N—H...O and N—H...N interactions in three pyran derivatives. (9th May 2013)

• Record Type: Journal Article
• Authors: Vishnupriya, R.; Suresh, J.; Sivakumar, S.; Kumar, R. Ranjith
• Is Part Of: Acta crystallographica. Volume 69:Part 6(2013:Jun.)
• Page Start: 642
• Page End: 646
• Publication Date: 2013-05-09
• Subjects: Crystallography -- Periodicals; Crystals -- Periodicals; 548.05
• DOI: 10.1107/S0108270113010676
• Languages: English
• ISSNs: 0108-2701

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The three pyran structures 6‐methylamino‐5‐nitro‐2, 4‐diphenyl‐4<italic>H</italic>‐pyran‐3‐carbonitrile, C₁₉H₁₅N₃O₃, (I), 4‐(3‐fluorophenyl)‐6‐methylamino‐5‐nitro‐2‐phenyl‐4<italic>H</italic>‐pyran‐3‐carbonitrile, C₁₉H₁₄FN₃O₃, (II), and 4‐(4‐chlorophenyl)‐6‐methylamino‐5‐nitro‐2‐phenyl‐4<italic>H</italic>‐pyran‐3‐carbonitrile, C₁₉H₁₄ClN₃O₃, (III), differ in the nature of the aryl group at the 4‐position. The heterocyclic ring in all three structures adopts a flattened boat conformation. The dihedral angle between the pseudo‐axial phenyl substituent and the flat part of the pyran ring is 89.97 (1)° in (I), 80.11 (1)° in (II) and 87.77 (1)° in (III). In all three crystal structures, a strong intramolecular N—H...O hydrogen bond links the flat conjugated H—N—C=C—N—O fragment into a six‐membered ring. In (II), molecules are linked into dimeric aggregates by N—H... O(nitro) hydrogen bonds, generating an <italic>R</italic>₂²(12) graph‐set motif. In (III), intermolecular N—H...N and C—H...N hydrogen bonds link the molecules into a linear chain pattern generating <italic>C</italic>(8) and <italic>C</italic>(9) graph‐set motifs, respectively.</p> </abstract>