research communications
A 2:1 N,N′-bis(pyridin-4-ylmethyl)ethanediamide: and Hirshfeld surface analysis
of 2-methylbenzoic acid andaDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, bDepartment of Physics, Bhavan's Sheth R. A. College of Science, Ahmedabad, Gujarat 380 001, India, and cCentre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia
*Correspondence e-mail: edwardt@sunway.edu.my
The 8H8O2·C14H14N4O2, comprises an acid molecule in a general position and half a diamide molecule, the latter being located about a centre of inversion. In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached [dihedral angle = 28.51 (8)°] and the carbonyl O atom and methyl group lie approximately to the same side of the molecule [hydroxy-O—C—C—C(H) torsion angle = −27.92 (17)°]. In the diamide, the central C4N2O2 core is almost planar (r.m.s. deviation = 0.031 Å), and the pyridyl rings are perpendicular, lying to either side of the central plane [central residue/pyridyl dihedral angle = 88.60 (5)°]. In the molecular packing, three-molecule aggregates are formed via hydroxy-O—H⋯N(pyridyl) hydrogen bonds. These are connected into a supramolecular layer parallel to (12) via amide-N—H⋯O(carbonyl) hydrogen bonds, as well as methylene-C—H⋯O(amide) interactions. Significant π–π interactions occur between benzene/benzene, pyridyl/benzene and pyridyl/pyridyl rings within and between layers to consolidate the three-dimensional packing.
of the title 2:1 2CKeywords: crystal structure; co-crystal; hydrogen bonding; carboxylic acid; diamide; Hirshfeld surface analysis.
CCDC reference: 1453604
1. Chemical context
Multi-component crystals, incorporating co-crystals, salts and etc. (Aakeröy, 2015; Tiekink, 2012). Arguably, the areas attracting most interest in this context are the applications of multi-component crystals in the pharmaceutical industry (Duggirala et al., 2016). Controlled/designed crystallization of multi-component crystals requires reliable synthon formation between the various components and that, of course, is the challenge of crystal engineering, let alone engineering small aggregates within crystals (Tiekink, 2014).
salts, attract continuing interest for a wide variety of applications as this technology may be employed, for example, to provide additives to promote the growth of crystals, to stabilize unusual and unstable coformers, to generate new luminescent materials, to separate enantiomers, to facilitate determination where the molecule of concern does not have a significant anomalous scatterer,Systematic work on synthon propensities in multi-component crystals have revealed that carboxylic acids have a great likelihood of forming hydroxy-O—H⋯N hydrogen bonds when co-crystallized with molecules with pyridyl residues (Shattock et al., 2008). A plausible explanation for this reliability is the formation of a supporting carbonyl-O⋯H interaction involving the hydrogen atom adjacent to the pyridyl-nitrogen atom. Indeed, in the absence of competing hydrogen-bonding functionality, the resulting seven-membered {⋯HOCO⋯HCN} heterosynthon is formed in more than 98% of relevant crystal structures (Shattock et al., 2008). Recent systematic work in this phenomenon relates to molecules shown in Scheme 1, where isomeric molecules with two pyridyl rings separated by a diamide residue have been co-crystallized with various carboxylic acids (Arman, Miller et al., 2012; Arman et al., 2013, Syed et al., 2016; Jotani et al., 2016). As a continuation of these studies, the title 2:1 was isolated and characterized crystallographically and by Hirshfeld surface analysis.
2. Structural commentary
The title , was formed from the 1:1 co-crystallization of 2-methylbenzoic acid (hereafter, the acid) and N,N′-bis(pyridin-4-ylmethyl)ethanediamide (hereafter, the diamide) conducted in ethanol solution. The comprises a full acid molecule in a general position and half a diamide molecule, located about a centre of inversion, so the is formulated as a 2:1 acid:diamide co-crystal.
Fig. 1In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached with the O3—C8—C9—C10 torsion angle being 150.23 (14)°, and, to a first approximation, with the carbonyl-O3 atom and methyl group lying to the same side of the molecule as indicated in the O2—C8—C9—C10 torsion angle of −27.92 (17)°. The structure of the parent acid and several co-crystals featuring coformers shown in Scheme 2 are available for comparison; data are collected in Table 1. The common feature of all structures is the relative orientation of the carbonyl-O and methyl groups. Twists in the acid molecules vary from almost co-planar to the situation found in the title with an even split of conformations amongst the six known structures.
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In the centrosymmetric diamide, the central C4N2O2 core is essentially planar with an r.m.s. deviation (O1, N2, C6, C7 and symmetry equivalents) = 0.031 Å. This arrangement facilitates the formation of an intramolecular amide-N—H⋯O(amide) hydrogen bond, Table 2. The pyridyl rings occupy positions on opposite sides of the central residue and project almost prime to this with the central residue/pyridyl dihedral angle being 88.60 (5)°. The aforementioned structural features match literature precedents, i.e. the two polymorphic forms of the parent diamide and the diamide in co-crystals with carboxylic acids and in a salt with a carboxylate, Table 3. Finally, the central C—C bond length, considered long for a Csp2—Csp2 bond (Spek, 2009), matches the structural data included in Table 3; see Scheme 3 for chemical diagrams of coformers.
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3. Supramolecular features
The molecular packing of the title . The acid is connected to the diamide via hydroxy-O—H⋯N(pyridyl) hydrogen bonds to form a three-molecule aggregate, Fig. 2a. The interacting residues are not co-planar with the dihedral angle between the pyridyl and three CO2 groups being 25.67 (8)° so that the carbonyl-O3⋯H3 distance is 2.60 Å. This suggests only a minor role for the putative seven-membered heterosynthon {⋯OCOH⋯NCH} mentioned in the Chemical context and is consistent with the significant hydrogen-bonding interaction involving the carbonyl-O3 atom to another residue. Indeed, the three-molecule aggregates are connected into a supramolecular layer parallel to (12) via amide-N—H⋯O(carbonyl) hydrogen bonds as well as methylene-C—H⋯O(amide) interactions, Fig. 2b. Within layers, π–π interactions occur between pyridyl rings, and between layers additional π–π interactions occur between pyridyl/benzene and benzene/benzene rings to consolidate the three-dimensional packing, Table 4 and Fig. 2c. Globally, the packing may be described as comprising alternating layers of aromatic rings and non-aromatic residues.
is dominated by hydrogen bonding, detailed in Table 2
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4. Analysis of the Hirshfeld surfaces
Crystal Explorer 3.1 (Wolff et al., 2012) was used to generate Hirshfeld surfaces mapped over dnorm, de, electrostatic potential, shape-index and curvedness for the title 2:1 The electrostatic potentials were calculated using TONTO (Spackman et al., 2008; Jayatilaka et al., 2005) integrated with Crystal Explorer, using the experimentally determined geometry as the input. Further, the electrostatic potentials were mapped on Hirshfeld surfaces using the STO-3G basis set at Hartree–Fock theory over a range ±0.15 au. The contact distances di and de from the Hirshfeld surface to the nearest atom inside and outside, respectively, enabled the analysis of the intermolecular interactions through the mapping of dnorm. The combination of di and de in the form of a two-dimensional fingerprint plot (Rohl et al., 2008) provides a summary of the intermolecular contacts.
The strong hydroxy-O—H⋯N(pyridyl) and amide-N—H⋯O(carbonyl) interactions between the acid and diamide molecules are visualized as bright-red spots at the respective donor and acceptor atoms on the Hirshfeld surfaces mapped over dnorm, and labelled as 1 and 2 in Fig. 3. The intermolecular methylene-C—H⋯O(amide) interactions appears as faint-red spots in Fig. 3b, marked with a `3'. The immediate environment about each molecule highlighting close contacts to the Hirshfeld surface by neighbouring molecules is shown in Fig. 4. The full fingerprint (FP) plots showing various crystal packing interactions in the acid, diamide and 2:1 are shown in Fig. 5; the contributions from various contacts are listed in Table 5.
