Nine N-aryl-2-chloronicotinamides: supramolecular structures in one, two and three dimensions

Abstract

Structures are reported here for eight further substituted N-aryl-2-chloronicotinamides, 2-ClC(5)H(3)NCONHC(6)H(4)X-4'. When X = H, compound (I) (C(12)H(9)ClN(2)O), the molecules are linked into sheets by N-H...N, C-H...pi(pyridyl) and C-H...pi(arene) hydrogen bonds. For X = CH(3), compound (II) (C(13)H(11)ClN(2)O, triclinic P1 with Z' = 2), the molecules are linked into sheets by N-H...O, C-H...O and C-H...pi(arene) hydrogen bonds. Compound (III), where X = F, crystallizes as a monohydrate (C(12)H(8)ClFN(2)O.H(2)O) and sheets are formed by N-H...O, O-H...O and O-H...N hydrogen bonds and aromatic pi...pi stacking interactions. Crystals of compound (IV), where X = Cl (C(12)H(8)Cl(2)N(2)O, monoclinic P2(1) with Z' = 4) exhibit inversion twinning: the molecules are linked by N-H...O hydrogen bonds into four independent chains, linked in pairs by C-H...pi(arene) hydrogen bonds. When X = Br, compound (V) (C(12)H(8)BrClN(2)O), the molecules are linked into sheets by N-H...O and C-H...N hydrogen bonds, while in compound (VI), where X = I (C(12)H(8)ClIN(2)O), the molecules are linked into a three-dimensional framework by N-H...O and C-H...pi(arene) hydrogen bonds and an iodo...N(pyridyl) interaction. For X = CH(3)O, compound (VII) (C(13)H(11)ClN(2)O(2)), the molecules are linked into chains by a single N-H...O hydrogen bond. Compound (VIII) (C(13)H(8)ClN(3)O, triclinic P1 with Z' = 2), where X = CN, forms a complex three-dimensional framework by N-H...N, C-H...N and C-H...O hydrogen bonds and two independent aromatic pi...pi stacking interactions.

The crystal structure of the Schiff base (E)-2,6-diisopropyl-N-(pyridin-3-yl-methylene)aniline, C18H22N2

“…the figure). The C6-N2 imine bond length of 1.2704(11) Å, is perfectly within the expected range and is close to those of similar compounds reported in literature [4][5][6][7].…”

Patterns of hydrogen bonding in mono- and di-substituted N-arylpyrazinecarboxamides

“…Otherwise, however, the amido N-H bond plays no role in the intermolecular hydrogen bonding, almost as if the presence of the intramolecular N-HÁ Á ÁN interaction was in most cases sufficient to completely satisfy the hydrogenbonding requirements of this N-H unit. Hence, none of the structures discussed here contain an intermolecular N-HÁ Á ÁO hydrogen bond having the amido O atom as the acceptor, so the chainforming C(4) motif, characteristic of carboxamides of this general type (Kashino et al, 1979;Bowes et al, 2003;Glidewell et al, 2003;Kumar et al, 2004;Garden et al, 2005;Cuffini et al, 2006; and of sulfonamides in general (Vorontsova, 1966;Cotton & Stokely, 1970;Klug, 1970;Brink & Mattes, 1986;Lightfoot et al, 1993; research papers The molecular structures of representative compounds selected to show the atom-labelling schemes and the different molecular conformations: (a) type 1 molecule in the 2-methylphenyl compound (II); (b) type 2 molecule in the 3-methylphenyl compound (III); (c) independent molecular components in the monohydrate of the 3-methoxyphenyl compound (XV); (d) molecule of the 2,6-difluorophenyl compound (XXI). In all cases the displacement ellipsoids are drawn at the 30% probability level.…”

“…Accordingly, we have in our more recent studies attempted to avoid the possible presence of this unpredictable iodoÁ Á Ánitro interaction. These studies have included those of two series of substituted 2-chloro-N-arylnicotinamides, one of them, series (H) (Cuffini et al, 2006), was designed to investigate the effects of changing the identity of a single substituent as a fixed position, while in the second series (J) (de Souza et al, 2005), a common substituent is located at three different positions. In series (H) the supramolecular aggregation is dominated by N-HÁ Á ÁO C hydrogen bonds forming C(4) or C 2 2 ð8Þ (Bernstein et al, 1995) chains when R = Me, Cl, Br, I or OMe, although the methyl and chloro derivatives are not isostructural, but when R = H or CN the dominant intermolecular interactions are N-HÁ Á ÁN(pyridyl) hydrogen bonds.…”

Three isomeric 1-(2-chloronicotinoyl)-2-(nitrophenyl)hydrazines, including three polymorphs of 1-(2-chloronicotinoyl)-2-(2-nitrophenyl)hydrazine: hydrogen-bonded supramolecular structures in two and three dimensions

“…Here we report the molecular and supramolecular structures of three isomeric 1-(2-chloronicotinoyl)-2-(nitrophenyl)hydrazines, (I)-(III), whose molecular constitutions differ only in the location of the nitro group within the nitrophenyl ring (see scheme below); in addition, compound (I), 1-(2-chloronicotinoyl)-2-(2-nitrophenyl)hydrazine, has been identified in three polymorphic forms, denoted (Ia), (Ib) and (Ic), crystallizing in space groups Cc, P2 1 and Pbcn, respectively. This work is a direct extension of our recent studies on the analogous isomeric 2-chloro-N-(nitrophenyl)nicotinamides (IV)-(VI) (de Souza et al, 2005) and on a series of 4-substituted N-aryl-2-chloronicotinamides (VII) (Cuffini et al, 2006), and it describes significant changes in hydrogen bonding, and hence in the overall supramolecular structures, in a series of three geometric isomers, one of which occurs in three polymorphic forms.…”