2-[4-Phenyl-5-(2-pyrid­yl)-4H-1,2,4-triazol-3-yl]nicotinic acid: a case of solvent-dependent polymorphism

The title compound, C₁₉H₁₃N₅O₂, crystallizes in two monoclinic forms depending on the solvent used. From methanol or acetone, a yellow form [(Ia), m.p. 533 K] in the space group P2₁ is obtained, while with ethanol as the solvent, an orange form [(Ib), m.p. 541 K] in the space group Cc results. The conformers observed in the two polymorphs differ primarily in the relative orientation of pyridine/phenyl and triazole rings. Mol­ecules of both polymorphs form chains through carboxyl O-H...N hydrogen bonding; however, in each crystal structure, a different group acts as acceptor, viz. a triazole and a pyridyl N atom for (Ia) and (Ib), respectively. This is the first case of polymorphism observed for crystals of a 3,4,5-tri­substituted 1,2,4-triazole derivative.

S1. Comment

The phenomenon of polymorphism plays a vital role in the manufacture of pharmaceuticals, as well as in other biological and chemical fields. Polymorphic solids of the same chemical compound differ in internal solid-state structure and, as a consequence, possess different chemical and physical properties, including thermodynamic, spectroscopic, kinetic or mechanic ones. These properties can have a direct impact on a substance's stability, solubility, bioavailability or activity. However, polymorphism is not very well understood either at the crystallographic or at the molecular level. Its occurrence is unpredictable and may be caused by small differences in crystallization temperature, pressure, acidity or the nature of the mother liquor from which the substance was crystallized (solvent-dependent polymorphism) (Bernstein, 2002).

The present study is a continuation of our investigations on the structural characterization of aromatic derivatives of 4H-1,2,4-triazole (Mazur et al., 2004a,b, 2007). The conformational flexibility of these molecules, arising from a potential rotation between aryl and triazole rings, gives the possibility of formation of polymorphic forms. However, thus far, no polymorphs have been found for 3,4,5-trisubstituted 1,2,4-triazole derivatives, both aromatic and aliphatic.

In this work, we report the crystal structures of two polymorphic forms of 5-(3-carboxyl-2-pyridyl)-4-(phenyl)-3-(2-pyridyl)-4H-1,2,4-triazole (Ia and Ib). The molecular structures observed in (Ia) and (Ib) (Fig. 1) are composed of a central 1,2,4-triazole ring, substituted at C5 by the 3-carboxyl-2-pyridyl group, at C3 by the 2-pyridyl group and at N4 by a phenyl group. The interatomic distances within the triazole rings are not equal, ranging from 1.300 (2) to 1.389 (2) Å (Tables 1 and 3). The C3—N4 and N4—C5 bond lengths indicate single-bond character, whereas the N1—C5 and N2—C3 distances are indicative of significant double-bond character. The substituent atoms C22 and C31 in both polymorphs as well as atom C12 in (Ib) are almost coplanar with the central triazole ring, whereas the C12 atom in (Ia) is displaced from the triazole plane by 0.151 (2) Å. This out-of-plane deformation may result from intermolecular interactions. The N21—C22 bonds in the pyridyl groups and N1—N2 bonds in the triazole rings are also influenced by intermolecular contacts. All four rings in both polymorphic forms are almost perfectly planar. As in all similar compounds reported in the Cambridge Structural Database (CSD, Version 5.29; Allen, 2002; refcodes: AYEFOZ, FAXRAY, FAXSON, HIYFAW, IWOROB, MATKOH, MEGWIF, MEGXAY, NIFJUH, NUBCES, QAYVOB, QUIWVOH, TAWMAG, VERYEX), these aromatic rings are not coplanar (Fig. 2). The interplanar angles between the triazole and its substituent rings are in the range 40.7 (2)-83.0 (2)° (Table 5). Moreover, the relative orientation of the N atoms of the 2-pyridyl substituents at C3 and C5 is opposite for the forms (Ia) and (Ib). Molecule (Ia) possesses transoidally oriented pyridyl groups, while (Ib) is a cisoid conformer (Fig. 2). Besides the orientation of the rings, another significant difference between polymorphic conformers is observed, which is the relative orientation of the N11—C16 pyridyl ring and the COOH group (substituted in its C13 position). The O1—C1—C13—C12 torsion angles indicate that the protonated carboxyl O1 atom is oriented trans in (Ia) and cis in (Ib) with respect to the pyridine C12 atom (Fig. 2). All these conformational differences are accompanied by different intermolecular O—H···N hydrogen-bonding patterns.