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The prominent long spike at de + di ∼1.8 Å in the upper left (donor) region for the FP plot of the acid corresponds to H⋯N contacts and the spike at the same distance in the lower right (acceptor) region of the FP plot for the diamide are the result of hydroxy-O—H⋯N(pyridyl) interactions, Fig. 5a and b, respectively. However, these spikes are not apparent in the overall FP for the 2:1 as they no longer contribute to the surface of the resultant aggregate, Fig. 5c. Pairs of somewhat blunted spikes corresponding to N⋯H/H⋯N contacts at de + di ∼ 2.9 Å result from amide-N—H⋯O(carbonyl) interactions between the acid and diamide molecules are evident in the overall FP, Fig. 5c.
The O⋯H/H⋯O contacts, which make a significant contribution to the molecular packing, show different characteristic features in the respective delineated FP plots of the acid and diamide. For the acid, Fig. 5a, a long prominent spike at de + di ∼ 2.5 Å in the acceptor region corresponds to a 6.6% contribution from H⋯O contacts to the Hirshfeld surface, and a short spike at de + di ∼ 2.15 Å in the donor region with a 14.0% contribution. The reverse situation is observed for the diamide molecule wherein the FP plot, Fig. 5b, contains a long prominent spike in the donor region and the short spike in the acceptor at the same de + di distance, and with 10.7 and 14.9% contributions from O⋯H and H⋯O contacts, respectively.
FP plots for the a–e, respectively. The H⋯H contacts appear as asymmetrically scattered points covering a large region of the FP plot with a single broad peak at de = di ∼ 1.2 Å for each of the constituents, with percentage contributions of 48.7 and 45.7% for the acid and diamide molecules, respectively. The overall 49.9% contribution to Hirshfeld surface of the results in nearly symmetric through the superimposition of individual fingerprint plots, Fig. 6a.
delineated into H⋯H, O⋯H/H⋯O, C⋯H/H⋯C, N⋯H/H⋯N and C⋯C are shown in Fig. 6The FP plot for O⋯H/H⋯O contacts, Fig. 6b, has two pairs of spikes superimposed in the (de, di) region with minimum de + di distances ∼ 2.2 and 2.5 Å. These correspond to a 21.3% contribution to the Hirshfeld surface, and reflect the presence of intermolecular N—H⋯O and C—H⋯O interactions, identified with labels 1 and 2 in Fig. 6b. The 15.9% contribution from the C⋯H/H⋯C contacts to the Hirshfeld surface results in a symmetric pair of wings, Fig. 6c. The FP plot corresponding to C⋯C contacts, Fig. 6e, in the (de, di) region between 1.7 to 2.2 Å appears as the two distinct, overlapping triangles identified with red and yellow boundaries in Fig. 6e, and shows two types of π–π stacking interactions: one between dissimilar rings (pyridyl and benzene) and the other between symmetry-related rings (benzene and benzene, and pyridyl and pyridyl). The presence of these π–π stacking interactions is also indicated by the appearance of red and blue triangles on the shape-indexed surfaces identified with arrows in the images of Fig. 7, and in the flat regions on the Hirshfeld surfaces mapped with curvedness in Fig. 8.
The intermolecular interactions were further assessed by using the enrichment ratio, ER (Jelsch et al., 2014). This is a relatively new descriptor and is based on Hirshfeld surface analysis. The ER for the together with those for the acid and diamide molecules are listed in Table 6. The largest contribution to the Hirshfeld surfaces are from H⋯H contacts, Table 5, and their respective ER values are close to unity. This shows that the contribution from dispersive forces are significant in the molecule packing of the title 2:1 in contrast to that observed in a related, recently published structure, namely, the salt [2-({[(pyridin-1-ium-2-ylmethyl)carbamoyl]formamido}methyl)-pyridin-1-ium][3,5-dicarboxybenzoate], i.e. containing the diprotonated form of the isomeric 2-pyridyl-containing diamide (Syed et al., 2016). In the latter, O⋯H/H⋯O contacts make the greatest contribution to the crystal packing. It is the presence of different substituents in the benzene ring in the acid molecule in the i.e. methyl, as opposed to carboxylic acid/carboxylate groups in the salt, that provides an explanation for this difference. The ER value for O⋯H/H⋯O contacts, i.e. 1.30, shows the propensity to form hydroxy-O—H⋯N(pyridyl) and amide-N—H⋯O(carbonyl) hydrogen bonds as well as methylene-C—H⋯O(amide) interactions. The formation of extensive π–π interactions is reflected in the relatively high ER values corresponding/related to C⋯C contacts, Table 6. The absence of C—H⋯π and related interactions is reflected in low ER values, i.e. < 0.8. Conversely, the N⋯H/H⋯N contacts in a crystal having ER values equal to greater than or equal to unity for the acid/diamide molecules reduces to 0.84 in the 2:1 indicating a reduced likelihood of formation once the is stabilized by other interactions. The enrichment ratios for other contacts are of low significance as they are derived from less important interactions which have small contributions to Hirshfeld surfaces.
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5. Database survey
As mentioned in the Chemical context, the diamide in the title 2:1 and isomeric forms have attracted considerable interest in the crystal engineering community no doubt owing to the variable functional groups and conformational flexibility. Indeed, the diamide in the title featured in early studies of halogen I⋯N halogen bonding (Goroff et al., 2005). Over and above these investigations, the role of the diamide in coordination chemistry has also been studied. Bidentate bridging is the prominent coordination mode observed in both neutral, e.g. [HgI2(diamide)]n (Zeng et al., 2008) and charged, e.g. polymeric [Ag(diamide)NO3]n (Schauer et al., 1998) and oligiomeric {[Ph2PCH2PPh2Au2(diamide)]2(ClO4)4(EtOEt)4} (Tzeng et al., 2006), species.
6. Synthesis and crystallization
The diamide (0.2 g), prepared in accord with the literature procedure (Schauer et al., 1997), in ethanol (10 ml) was added to a ethanol solution (10 ml) of 2-methylbenzoic acid (Merck, 0.1 g). The mixture was stirred for 1 h at room temperature after which a white precipitate was deposited. The solution was filtered by vacuum suction, and the filtrate was then left to stand under ambient conditions, yielding colourless prisms after 2 weeks.
7. Refinement
Crystal data, data collection and structure . The carbon-bound H-atoms were placed in calculated positions (C—H = 0.95–0.99 Å) and were included in the in the riding-model approximation, with Uiso(H) set to 1.2Ueq(C). The oxygen- and nitrogen-bound H-atoms were located in a difference Fourier map but were refined with distance restraints of O—H = 0.84±0.01 Å and N—H = 0.88±0.01 Å, and with Uiso(H) set to 1.5Ueq(O) and 1.2Ueq(N).
