)â
(H2O)]. While each of the hydrates possess strong NHâ¯O and OHâ¯O hydrogen bonds, and weaker CHâ¯Ï and Ïâ¯Ï interactions, the supramolecular arrays are very different.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Vitor F. Ferreira, Katia Z. Leal, Eric B. Lindgren, Mara R.P. de Oliveira, Maria Celia B.V. de Souza, Thatyana R.A. Vasconcelos, James L. Wardell, Solange M.S.V. Wardell, Julliane D. Yoneda,