Substantial differences in the molecular packing of the polymorphs are observed (Figs. 3 and 4). The molecules of the yellow phase (Ia) are linked by strong O1—H1O···N2ⁱ [symmetry code (i): 2 - x, y + 1/2, 1 - z] hydrogen bonds (Table 2) forming a C(8) chain (Bernstein et al., 1995) parallel to the y axis (Fig. 5). These chains are enforced by weaker multicentre C—H···O/N intermolecular interactions, giving a complex three-dimensional framework.

In the structure of the orange polymorph (Ib) the carboxylic O1—H1O bond participates in formation of a strong hydrogen bond with the pyridyl N21 atom of the second molecule transformed by the c-glide plane (Table 4, Fig. 5). The resulting infinite chain (running along the z axis) is described as a C(10) motif. Moreover, short directional contacts between the carbonyl atom O2 and the triazole N1/C5 (x, 1 - y, z - 1/2) atoms are observed (Fig. 6), which might be attractive in nature (Desiraju & Steiner, 1999). In addition to these interactions, there are also numerous weak C—H···N-type hydrogen bonds between adjacent molecular columns. Atom C26 acts as a hydrogen-bond donor to the pyridyl atom N11 (Fig. 4) in the molecule at (x - 1/2, y + 1/2, z). Simultaneously, the phenyl C34—H34 atoms participate in formation of three-centre hydrogen bonds with triazole N1—N2 atoms of the next molecule, repeated by translation along the [010] direction. Propagation of these hydrogen bonds then links all molecules into the (001) sheets.

The two crystalline forms (Ia) and (Ib) are obtained from different solvents. It seems that the polarity of solvents and their ability to form solute–solvent aggregates of different structure results in variation of intermolecular contacts during the formation of the solid. In the case of (Ib), ethanol (or water) molecules promote formation of C—H···N hydrogen bonds and electrostatic C=O···triazole interactions which are of a more hydrophobic nature. Thus, the crystals of polymorph (Ib) have higher melting point (by 8 K) and density (by 0.056 g cm^-3).

Related literature

For related literature, see: Allen (2002); Bernstein (2002); Desiraju & Steiner (1999);

S2. Experimental

Plate-shaped yellow single crystals of polymorph (Ia) were obtained by recrystallization of the title compound from methanol and acetone solutions at room temperature. Prismatic orange crystals of the second polymorph (Ib) were obtained by recrystallization from 95% ethanol. The melting points determined on a Boëtius microscope were 533 K and 541 K for forms (Ia) and (Ib), respectively.

S3. Refinement

In the absence of significant anomalous scatter, it was impossible to establish unambiguously the absolute structures of both polymorphs crystallizing in the non-centrosymmetric space groups. Nevertheless, the enantiomer selected in each case gave a value of the Flack parameter closest to zero. H atoms bonded to the O1 atoms were located in the difference Fourier map and their positions were refined with fixed isotropic displacement parameters. All remaining H atoms were positioned geometrically and constrained, with C—H bond distances of 0.93 Å. The displacement parameters of the H atoms were set to U_iso(H) = 1.2 U_eq(C).

Computing details

For both compounds, data collection: KM-4 Software (Kuma, 1998); cell refinement: KM-4 Software (Kuma, 1998); data reduction: KM-4 Software (Kuma, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and enCIFer (Allen et al., 2004).