details are summarized in Table 7
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Supporting information
CCDC reference: 1453604
10.1107/S2056989016002735/hb7566sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S2056989016002735/hb7566Isup2.hkl
Supporting information file. DOI: 10.1107/S2056989016002735/hb7566Isup3.cml
Multi-component crystals, incorporating co-crystals, salts and
salts, attract continuing interest for a wide variety of applications as this technology may be employed, for example, to provide additives to promote the growth of crystals, to stabilize unusual and unstable coformers, to generate new luminescent materials, to separate enantiomers, to facilitate determination where the molecule of concern does not have a significant anomalous scatterer, etc (Aakeröy, 2015; Tiekink, 2012). Arguably, the area attracting most interest in this context is the applications of multi-component crystals in the pharmaceutical industry (Duggirala et al., 2016). Controlled/designed crystallization of multi-component crystals requires reliable synthon formation between the various components and that, of course, is the challenge of crystal engineering, let alone engineering small aggregates within crystals (Tiekink, 2014).Systematic work on synthon propensities in multi-component crystals have revealed that carboxylic acids have a great likelihood of forming hydroxy-O—H···N hydrogen bonds when co-crystallized with molecules with pyridyl residues (Shattock et al., 2008). A plausible explanation for this reliability is the formation of a supporting carbonyl-O···H interaction involving the hydrogen atom adjacent to the pyridyl-nitrogen atom. Indeed, in the absence of competing hydrogen-bonding functionality, the resulting seven-membered {···HOCO···HCN} heterosynthon is formed in more than 98% of relevant crystal structures (Shattock et al., 2008). Recent systematic work in this phenomenon relates to molecules shown in Scheme 1, where isomeric molecules with two pyridyl rings separated by a diamide residue have been co-crystallized with various carboxylic acids (Arman, Miller et al., 2012; Arman et al., 2013, Syed et al., 2016; Jotani et al., 2016). As a continuation of these studies, the title 2:1
was isolated and characterized crystallographically and by Hirshfeld surface analysis.The title
Fig. 1, was formed from the 1:1 co-crystallization of 2-methylbenzoic acid and N,N'-bis(pyridin-4-ylmethyl)ethanediamide (hereafter, the diamide) conducted in ethanol solution. The comprises a full acid molecule in a general position and half a diamide molecule, located about a centre of inversion, so the is formulated as a 2:1 acid:diamide co-crystal.In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached with the O3—C8—C9—C10 torsion angle being 150.23 (14)°, and, to a first approximation, with the carbonyl-O3 atom and methyl group lying to the same side of the molecule as indicated in the hydroxy-O2—C8—C9—C10(H) torsion angle of -27.92 (17)°. The structure of the parent acid and several co-crystals featuring coformers shown in Scheme 2 are available for comparison; data are collected in Table 1. The common feature of all structures is the relative orientation of the carbonyl-O and methyl groups. Twists in the acid molecules vary from almost co-planar to the situation found in the title
with an even split of conformations amongst the six known structures.In the centrosymmetric diamide, the central C4N2O2 core is essentially planar with an r.m.s. deviation (O1, N2, C6, C7 and symmetry equivalents) = 0.031 Å. This arrangement facilitates the formation of an intramolecular amide-N—H···O(amide) hydrogen bond, Table 2. The pyridyl rings occupy positions on opposite sides of the central residue and project almost prime to this with the central residue/pyridyl dihedral angle being 88.60 (5)°. The aforementioned structural features match literature precedents, i.e. the two polymorphic forms of the parent diamide and the diamide in co-crystals with carboxylic acids and in a salt with a carboxylate, Table 3. Finally, the central C—C bond length, considered long for a Csp2—Csp2 bond (Spek, 2009), matches the structural data included in Table 3; see Scheme 3 for chemical diagrams of coformers.
The molecular packing of the title 2) via amide-N—H···O(carbonyl) hydrogen bonds as well as methylene-C—H···O(amide) interactions, Fig. 2b. Within layers, π–π interactions occur between pyridyl rings, and between layers additional π–π interactions occur between pyridyl/benzene and benzene/benzene rings to consolidate the three-dimensional packing, Table 4 and Fig. 2c. Globally, the packing may be described as comprising alternating layers of aromatic rings and non-aromatic residues.
is dominated by hydrogen bonding, detailed in Table 2. The carboxylic acid is connected to the diamide via hydroxy-O—H···N(pyridyl) hydrogen bonds to form a three-molecule aggregate, Fig. 2a. The interacting residues are not co-planar with the dihedral angle between the pyridyl and three CO2 groups being 25.67 (8)° so that the carbonyl-O3···H3 distance is 2.60 Å. This suggests only a minor role for the putative seven-membered heterosynthon {···OCOH···NCH} mentioned in the Chemical context and is consistent with the significant hydrogen-bonding interaction involving the carbonyl-O3 atom to another residue. Indeed, the three-molecule aggregates are connected into a supramolecular layer parallel to (12Crystal Explorer 3.1 (Wolff et al., 2012) was used to generate Hirshfeld surfaces mapped over dnorm, de, electrostatic potential, shape-index and curvedness for the title 2:1
The electrostatic potentials were calculated using TONTO (Spackman et al., 2008; Jayatilaka et al., 2005) integrated with Crystal Explorer, using the experimentally determined geometry as the input. Further, the electrostatic potentials were mapped on Hirshfeld surfaces using the STO-3G basis set at Hartree–Fock theory over a range ±0.15 au. The contact distances di and de from the Hirshfeld surface to the nearest atom inside and outside, respectively, enabled the analysis of the intermolecular interactions through the mapping of dnorm. The combination of di and de in the form of a two-dimensional fingerprint plot (Rohl et al., 2008) provides a summary of the intermolecular contacts.The strong hydroxy-O—H···N(pyridyl) and amide-N—H···O(carbonyl) interactions between the acid and diamide molecules are visualized as bright-red spots at the respective donor and acceptor atoms on the Hirshfeld surfaces mapped over dnorm, and labelled as 1 and 2 in Fig. 3. The intermolecular methylene-C—H···O(amide) interactions appears as faint-red spots in Fig. 3b, marked with a `3'. The immediate environment about each molecule highlighting close contacts to the Hirshfeld surface by neighbouring molecules is shown in Fig. 4. The full fingerprint (FP) plots showing various crystal packing interactions in the acid, diamide and 2:1
are shown in Fig. 5; the contributions from various contacts are listed in Table 5.The prominent long spike at de + di ~1.8 Å in the upper left (donor) region for the FP plot of the acid corresponds to H···N contacts and the spike at the same distance in the lower right (acceptor) region of the FP plot for the diamide are the result of hydroxy-O—H···N(pyridyl) interactions, Figs 5a and b, respectively. However, these spikes are not apparent in the overall FP for the 2:1 as they no longer contribute to the surface of the resultant aggregate, Fig. 5c. Pairs of somewhat blunted spikes corresponding to N···H/H···N contacts at de + di ~2.9 Å result from amide-N—H···O(carbonyl) interactions between the acid and diamide molecules are evident in the overall FP, Fig. 5c.
The O···H/H···O contacts, which make a significant contribution to the molecular packing, show different characteristic features in the respective delineated FP plots of the acid and diamide. For the acid, Fig. 5a, a long prominent spike at de + di ~2.5 Å in the acceptor region corresponds to a 6.6% contribution from H···O contacts to the Hirshfeld surface, and a short spike at de + di ~2.15 Å in the donor region with a 14.0% contribution from O···H contacts. The reverse situation is observed for the diamide molecule wherein the FP plot, Fig. 5b, contains a long prominent spike in the donor region and the short spike in the acceptor at the same de + di distance, and with 10.7 and 14.9% contributions from O···H and H···O contacts, respectively.
FP plots for the ~1.2 Å for each of the constituents, with percentage contributions of 48.7 and 45.2% for the acid and diamide molecules, respectively. The overall 49.9% contribution to Hirshfeld surface of the results in nearly symmetric through the superimposition of individual fingerprint plots, Fig. 6a.
delineated into H···H, O···H/H···O, C···H/H···C, N···H/H···N and C···C are shown in Figs 6a–e, respectively. The H···H contacts appear as asymmetrically scattered points covering a large region of the FP plot with a single broad peak at de = diThe FP plot for O···H/H···O contacts, Fig. 6b, has two pairs of spikes superimposed in the (de, di) region with minimum de + di distances ~2.15 and 2.5 Å. These correspond to a 21.3% contribution to the Hirshfeld surface, and reflect the presence of intermolecular N—H···O and C—H···O interactions, identified with labels 1 and 2 in Fig. 6b. The 15.9 % contribution from the C···H/H···C contacts to the Hirshfeld surface results in a symmetric pair of wings, Fig. 6c. The FP plot corresponding to C···C contacts, Fig. 6e, in the (de, di ) region between 1.7 to 2.2 Å appears as the two distinct, overlapping triangles identified with red and yellow boundaries in Fig. 6e, and shows two types of π–π stacking interactions: one between dissimilar rings (pyridyl and benzene) and the other between symmetry-related rings (benzene and benzene, and pyridyl and pyridyl). The presence of these π–π stacking interactions is also indicated by the appearance of red and blue triangles on the shape-indexed surfaces identified with arrows in the images of Fig. 7, and in the flat regions on the Hirshfeld surfaces mapped with curvedness in Fig. 8.
