Abstract:Isomorphous crystals of 5-chloro-7-iodo- and 5,7-dibromo-8-quinolinols have been examined by X-ray analysis. Both compounds crystallize in the monoclinic space group P2⁄a with four formula units in the unit cell. The cell dimensions are: a=16.98; b=4.16; c=14.84 Å, and β=112.0° for 5-chloro-7-iodo-8-quinolinol, and a=16.34, b=4.02, c=15.52 Å, and β=115.6° for 5,7-dibromo-8-quinolinol. The structure of the former, chinoform, has been determined by the Patterson methods from data collected with MoKα radiation on… Show more
“…Only one resonance line is observed in each, at 35.170 MHz for clioquinol and at 34.787 MHz for cloxiquine at 77K. All of the molecules are thus crystallographically equivalent in each of these compounds, which is in agreement with the X-ray data [42–45]. Fig.…”
The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via 35Cl NQR, 1H-17O and 1H-14N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O–H···N hydrogen bonds linking dimers and π–π stacking interactions were described within the QTAIM (quantum theory of atoms in molecules) /DFT (density functional theory) formalism. Both proton donor and acceptor sites in O–H···N bonds were characterized using 1H-17O and 1H-14N NQDR spectroscopies and QTAIM. The possibility of the existence of O–H···H–O dihydrogen bonds was excluded. The weak intermolecular interactions in the crystals of clioquinol and cloxiquine were detected and examined. The results obtained in this work suggest that considerable differences in the NQR parameters for the planar and twisted supramolecular synthons permit differentiation between specific polymorphic forms, and indicate that the more planar supramolecular synthons are accompanied by a greater number of weaker hydrogen bonds linking them and stronger π···π stacking interactions.FigureThe 1H-14N solid effect double resonance spectra and the relief map of the Laplacian of electron density in the OH...N plane for clioquinol and cloxiquine
“…Only one resonance line is observed in each, at 35.170 MHz for clioquinol and at 34.787 MHz for cloxiquine at 77K. All of the molecules are thus crystallographically equivalent in each of these compounds, which is in agreement with the X-ray data [42–45]. Fig.…”
The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via 35Cl NQR, 1H-17O and 1H-14N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O–H···N hydrogen bonds linking dimers and π–π stacking interactions were described within the QTAIM (quantum theory of atoms in molecules) /DFT (density functional theory) formalism. Both proton donor and acceptor sites in O–H···N bonds were characterized using 1H-17O and 1H-14N NQDR spectroscopies and QTAIM. The possibility of the existence of O–H···H–O dihydrogen bonds was excluded. The weak intermolecular interactions in the crystals of clioquinol and cloxiquine were detected and examined. The results obtained in this work suggest that considerable differences in the NQR parameters for the planar and twisted supramolecular synthons permit differentiation between specific polymorphic forms, and indicate that the more planar supramolecular synthons are accompanied by a greater number of weaker hydrogen bonds linking them and stronger π···π stacking interactions.FigureThe 1H-14N solid effect double resonance spectra and the relief map of the Laplacian of electron density in the OH...N plane for clioquinol and cloxiquine
“…The distributions of the aromatic bond lengths in both compounds are in good agreement with that calculated for quinoline (Dewar & Gleicher, 1966), and with those observed in different derivatives of quinoline (Stankovic et al 1976;Kashino & Haisa, 1973;Polyakova et al 1980;Banerjee et al 1984) and other N-heterocyclic compounds like the acridines (Achari & Neidle, 1977;Courseille, Leroy, Hospital & Barbet, 1977). The endocyclic bond angles of the present molecules are also close to the values observed in similar structures (Stankovic et al 1976;Kashino & Haisa, 1973;Prout & Wheeler, 1967;Castellano & Prout, 1971;Banerjee et al 1984). In (I), the C-C1 bond length and the angle ipso to C1 indicate that the CI atom acts as an electron-withdrawing group and has no conjugative effect (Domenicano, Vaciago & Coulson, 1975).…”
Section: -Hydroxyquinoline Derivativessupporting
confidence: 84%
“…This observation indicates conjugation between the benzene ring and the hydroxyl group in (I) (Domenicano et al, 1975). We observe that similar conjugation also occurs in other 8-hydroxyquinoline derivatives having electron-withdrawing substituents at the para positions (Kashino & Haisa, 1973;Stankovic et al 1976;Merrit & Duffin, 1970) and in the metal complexes of 8-hydroxyquinolines (Palenik, 1964;Camerman & Taylor, 1968;Raston, Skelton & White, 1978).…”
“…with rhenium [1] and severalrareearth elements [2,3]). The crystal structure of thetitle compound has been reported earlier, however, without deposition of 3D coordinates [4] or at room temperature lacking discussion of intermolecular forces [5]. Therefore, the crystal structure of thet itle compound was re-determined at 200 Kt oc lose this gap and to allow for comparisons of metrical parameters of the ligand in envisioned coordination compounds.…”
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