Figures

	Fig. 1. Molecules of the title compound with the atom-numbering schemes: (a) polymorphic form (Ia) and (b) form (Ib). Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Molecular fit of the triazole atoms of the (Ia) (filled lines) and (Ib) (outline) conformers, showing differing orientations of the substituent rings and carboxylic acid groups.
	Fig. 3. The molecular packing of (Ia), viewed along the y axis. Dashed lines indicate hydrogen bonds; H atoms have been omitted (except those forming O—H···N bonds).
	Fig. 4. The packing arrangement of molecules of (Ib), viewed along the z axis. Dashed lines indicate C—H···N hydrogen bonds (other H atoms have been omitted). Symmetry codes: (a): x, y + 1, z; (b): x - 1/2, y + 1/2, z.
	Fig. 5. The chains formed by the O—H···N intermolecular hydrogen bonds in the form (Ia) (up) and (Ib) (down). H atoms have been omitted.
	Fig. 6. Intermolecular O—H···N hydrogen bond and accompanying carbonyl··· triazole contact in (Ib). Symmetry code: (a): x, 1 - y, z - 1/2.

(Ia) 2-[4-Phenyl-5-(2-pyridyl)-4H-1,2,4-triazol-3-yl]nicotinic acid

Crystal data

C19H13N5O2	F(000) = 356
Mr = 343.34	Dx = 1.310 Mg m^−3
Monoclinic, P21	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2yb	Cell parameters from 48 reflections
a = 9.032 (3) Å	θ = 6–18°
b = 11.758 (2) Å	µ = 0.73 mm^−1
c = 9.208 (2) Å	T = 295 K
β = 117.11 (2)°	Plate, yellow
V = 870.4 (4) Å^3	0.58 × 0.42 × 0.36 mm
Z = 2

Data collection

Kuma KM-4 four-circle diffractometer	Rint = 0.026
Radiation source: fine-focus sealed tube	θmax = 80.5°, θmin = 5.4°
Graphite monochromator	h = −10→10
ω–2θ scans	k = −15→15
3798 measured reflections	l = 0→10
3577 independent reflections	3 standard reflections every 100 reflections
2628 reflections with I > 2σ(I)	intensity decay: 0.8%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.037	w = 1/[σ^2(Fo^2) + (0.0677P)^2 + 0.0089P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.104	(Δ/σ)max < 0.001
S = 1.06	Δρmax = 0.17 e Å^−3
3577 reflections	Δρmin = −0.15 e Å^−3
239 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.017 (2)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.3 (2)