The intermolecular interactions were further assessed by using the enrichment ratio, ER (Jelsch et al., 2014). This is a relatively new descriptor and is based on Hirshfeld surface analysis. The ER for the π–π interactions is reflected in the relatively high ER values, Table 6. The absence of C—H···π and related interactions is reflected in low ER values, i. e. < 0.8. The N···H/H···N contacts in a crystal having ER values equal to greater than or equal to unity for the acid/diamide molecules reduces to 0.84 in the 2:1 co-crystals, indicating a reduced likelihood of formation once the is stabilized by other interactions. The enrichment ratios for other contacts are of low significance as they are derived from less important interactions which have small contributions to Hirshfeld surfaces.
together with those for the acid and diamide molecules are listed in Table 6. The largest contribution to the Hirshfeld surfaces are from H···H contacts, Table 5, and their respective ER values are close to unity. This shows that the contribution from dispersive forces are significant in the molecule packing of the title 2:1 in contrast to that observed in a related, recently published structure, namely, the salt [2-({[(pyridin-1-ium-2-ylmethyl)carbamoyl]formamido}methyl)-pyridin-1-ium][3,5-dicarboxybenzoate], i.e. containing the diprotonated form of the isomeric 2-pyridyl-containing diamide (Syed et al., 2016). In the latter, O···H/H···O contacts make the greatest contribution to the crystal packing. It is the presence of different substituents in the benzene ring in the acid molecule in the i.e. methyl, as opposed to carboxylic acid/carboxylate groups in the salt, that provides an explanation for this difference. The ER value for O···H/H···O contacts, i.e. 1.30, shows the propensity to form hydroxy-O—H···N(pyridyl) and amide-N—H···O(carbonyl) hydrogen bonds as well as methylene-C—H···O(amide) interactions. The formation of extensiveAs mentioned in the Chemical context, the diamide in the title 2:1
and isomeric forms have attracted considerable interest in the crystal engineering community no doubt owing to the variable functional groups and conformational flexibility. Indeed, the diamide in the title featured in early studies of halogen I···N halogen bonding (Goroff et al., 2005). Over and above these investigations, the role of the diamide in coordination chemistry has also been studied. Bidentate bridging is the prominent coordination mode observed in both neutral, e.g. [HgI2(diamide)]n (Zeng et al., 2008) and charged, e.g. polymeric [Ag(diamide)NO3]n (Schauer et al., 1998) and oligiomeric {[Ph2PCH2PPh2Au2(diamide)]2(ClO4)4(EtOEt)4} (Tzeng et al., 2006), species.The diamide (0.2 g), prepared in accord with the literature procedure (Schauer et al., 1997), in ethanol (10 ml) was added to a ethanol solution (10 ml) of 2-methylbenzoic acid (Merck, 0.1 g). The mixture was stirred for 1 h at room temperature after which a white precipitate was deposited. The solution was filtered by vacuum suction, and the filtrate was then left to stand under ambient conditions, yielding colourless prisms after 2 weeks.
Crystal data, data collection and structure
details are summarized in Table 7. The carbon-bound H-atoms were placed in calculated positions (C—H = 0.95–0.99 Å) and were included in the in the riding-model approximation, with Uiso(H) set to 1.2Ueq(C). The oxygen- and nitrogen-bound H-atoms were located in a difference Fourier map but were refined with distance restraints of O—H = 0.84±0.01 Å and N—H = 0.88±0.01 Å, and with Uiso(H) set to 1.5Ueq(O) and 1.2Ueq(N).Multi-component crystals, incorporating co-crystals, salts and
salts, attract continuing interest for a wide variety of applications as this technology may be employed, for example, to provide additives to promote the growth of crystals, to stabilize unusual and unstable coformers, to generate new luminescent materials, to separate enantiomers, to facilitate determination where the molecule of concern does not have a significant anomalous scatterer, etc (Aakeröy, 2015; Tiekink, 2012). Arguably, the area attracting most interest in this context is the applications of multi-component crystals in the pharmaceutical industry (Duggirala et al., 2016). Controlled/designed crystallization of multi-component crystals requires reliable synthon formation between the various components and that, of course, is the challenge of crystal engineering, let alone engineering small aggregates within crystals (Tiekink, 2014).Systematic work on synthon propensities in multi-component crystals have revealed that carboxylic acids have a great likelihood of forming hydroxy-O—H···N hydrogen bonds when co-crystallized with molecules with pyridyl residues (Shattock et al., 2008). A plausible explanation for this reliability is the formation of a supporting carbonyl-O···H interaction involving the hydrogen atom adjacent to the pyridyl-nitrogen atom. Indeed, in the absence of competing hydrogen-bonding functionality, the resulting seven-membered {···HOCO···HCN} heterosynthon is formed in more than 98% of relevant crystal structures (Shattock et al., 2008). Recent systematic work in this phenomenon relates to molecules shown in Scheme 1, where isomeric molecules with two pyridyl rings separated by a diamide residue have been co-crystallized with various carboxylic acids (Arman, Miller et al., 2012; Arman et al., 2013, Syed et al., 2016; Jotani et al., 2016). As a continuation of these studies, the title 2:1
was isolated and characterized crystallographically and by Hirshfeld surface analysis.The title
Fig. 1, was formed from the 1:1 co-crystallization of 2-methylbenzoic acid and N,N'-bis(pyridin-4-ylmethyl)ethanediamide (hereafter, the diamide) conducted in ethanol solution. The comprises a full acid molecule in a general position and half a diamide molecule, located about a centre of inversion, so the is formulated as a 2:1 acid:diamide co-crystal.In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached with the O3—C8—C9—C10 torsion angle being 150.23 (14)°, and, to a first approximation, with the carbonyl-O3 atom and methyl group lying to the same side of the molecule as indicated in the hydroxy-O2—C8—C9—C10(H) torsion angle of -27.92 (17)°. The structure of the parent acid and several co-crystals featuring coformers shown in Scheme 2 are available for comparison; data are collected in Table 1. The common feature of all structures is the relative orientation of the carbonyl-O and methyl groups. Twists in the acid molecules vary from almost co-planar to the situation found in the title
with an even split of conformations amongst the six known structures.In the centrosymmetric diamide, the central C4N2O2 core is essentially planar with an r.m.s. deviation (O1, N2, C6, C7 and symmetry equivalents) = 0.031 Å. This arrangement facilitates the formation of an intramolecular amide-N—H···O(amide) hydrogen bond, Table 2. The pyridyl rings occupy positions on opposite sides of the central residue and project almost prime to this with the central residue/pyridyl dihedral angle being 88.60 (5)°. The aforementioned structural features match literature precedents, i.e. the two polymorphic forms of the parent diamide and the diamide in co-crystals with carboxylic acids and in a salt with a carboxylate, Table 3. Finally, the central C—C bond length, considered long for a Csp2—Csp2 bond (Spek, 2009), matches the structural data included in Table 3; see Scheme 3 for chemical diagrams of coformers.
