X-ray investigations of benzopyran derivatives substituted at position 3

Rybarczyk, A. J.; Olszak, T. A.; Małecka, Magdalena; Nawrot‐Modranka, Jolanta

doi:10.1107/s0108270199004734

Cited by 11 publications

(12 citation statements)

References 3 publications

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“…In the case of p-nitro-and p-brominederivatives (IV and VI), the observed peaks of electron density maxima are fuzzy and shifted towards the N-oxide O1 oxygen atom. Similar pictures of Fourier difference maps in the area of intramolecular hydrogen bonding bridges are known for benzopyrane derivatives [37][38][39][40][41], and they have been treated as evidence of hydrogen bonding strengthening and possible dynamic proton transfer reaction.…”

Section: Intramolecular Hydrogen Bondsmentioning

confidence: 70%

Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds

et al. 2017

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The crystal structures of new N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives are reported. The results of X-ray diffraction showed the existence of intramolecular hydrogen bonding between carboxamide nitrogen donors and N-oxide oxygen acceptors. The use of Quantum Theory of Atoms in Molecules allowed its classification as a strong interaction, with energy about 10 kcal/mol, and of intermediate character between closed shell and shared bonds. Comparison of experimental data and quantum theoretical calculations indicated that a substituent attached to the phenyl ring in the para position influences the strength and geometry of the title hydrogen bonding. Stronger π-electronwithdrawing properties of the higher energy substituent of the intramolecular hydrogen bond are observed. Among other intermolecular contacts in the studied crystals are C-H…O/ C-H…N hydrogen bonds of imidazole carbon atoms and some π…π stacking interactions between aromatic molecular fragments. Their importance in stabilization of the crystal structure was confirmed by the results of Hirshfeld surface analysis.

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Section: Intramolecular Hydrogen Bondsmentioning

confidence: 70%

Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds

et al. 2017

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“…This stacking is accompanied by respective ring slippage equal to 1.481(4) Å and 1.546(4) Å. With regard to the structure of the 3-aminoflavone ligand, the differentiation of C-C bond lengths within the pyrane system is typical, [28][29][30][31][32] …”

Section: Crystal Structure Descriptionmentioning

confidence: 99%

trans-Platinum(ii) complex of 3-aminoflavone – synthesis, X-ray crystal structure and biological activities in vitro

Fabijańska¹,

Studzian

Szmigiero

et al. 2015

Dalton Trans.

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“…The relatively long N-H bond and a large value of N-H…O bond angle in (I) allow one to classify this intramolecular hydrogen bond as a strong one. Moreover, the short N…O distance suggests that it could also be considered as a low-barrier hydrogen bond [35,36] similar to intramolecular hydrogen bonds observed for benzopyrane derivatives [37][38][39]. To elucidate this observation, low-temperature X-ray measurements were undertaken.…”

Section: Intramolecular Hydrogen Bondmentioning

confidence: 99%

Temperature-dependent polymorphism of N-(4-fluorophenyl)-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide: experimental and theoretical studies on intermolecular interactions in the crystal state

et al. 2014

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X-ray analysis of N-(4-fluorophenyl)-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide reveals the temperature-dependent polymorphism associated with the crystallographic symmetry conversion. The observed crystal structure transformation corresponds to a symmetry reduction from I4 1 /a (I) to P4 3 (II) space groups. The phase transition mainly concerns the subtle but clearly noticeable reorganization of molecules in the crystal space, with the structure of individual molecules left almost unchanged. The Hirshfeld surface analysis shows that various intermolecular contacts play an important role in the crystal packing, revealing graphically the differences in spatial arrangements of the molecules in both polymorphs. The N-oxide oxygen atom acts as a formally negatively charged hydrogen bonding acceptor in intramolecular hydrogen bond of N-H…O -type. The combined crystallographic and theoretical DFT methods demonstrate that the observed intramolecular N-oxide N-H…O hydrogen bond should be classified as a very strong charge-assisted and closed-shell non-covalent interaction.

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X-ray investigations of benzopyran derivatives substituted at position 3

Cited by 11 publications

References 3 publications

Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds

Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds

trans-Platinum(ii) complex of 3-aminoflavone – synthesis, X-ray crystal structure and biological activities in vitro

Temperature-dependent polymorphism of N-(4-fluorophenyl)-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide: experimental and theoretical studies on intermolecular interactions in the crystal state

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