Special details

Experimental. crystallizations from methanol and acetone

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.88170 (18)	0.15682 (13)	0.52367 (19)	0.0490 (4)
N2	0.79779 (18)	0.11734 (13)	0.36563 (19)	0.0488 (4)
C3	0.6404 (2)	0.14363 (14)	0.3086 (2)	0.0446 (4)
N4	0.61739 (16)	0.20125 (12)	0.42533 (17)	0.0412 (3)
C5	0.7716 (2)	0.20617 (14)	0.5565 (2)	0.0432 (3)
N21	0.4002 (3)	0.19321 (19)	0.0643 (2)	0.0755 (6)
C22	0.5116 (2)	0.11417 (17)	0.1443 (2)	0.0492 (4)
C23	0.5157 (3)	0.00945 (19)	0.0794 (3)	0.0644 (5)
H23	0.5950	−0.0445	0.1406	0.077*
C24	0.3986 (4)	−0.0134 (2)	−0.0792 (3)	0.0770 (7)
H24	0.4007	−0.0823	−0.1279	0.092*
C25	0.2816 (4)	0.0649 (3)	−0.1624 (3)	0.0850 (8)
H25	0.1994	0.0504	−0.2678	0.102*
C26	0.2872 (4)	0.1665 (3)	−0.0875 (3)	0.0942 (9)
H26	0.2070	0.2207	−0.1460	0.113*
C31	0.4674 (2)	0.24733 (14)	0.4213 (2)	0.0431 (4)
C32	0.3664 (3)	0.1784 (2)	0.4565 (3)	0.0662 (6)
H32	0.3897	0.1012	0.4756	0.079*
C33	0.2293 (3)	0.2245 (2)	0.4633 (3)	0.0744 (7)
H33	0.1591	0.1784	0.4866	0.089*
C34	0.1964 (3)	0.3393 (2)	0.4357 (3)	0.0687 (6)
H34	0.1050	0.3708	0.4418	0.082*
C35	0.2984 (3)	0.4067 (2)	0.3993 (4)	0.0768 (7)
H35	0.2754	0.4839	0.3796	0.092*
C36	0.4360 (3)	0.36047 (17)	0.3917 (3)	0.0633 (5)
H36	0.5056	0.4060	0.3669	0.076*
N11	0.7491 (2)	0.17968 (15)	0.7987 (2)	0.0638 (5)
C12	0.8031 (2)	0.24977 (15)	0.7187 (2)	0.0448 (4)
C1	0.9386 (2)	0.42650 (16)	0.6842 (2)	0.0476 (4)
O1	1.0688 (2)	0.48772 (16)	0.7760 (2)	0.0752 (5)
H1O	1.113 (4)	0.536 (3)	0.712 (4)	0.100*
O2	0.86796 (18)	0.42958 (12)	0.53827 (17)	0.0598 (4)
C13	0.8892 (2)	0.34925 (15)	0.7841 (2)	0.0464 (4)
C14	0.9276 (3)	0.3752 (2)	0.9435 (3)	0.0635 (5)
H14	0.9894	0.4397	0.9934	0.076*
C15	0.8725 (3)	0.3035 (3)	1.0279 (3)	0.0754 (7)
H15	0.8951	0.3196	1.1349	0.090*
C16	0.7846 (3)	0.2090 (2)	0.9514 (3)	0.0734 (6)
H16	0.7469	0.1619	1.0088	0.088*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0414 (7)	0.0529 (8)	0.0525 (9)	0.0023 (6)	0.0211 (6)	−0.0006 (6)
N2	0.0440 (8)	0.0540 (8)	0.0528 (9)	0.0042 (6)	0.0259 (7)	−0.0039 (7)
C3	0.0440 (9)	0.0451 (9)	0.0475 (10)	0.0032 (6)	0.0234 (7)	−0.0006 (6)
N4	0.0386 (6)	0.0414 (6)	0.0474 (7)	0.0013 (5)	0.0228 (5)	−0.0004 (6)
C5	0.0421 (8)	0.0412 (7)	0.0494 (9)	−0.0035 (6)	0.0236 (7)	0.0008 (7)
N21	0.0761 (12)	0.0753 (12)	0.0579 (10)	0.0235 (10)	0.0154 (9)	−0.0031 (9)
C22	0.0462 (9)	0.0563 (10)	0.0483 (10)	0.0022 (7)	0.0245 (7)	−0.0037 (7)
C23	0.0654 (12)	0.0584 (11)	0.0684 (13)	−0.0030 (10)	0.0297 (11)	−0.0108 (10)
C24	0.0870 (17)	0.0785 (16)	0.0647 (14)	−0.0181 (14)	0.0338 (13)	−0.0232 (12)
C25	0.0862 (18)	0.102 (2)	0.0542 (14)	−0.0094 (16)	0.0208 (13)	−0.0152 (13)
C26	0.0861 (18)	0.107 (2)	0.0611 (15)	0.0232 (16)	0.0088 (13)	−0.0024 (14)
C31	0.0394 (8)	0.0461 (8)	0.0471 (9)	0.0049 (7)	0.0224 (7)	−0.0005 (7)
C32	0.0518 (10)	0.0642 (13)	0.0905 (16)	0.0064 (9)	0.0393 (11)	0.0200 (11)
C33	0.0487 (11)	0.0965 (19)	0.0904 (17)	0.0039 (11)	0.0424 (11)	0.0181 (14)
C34	0.0487 (10)	0.0904 (17)	0.0701 (14)	0.0102 (11)	0.0297 (10)	−0.0152 (12)
C35	0.0747 (15)	0.0539 (12)	0.106 (2)	0.0150 (10)	0.0446 (15)	−0.0130 (11)
C36	0.0660 (12)	0.0442 (9)	0.0923 (16)	0.0004 (9)	0.0471 (12)	−0.0060 (10)
N11	0.0754 (11)	0.0586 (10)	0.0674 (11)	−0.0107 (8)	0.0414 (9)	0.0061 (8)
C12	0.0422 (8)	0.0474 (8)	0.0467 (9)	−0.0016 (7)	0.0220 (7)	0.0040 (7)
C1	0.0454 (9)	0.0499 (9)	0.0476 (9)	−0.0097 (7)	0.0213 (7)	−0.0049 (7)
O1	0.0767 (10)	0.0877 (12)	0.0580 (9)	−0.0434 (9)	0.0280 (7)	−0.0064 (7)
O2	0.0651 (8)	0.0602 (8)	0.0492 (7)	−0.0133 (7)	0.0218 (6)	0.0036 (6)
C13	0.0447 (8)	0.0513 (9)	0.0447 (9)	−0.0056 (7)	0.0217 (7)	−0.0016 (7)
C14	0.0676 (12)	0.0768 (14)	0.0482 (11)	−0.0159 (11)	0.0282 (10)	−0.0107 (10)
C15	0.0802 (15)	0.1031 (19)	0.0486 (12)	−0.0114 (14)	0.0343 (11)	−0.0046 (12)
C16	0.0873 (16)	0.0868 (16)	0.0588 (13)	−0.0092 (14)	0.0443 (12)	0.0131 (12)