The molecular packing of the title 2) via amide-N—H···O(carbonyl) hydrogen bonds as well as methylene-C—H···O(amide) interactions, Fig. 2b. Within layers, π–π interactions occur between pyridyl rings, and between layers additional π–π interactions occur between pyridyl/benzene and benzene/benzene rings to consolidate the three-dimensional packing, Table 4 and Fig. 2c. Globally, the packing may be described as comprising alternating layers of aromatic rings and non-aromatic residues.
is dominated by hydrogen bonding, detailed in Table 2. The carboxylic acid is connected to the diamide via hydroxy-O—H···N(pyridyl) hydrogen bonds to form a three-molecule aggregate, Fig. 2a. The interacting residues are not co-planar with the dihedral angle between the pyridyl and three CO2 groups being 25.67 (8)° so that the carbonyl-O3···H3 distance is 2.60 Å. This suggests only a minor role for the putative seven-membered heterosynthon {···OCOH···NCH} mentioned in the Chemical context and is consistent with the significant hydrogen-bonding interaction involving the carbonyl-O3 atom to another residue. Indeed, the three-molecule aggregates are connected into a supramolecular layer parallel to (12Crystal Explorer 3.1 (Wolff et al., 2012) was used to generate Hirshfeld surfaces mapped over dnorm, de, electrostatic potential, shape-index and curvedness for the title 2:1
The electrostatic potentials were calculated using TONTO (Spackman et al., 2008; Jayatilaka et al., 2005) integrated with Crystal Explorer, using the experimentally determined geometry as the input. Further, the electrostatic potentials were mapped on Hirshfeld surfaces using the STO-3G basis set at Hartree–Fock theory over a range ±0.15 au. The contact distances di and de from the Hirshfeld surface to the nearest atom inside and outside, respectively, enabled the analysis of the intermolecular interactions through the mapping of dnorm. The combination of di and de in the form of a two-dimensional fingerprint plot (Rohl et al., 2008) provides a summary of the intermolecular contacts.The strong hydroxy-O—H···N(pyridyl) and amide-N—H···O(carbonyl) interactions between the acid and diamide molecules are visualized as bright-red spots at the respective donor and acceptor atoms on the Hirshfeld surfaces mapped over dnorm, and labelled as 1 and 2 in Fig. 3. The intermolecular methylene-C—H···O(amide) interactions appears as faint-red spots in Fig. 3b, marked with a `3'. The immediate environment about each molecule highlighting close contacts to the Hirshfeld surface by neighbouring molecules is shown in Fig. 4. The full fingerprint (FP) plots showing various crystal packing interactions in the acid, diamide and 2:1
are shown in Fig. 5; the contributions from various contacts are listed in Table 5.The prominent long spike at de + di ~1.8 Å in the upper left (donor) region for the FP plot of the acid corresponds to H···N contacts and the spike at the same distance in the lower right (acceptor) region of the FP plot for the diamide are the result of hydroxy-O—H···N(pyridyl) interactions, Figs 5a and b, respectively. However, these spikes are not apparent in the overall FP for the 2:1 as they no longer contribute to the surface of the resultant aggregate, Fig. 5c. Pairs of somewhat blunted spikes corresponding to N···H/H···N contacts at de + di ~2.9 Å result from amide-N—H···O(carbonyl) interactions between the acid and diamide molecules are evident in the overall FP, Fig. 5c.
The O···H/H···O contacts, which make a significant contribution to the molecular packing, show different characteristic features in the respective delineated FP plots of the acid and diamide. For the acid, Fig. 5a, a long prominent spike at de + di ~2.5 Å in the acceptor region corresponds to a 6.6% contribution from H···O contacts to the Hirshfeld surface, and a short spike at de + di ~2.15 Å in the donor region with a 14.0% contribution from O···H contacts. The reverse situation is observed for the diamide molecule wherein the FP plot, Fig. 5b, contains a long prominent spike in the donor region and the short spike in the acceptor at the same de + di distance, and with 10.7 and 14.9% contributions from O···H and H···O contacts, respectively.
FP plots for the ~1.2 Å for each of the constituents, with percentage contributions of 48.7 and 45.2% for the acid and diamide molecules, respectively. The overall 49.9% contribution to Hirshfeld surface of the results in nearly symmetric through the superimposition of individual fingerprint plots, Fig. 6a.
delineated into H···H, O···H/H···O, C···H/H···C, N···H/H···N and C···C are shown in Figs 6a–e, respectively. The H···H contacts appear as asymmetrically scattered points covering a large region of the FP plot with a single broad peak at de = diThe FP plot for O···H/H···O contacts, Fig. 6b, has two pairs of spikes superimposed in the (de, di) region with minimum de + di distances ~2.15 and 2.5 Å. These correspond to a 21.3% contribution to the Hirshfeld surface, and reflect the presence of intermolecular N—H···O and C—H···O interactions, identified with labels 1 and 2 in Fig. 6b. The 15.9 % contribution from the C···H/H···C contacts to the Hirshfeld surface results in a symmetric pair of wings, Fig. 6c. The FP plot corresponding to C···C contacts, Fig. 6e, in the (de, di ) region between 1.7 to 2.2 Å appears as the two distinct, overlapping triangles identified with red and yellow boundaries in Fig. 6e, and shows two types of π–π stacking interactions: one between dissimilar rings (pyridyl and benzene) and the other between symmetry-related rings (benzene and benzene, and pyridyl and pyridyl). The presence of these π–π stacking interactions is also indicated by the appearance of red and blue triangles on the shape-indexed surfaces identified with arrows in the images of Fig. 7, and in the flat regions on the Hirshfeld surfaces mapped with curvedness in Fig. 8.
The intermolecular interactions were further assessed by using the enrichment ratio, ER (Jelsch et al., 2014). This is a relatively new descriptor and is based on Hirshfeld surface analysis. The ER for the π–π interactions is reflected in the relatively high ER values, Table 6. The absence of C—H···π and related interactions is reflected in low ER values, i. e. < 0.8. The N···H/H···N contacts in a crystal having ER values equal to greater than or equal to unity for the acid/diamide molecules reduces to 0.84 in the 2:1 co-crystals, indicating a reduced likelihood of formation once the is stabilized by other interactions. The enrichment ratios for other contacts are of low significance as they are derived from less important interactions which have small contributions to Hirshfeld surfaces.
together with those for the acid and diamide molecules are listed in Table 6. The largest contribution to the Hirshfeld surfaces are from H···H contacts, Table 5, and their respective ER values are close to unity. This shows that the contribution from dispersive forces are significant in the molecule packing of the title 2:1 in contrast to that observed in a related, recently published structure, namely, the salt [2-({[(pyridin-1-ium-2-ylmethyl)carbamoyl]formamido}methyl)-pyridin-1-ium][3,5-dicarboxybenzoate], i.e. containing the diprotonated form of the isomeric 2-pyridyl-containing diamide (Syed et al., 2016). In the latter, O···H/H···O contacts make the greatest contribution to the crystal packing. It is the presence of different substituents in the benzene ring in the acid molecule in the i.e. methyl, as opposed to carboxylic acid/carboxylate groups in the salt, that provides an explanation for this difference. The ER value for O···H/H···O contacts, i.e. 1.30, shows the propensity to form hydroxy-O—H···N(pyridyl) and amide-N—H···O(carbonyl) hydrogen bonds as well as methylene-C—H···O(amide) interactions. The formation of extensiveAs mentioned in the Chemical context, the diamide in the title 2:1
and isomeric forms have attracted considerable interest in the crystal engineering community no doubt owing to the variable functional groups and conformational flexibility. Indeed, the diamide in the title featured in early studies of halogen I···N halogen bonding (Goroff et al., 2005). Over and above these investigations, the role of the diamide in coordination chemistry has also been studied. Bidentate bridging is the prominent coordination mode observed in both neutral, e.g. [HgI2(diamide)]n (Zeng et al., 2008) and charged, e.g. polymeric [Ag(diamide)NO3]n (Schauer et al., 1998) and oligiomeric {[Ph2PCH2PPh2Au2(diamide)]2(ClO4)4(EtOEt)4} (Tzeng et al., 2006), species.For related literature, see: Aakeröy (2015); Arman, Kaulgud et al. (2012); Arman et al. (2013); Arman et al. (2009); Arman, Miller et al. (2012); Day et al. (2009); Duggirala et al. (2016); Ebenezer et al. (2011); Goroff et al. (2005); Groom & Allen (2014); Jelsch et al. (2014); Jotani et al. (2016); Lee (2010); Lee & Wang (2007); Nguyen et al. (2001); Nguyen et al. (1998); Rohl et al. (2008); Schauer et al. (1997); Schauer et al. (1998); Shattock et al. (2008); Spackman et al. (2008) Syed et al. (2016); Thakur & Desiraju (2008); Tiekink (2012); Tiekink (2014); Tzeng et al. (2006); Wales et al. (2012); Zeng et al. (2008).
The diamide (0.2 g), prepared in accord with the literature procedure (Schauer et al., 1997), in ethanol (10 ml) was added to a ethanol solution (10 ml) of 2-methylbenzoic acid (Merck, 0.1 g). The mixture was stirred for 1 h at room temperature after which a white precipitate was deposited. The solution was filtered by vacuum suction, and the filtrate was then left to stand under ambient conditions, yielding colourless prisms after 2 weeks.
detailsCrystal data, data collection and structure
details are summarized in Table 7. The carbon-bound H-atoms were placed in calculated positions (C—H = 0.95–0.99 Å) and were included in the in the riding-model approximation, with Uiso(H) set to 1.2Ueq(C). The oxygen- and nitrogen-bound H-atoms were located in a difference Fourier map but were refined with distance restraints of O—H = 0.84±0.01 Å and N—H = 0.88±0.01 Å, and with Uiso(H) set to 1.5Ueq(O) and 1.2Ueq(N).Data collection: CrysAlis PRO (Agilent, 2014); cell
CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. The molecular structures of the molecules comprising the title co-crystal showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level: (a) 2-methylbenzoic acid and (b) N,N'-bis(pyridin-4-ylmethyl)ethanediamide; unlabelled atoms in the diamide are generated by the symmetry operation (-1 - x, 2 - y, 1 - z). | |
Fig. 2. Molecular packing in the title co-crystal: (a) three-molecule aggregate sustained by hydroxy-O—H···N(pyridyl) hydrogen bonds, (b) supramolecular layers whereby the aggregates in (a) are connected by amide-N—H···O(carbonyl) and methylene-C—H···O(amide) interactions, and (c) a view of the unit-cell contents shown in projection down the a axis, highlighting the intra- and inter-layer π–π interactions to consolidate a three-dimensional architecture. The O—H···N, N—H···O,C—H···O and π–π interactions are shown as orange, blue, green and purple dashed lines, respectively. | |
Fig. 3. Views of the Hirshfeld surfaces mapped over dnorm: (a) acid and (b) diamide in the title 2:1 co-crystal. The contact points (red) are labelled to indicate the atoms participating in the intermolecular interactions. | |
Fig. 4. Hirshfeld surfaces mapped over electrostatic potential showing hydrogen bonds with neighbouring molecules with the reference molecule being the (a) acid and (b) diamide. | |
Fig. 5. The two-dimensional fingerprint plots for the (a) acid, (b) diamide and (c) overall 2:1 co-crystal. | |
Fig. 6. The two-dimensional fingerprint plot for the title 2:1 co-crystal showing contributions from different contacts: (a) H···H, (b) O···H/H···O, (c) C···H/H···C, (d) N···H/H···N and (e) C···C. | |
Fig. 7. Hirshfeld surfaces mapped over the shape index for (a) the acid and (b) the diamide, highlighting the regions involved in π–π stacking interactions. | |
Fig. 8. Hirshfeld surfaces mapped over curvedness for (a) the acid and (b) the diamide, highlighting the regions involved in π–π stacking interactions. |
C14H14N4O2·2C8H8O2 | Z = 1 |
Mr = 542.58 | F(000) = 286 |
Triclinic, P1 | Dx = 1.376 Mg m−3 |
a = 6.8948 (5) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.7219 (5) Å | Cell parameters from 3840 reflections |
c = 9.9621 (7) Å | θ = 3.5–30.0° |
α = 82.971 (5)° | µ = 0.10 mm−1 |
β = 81.638 (6)° | T = 100 K |
γ = 85.686 (5)° | Prism, colourless |
V = 654.58 (8) Å3 | 0.21 × 0.15 × 0.10 mm |
Agilent Technologies SuperNova Dual diffractometer with an Atlas detector | 2993 independent reflections |
Radiation source: SuperNova (Mo) X-ray Source | 2358 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.044 |
Detector resolution: 10.4041 pixels mm-1 | θmax = 27.5°, θmin = 3.0° |
ω scan | h = −8→8 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014) | k = −12→12 |
Tmin = 0.580, Tmax = 1.000 | l = −12→12 |
15067 measured reflections |
Refinement on F2 | 2 restraints |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.041 | w = 1/[σ2(Fo2) + (0.0434P)2 + 0.2225P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.106 | (Δ/σ)max < 0.001 |
S = 1.06 | Δρmax = 0.34 e Å−3 |
2993 reflections | Δρmin = −0.23 e Å−3 |
188 parameters |
C14H14N4O2·2C8H8O2 | γ = 85.686 (5)° |
Mr = 542.58 | V = 654.58 (8) Å3 |
Triclinic, P1 | Z = 1 |
a = 6.8948 (5) Å | Mo Kα radiation |
b = 9.7219 (5) Å | µ = 0.10 mm−1 |
c = 9.9621 (7) Å | T = 100 K |
α = 82.971 (5)° | 0.21 × 0.15 × 0.10 mm |
β = 81.638 (6)° |
Agilent Technologies SuperNova Dual diffractometer with an Atlas detector | 2993 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014) | 2358 reflections with I > 2σ(I) |
Tmin = 0.580, Tmax = 1.000 | Rint = 0.044 |
15067 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 188 parameters |
wR(F2) = 0.106 | 2 restraints |
S = 1.06 | Δρmax = 0.34 e Å−3 |
2993 reflections | Δρmin = −0.23 e Å−3 |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
O1 | −0.26845 (15) | 1.04906 (10) | 0.41903 (10) | 0.0202 (2) | |
N1 | 0.10595 (19) | 0.54943 (12) | 0.25502 (12) | 0.0194 (3) | |
N2 | −0.34990 (18) | 0.85635 (11) | 0.56442 (12) | 0.0157 (3) | |
H2N | −0.4483 (18) | 0.8165 (15) | 0.6161 (14) | 0.019* | |
C1 | −0.0650 (2) | 0.71369 (13) | 0.45691 (14) | 0.0159 (3) | |
C2 | 0.1324 (2) | 0.66915 (14) | 0.44690 (15) | 0.0183 (3) | |
H2 | 0.2123 | 0.6945 | 0.5089 | 0.022* | |
C3 | 0.2113 (2) | 0.58766 (14) | 0.34574 (15) | 0.0197 (3) | |
H3 | 0.3461 | 0.5574 | 0.3403 | 0.024* | |
C4 | −0.0837 (2) | 0.59250 (14) | 0.26467 (15) | 0.0205 (3) | |
H4 | −0.1600 | 0.5661 | 0.2009 | 0.025* | |
C5 | −0.1746 (2) | 0.67411 (14) | 0.36357 (15) | 0.0182 (3) | |
H5 | −0.3100 | 0.7024 | 0.3672 | 0.022* | |
C6 | −0.1494 (2) | 0.80107 (14) | 0.57005 (14) | 0.0165 (3) | |
H3A | −0.1442 | 0.7438 | 0.6589 | 0.020* | |
H3B | −0.0648 | 0.8796 | 0.5668 | 0.020* | |
C7 | −0.3901 (2) | 0.97768 (13) | 0.49211 (14) | 0.0154 (3) | |
O2 | 0.30435 (15) | 0.41238 (10) | 0.06130 (11) | 0.0200 (2) | |
H2O | 0.242 (2) | 0.4581 (16) | 0.1233 (15) | 0.030* | |
O3 | 0.50558 (15) | 0.34690 (10) | 0.21737 (10) | 0.0210 (2) | |
C8 | 0.4571 (2) | 0.33987 (13) | 0.10547 (14) | 0.0160 (3) | |
C9 | 0.5600 (2) | 0.24530 (13) | 0.00615 (14) | 0.0157 (3) | |
C10 | 0.4507 (2) | 0.19550 (14) | −0.08313 (15) | 0.0183 (3) | |
H10 | 0.3160 | 0.2250 | −0.0817 | 0.022* | |
C11 | 0.5355 (2) | 0.10374 (14) | −0.17385 (15) | 0.0222 (3) | |
H11 | 0.4586 | 0.0672 | −0.2314 | 0.027* | |
C12 | 0.7337 (2) | 0.06622 (14) | −0.17932 (15) | 0.0220 (3) | |
H12 | 0.7947 | 0.0059 | −0.2432 | 0.026* | |
C13 | 0.8436 (2) | 0.11621 (14) | −0.09211 (15) | 0.0195 (3) | |
H13 | 0.9800 | 0.0904 | −0.0983 | 0.023* | |
C14 | 0.7595 (2) | 0.20349 (13) | 0.00468 (14) | 0.0166 (3) | |
C15 | 0.8858 (2) | 0.24942 (15) | 0.09983 (16) | 0.0225 (3) | |
H15A | 0.8762 | 0.3510 | 0.0945 | 0.034* | |
H15B | 1.0226 | 0.2173 | 0.0735 | 0.034* | |
H15C | 0.8409 | 0.2100 | 0.1935 | 0.034* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0158 (5) | 0.0209 (5) | 0.0229 (6) | −0.0017 (4) | −0.0010 (4) | −0.0004 (4) |
N1 | 0.0224 (7) | 0.0166 (6) | 0.0179 (6) | 0.0030 (5) | 0.0001 (5) | −0.0027 (5) |
N2 | 0.0132 (6) | 0.0170 (6) | 0.0166 (6) | 0.0005 (4) | −0.0005 (5) | −0.0031 (4) |
C1 | 0.0179 (7) | 0.0129 (6) | 0.0155 (7) | −0.0004 (5) | 0.0001 (6) | 0.0004 (5) |
C2 | 0.0170 (7) | 0.0173 (6) | 0.0208 (7) | −0.0004 (5) | −0.0025 (6) | −0.0029 (5) |
C3 | 0.0170 (7) | 0.0164 (6) | 0.0243 (8) | 0.0011 (5) | 0.0006 (6) | −0.0018 (6) |
C4 | 0.0238 (8) | 0.0190 (7) | 0.0190 (7) | 0.0025 (6) | −0.0048 (6) | −0.0037 (6) |
C5 | 0.0160 (7) | 0.0185 (7) | 0.0199 (7) | 0.0031 (5) | −0.0028 (6) | −0.0039 (5) |
C6 | 0.0150 (7) | 0.0176 (6) | 0.0170 (7) | 0.0011 (5) | −0.0021 (6) | −0.0035 (5) |
C7 | 0.0176 (8) | 0.0158 (6) | 0.0137 (7) | −0.0006 (5) | −0.0019 (6) | −0.0058 (5) |
O2 | 0.0177 (6) | 0.0225 (5) | 0.0196 (5) | 0.0044 (4) | −0.0008 (4) | −0.0067 (4) |
O3 | 0.0239 (6) | 0.0232 (5) | 0.0156 (5) | 0.0019 (4) | −0.0012 (4) | −0.0042 (4) |
C8 | 0.0154 (7) | 0.0151 (6) | 0.0163 (7) | −0.0020 (5) | 0.0015 (6) | −0.0005 (5) |
C9 | 0.0174 (7) | 0.0144 (6) | 0.0140 (7) | −0.0017 (5) | 0.0009 (6) | 0.0001 (5) |
C10 | 0.0166 (7) | 0.0197 (7) | 0.0180 (7) | 0.0005 (5) | −0.0023 (6) | −0.0008 (5) |
C11 | 0.0283 (9) | 0.0211 (7) | 0.0185 (8) | −0.0015 (6) | −0.0062 (6) | −0.0039 (6) |
C12 | 0.0296 (9) | 0.0182 (7) | 0.0172 (7) | 0.0046 (6) | −0.0005 (6) | −0.0045 (6) |
C13 | 0.0198 (8) | 0.0186 (7) | 0.0183 (7) | 0.0028 (6) | 0.0004 (6) | −0.0008 (5) |
C14 | 0.0185 (7) | 0.0140 (6) | 0.0163 (7) | −0.0021 (5) | 0.0000 (6) | 0.0001 (5) |
C15 | 0.0173 (8) | 0.0259 (7) | 0.0251 (8) | −0.0003 (6) | −0.0024 (6) | −0.0075 (6) |
O1—C7 | 1.2252 (17) | O2—C8 | 1.3217 (17) |
N1—C4 | 1.3364 (19) | O2—H2O | 0.853 (9) |
N1—C3 | 1.3401 (19) | O3—C8 | 1.2205 (17) |
N2—C7 | 1.3371 (17) | C8—C9 | 1.4994 (18) |
N2—C6 | 1.4510 (18) | C9—C10 | 1.396 (2) |
N2—H2N | 0.874 (9) | C9—C14 | 1.403 (2) |
C1—C5 | 1.385 (2) | C10—C11 | 1.385 (2) |
C1—C2 | 1.390 (2) | C10—H10 | 0.9500 |
C1—C6 | 1.5166 (18) | C11—C12 | 1.383 (2) |
C2—C3 | 1.3820 (19) | C11—H11 | 0.9500 |
C2—H2 | 0.9500 | C12—C13 | 1.384 (2) |
C3—H3 | 0.9500 | C12—H12 | 0.9500 |
C4—C5 | 1.3892 (19) | C13—C14 | 1.3964 (19) |
C4—H4 | 0.9500 | C13—H13 | 0.9500 |
C5—H5 | 0.9500 | C14—C15 | 1.503 (2) |
C6—H3A | 0.9900 | C15—H15A | 0.9800 |
C6—H3B | 0.9900 | C15—H15B | 0.9800 |
C7—C7i | 1.536 (3) | C15—H15C | 0.9800 |
C4—N1—C3 | 117.67 (12) | C8—O2—H2O | 110.8 (13) |
C7—N2—C6 | 121.54 (12) | O3—C8—O2 | 123.13 (12) |
C7—N2—H2N | 117.2 (11) | O3—C8—C9 | 123.68 (13) |
C6—N2—H2N | 120.9 (11) | O2—C8—C9 | 113.16 (12) |
C5—C1—C2 | 117.97 (13) | C10—C9—C14 | 120.20 (12) |
C5—C1—C6 | 123.56 (13) | C10—C9—C8 | 118.28 (13) |
C2—C1—C6 | 118.47 (13) | C14—C9—C8 | 121.48 (12) |
C3—C2—C1 | 119.31 (14) | C11—C10—C9 | 121.07 (14) |
C3—C2—H2 | 120.3 | C11—C10—H10 | 119.5 |
C1—C2—H2 | 120.3 | C9—C10—H10 | 119.5 |
N1—C3—C2 | 122.93 (14) | C12—C11—C10 | 118.97 (14) |
N1—C3—H3 | 118.5 | C12—C11—H11 | 120.5 |
C2—C3—H3 | 118.5 | C10—C11—H11 | 120.5 |
N1—C4—C5 | 123.05 (14) | C11—C12—C13 | 120.28 (13) |
N1—C4—H4 | 118.5 | C11—C12—H12 | 119.9 |
C5—C4—H4 | 118.5 | C13—C12—H12 | 119.9 |
C1—C5—C4 | 119.07 (13) | C12—C13—C14 | 121.79 (14) |
C1—C5—H5 | 120.5 | C12—C13—H13 | 119.1 |
C4—C5—H5 | 120.5 | C14—C13—H13 | 119.1 |
N2—C6—C1 | 115.06 (12) | C13—C14—C9 | 117.56 (13) |
N2—C6—H3A | 108.5 | C13—C14—C15 | 119.00 (13) |
C1—C6—H3A | 108.5 | C9—C14—C15 | 123.43 (12) |
N2—C6—H3B | 108.5 | C14—C15—H15A | 109.5 |
C1—C6—H3B | 108.5 | C14—C15—H15B | 109.5 |
H3A—C6—H3B | 107.5 | H15A—C15—H15B | 109.5 |
O1—C7—N2 | 125.26 (13) | C14—C15—H15C | 109.5 |
O1—C7—C7i | 121.45 (15) | H15A—C15—H15C | 109.5 |
N2—C7—C7i | 113.29 (15) | H15B—C15—H15C | 109.5 |
C5—C1—C2—C3 | −0.2 (2) | O2—C8—C9—C10 | −27.92 (17) |
C6—C1—C2—C3 | 179.02 (12) | O3—C8—C9—C14 | −27.8 (2) |
C4—N1—C3—C2 | −0.3 (2) | O2—C8—C9—C14 | 154.08 (12) |
C1—C2—C3—N1 | 0.4 (2) | C14—C9—C10—C11 | 0.4 (2) |
C3—N1—C4—C5 | 0.0 (2) | C8—C9—C10—C11 | −177.60 (12) |
C2—C1—C5—C4 | −0.1 (2) | C9—C10—C11—C12 | −2.8 (2) |
C6—C1—C5—C4 | −179.24 (12) | C10—C11—C12—C13 | 2.1 (2) |
N1—C4—C5—C1 | 0.2 (2) | C11—C12—C13—C14 | 0.9 (2) |
C7—N2—C6—C1 | −87.65 (15) | C12—C13—C14—C9 | −3.3 (2) |
C5—C1—C6—N2 | −7.47 (19) | C12—C13—C14—C15 | 177.62 (13) |
C2—C1—C6—N2 | 173.38 (12) | C10—C9—C14—C13 | 2.56 (19) |
C6—N2—C7—O1 | 4.4 (2) | C8—C9—C14—C13 | −179.48 (12) |
C6—N2—C7—C7i | −175.86 (13) | C10—C9—C14—C15 | −178.36 (13) |
O3—C8—C9—C10 | 150.23 (14) | C8—C9—C14—C15 | −0.4 (2) |
Symmetry code: (i) −x−1, −y+2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O1i | 0.87 (1) | 2.31 (1) | 2.7100 (16) | 108 (1) |
O2—H2O···N1 | 0.85 (2) | 1.79 (2) | 2.6378 (16) | 178 (2) |
N2—H2N···O3ii | 0.87 (1) | 2.17 (1) | 2.8933 (15) | 140 (1) |
C6—H3B···O1iii | 0.99 | 2.48 | 3.3461 (18) | 146 |
Symmetry codes: (i) −x−1, −y+2, −z+1; (ii) −x, −y+1, −z+1; (iii) −x, −y+2, −z+1. |
Compound | CH—C—C—OH | C6/CO2 | CSD Refcodeb | Ref. |
Parent compound | 1.7 (2) | 1.5 (5) | OTOLIC02 | Thakur & Desiraju (2008) |
1:1 Co-crystal with CF_1 | 7.5 (2) | 8.04 (9) | WICZUF | Day et al. (2009) |
1:1 Co-crystal with CF_2 | 4.25 (19) | 4.02 (12) | EXIBOD | Ebenezer et al. (2011) |
1:1 Co-crystal with CF_3 | 27.4 (3) | 27.8 (2) | EXIZIR | Ebenezer et al. (2011) |
1:1 Co-crystal with CF_4 | 23.0 (2) | 23.86 (8) | CEKLEL | Wales et al. (2012) |
Title co-crystal | -27.92 (18) | 28.51 (8) | – | This work |
Notes: (a) Refer to Scheme 2 for the chemical structures of coformers, CF_1–CF_4. (b) Groom & Allen (2014). |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O1i | 0.874 (13) | 2.313 (13) | 2.7100 (16) | 107.7 (11) |
O2—H2O···N1 | 0.852 (15) | 1.787 (15) | 2.6378 (16) | 178.1 (16) |
N2—H2N···O3ii | 0.874 (13) | 2.166 (14) | 2.8933 (15) | 140.4 (12) |
C6—H3B···O1iii | 0.99 | 2.48 | 3.3461 (18) | 146 |
Symmetry codes: (i) −x−1, −y+2, −z+1; (ii) −x, −y+1, −z+1; (iii) −x, −y+2, −z+1. |
Coformer | C4N2O2/N-ring | C(═O)—C(═O) | Refcodeb | Ref. |
–c,d | 74.90 (4) | 1.532 (2) | CICYOD01 | Lee (2010) |
–e | 68.83 (4); 70.89 (5) | 1.541 (3) | CICYOD | Lee & Wang (2007) |
80.46 (5); 83.35 (6) | 1.541 (3) | |||
CF_5c,f | 87.37 (4) | 1.534 (2) | NAXMEG | Arman, Kaulgud et al. (2012) |
CF_6c,f | 79.86 (4) | 1.542 (2) | AJEZEV | Arman et al. (2009) |
CF_7g | 70.50 (4); 76.89 (4) | 1.52 (2) | CAJRAH | Nguyen et al. (2001) |
CF_8c,g,h | 73.38 (11) | 1.523 (7) | SEPSIP | Nguyen et al. (1998) |
CF_8c,g,i | 72.87 (9) | 1.514 (5) | SEPSIP01 | Nguyen et al. (2001) |
CF_9c,f | 75.83 (5) | 1.543 (3) | TIPGUW | Arman et al. (2013) |
2-Methylbenzoic acid | 88.66 (4) | 1.5356 (19) | – | This work |
Notes: (a) Refer to Scheme 3 for the chemical structures of coformers, CF_5–CF_9; (b) Groom & Allen (2014); (c) molecule/dianion is centrosymmetric; (d) form I; (e) form II (two independent molecules); (f) 2:1 carboxylic acid/carboxylate diamide co-crystal/salt; (g) 1:1 dicarboxylic acid diamide co-crystal; (h) form I; (i) form II. |
Ring 1 | Ring 2 | Inter-centroid distance | Dihedral angle | Symmetry |
N1,C1–C5 | N1,C1–C5 | 3.5980 (8) | 0 | -x, 1 - y, 1 - z |
N1,C1–C5 | C9–C14 | 3.7833 (9) | 4.63 (7) | 1 - x, 1 - y, -z |
C9–C14 | C9–C14 | 3.8473 (8) | 0 | -1 - x, -y, -z |
Contact | Acid | Diamide | Co-crystal |
H···H | 48.7 | 45.2 | 49.9 |
O···H/H···O | 20.6 | 25.6 | 21.3 |
C···H/H···C | 16.7 | 12.0 | 15.9 |
N···H/H···N | 3.8 | 8.9 | 2.7 |
C···C | 5.9 | 6.4 | 6.6 |
Interaction | Acid | Diamide | Co-crystal |
H···H | 1.02 | 0.97 | 1.02 |
O···H/H···O | 1.22 | 1.46 | 1.30 |
C···C | 2.30 | 3.60 | 2.55 |
C···H/H···C | 0.75 | 0.66 | 0.71 |
N···H/H···N | 1.06 | 1.20 | 0.84 |
Experimental details
Crystal data | |
Chemical formula | C14H14N4O2·2C8H8O2 |
Mr | 542.58 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 100 |
a, b, c (Å) | 6.8948 (5), 9.7219 (5), 9.9621 (7) |
α, β, γ (°) | 82.971 (5), 81.638 (6), 85.686 (5) |
V (Å3) | 654.58 (8) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.21 × 0.15 × 0.10 |
Data collection | |
Diffractometer | Agilent Technologies SuperNova Dual diffractometer with an Atlas detector |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2014) |
Tmin, Tmax | 0.580, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15067, 2993, 2358 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.106, 1.06 |
No. of reflections | 2993 |
No. of parameters | 188 |
No. of restraints | 2 |
Δρmax, Δρmin (e Å−3) | 0.34, −0.23 |
Computer programs: CrysAlis PRO (Agilent, 2014), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
Footnotes
‡Additional correspondence author, e-mail: mmjotani@rediffmail.com.
Acknowledgements
The authors thank the Exploratory Research Grant Scheme (ER008-2013A) for support.
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