Geometric parameters (Å, º)

N1—C5	1.300 (2)	C32—H32	0.9300
N1—N2	1.379 (2)	C33—C34	1.381 (4)
N2—C3	1.309 (2)	C33—H33	0.9300
C3—N4	1.364 (2)	C34—C35	1.367 (4)
C3—C22	1.469 (3)	C34—H34	0.9300
N4—C5	1.367 (2)	C35—C36	1.387 (3)
N4—C31	1.444 (2)	C35—H35	0.9300
C5—C12	1.479 (2)	C36—H36	0.9300
N21—C22	1.320 (3)	N11—C16	1.337 (3)
N21—C26	1.339 (3)	N11—C12	1.337 (2)
C22—C23	1.376 (3)	C12—C13	1.381 (2)
C23—C24	1.384 (3)	C1—O2	1.197 (2)
C23—H23	0.9300	C1—O1	1.307 (2)
C24—C25	1.347 (4)	C1—C13	1.498 (2)
C24—H24	0.9300	O1—H1O	1.02 (3)
C25—C26	1.369 (4)	C13—C14	1.380 (3)
C25—H25	0.9300	C14—C15	1.384 (4)
C26—H26	0.9300	C14—H14	0.9300
C31—C36	1.362 (3)	C15—C16	1.360 (4)
C31—C32	1.365 (3)	C15—H15	0.9300
C32—C33	1.379 (3)	C16—H16	0.9300
C5—N1—N2	106.5 (2)	C32—C33—C34	119.9 (2)
C3—N2—N1	108.5 (2)	C32—C33—H33	120.1
N2—C3—N4	109.2 (2)	C34—C33—H33	120.1
N2—C3—C22	124.3 (2)	C35—C34—C33	120.0 (2)
N4—C3—C22	126.5 (2)	C35—C34—H34	120.0
C3—N4—C5	104.9 (1)	C33—C34—H34	120.0
C3—N4—C31	130.1 (1)	C34—C35—C36	120.2 (2)
C5—N4—C31	125.0 (1)	C34—C35—H35	119.9
N1—C5—N4	110.8 (2)	C36—C35—H35	119.9
N1—C5—C12	125.0 (2)	C31—C36—C35	118.9 (2)
N4—C5—C12	123.8 (2)	C31—C36—H36	120.6
C22—N21—C26	116.2 (2)	C35—C36—H36	120.6
N21—C22—C23	123.5 (2)	C16—N11—C12	116.6 (2)
N21—C22—C3	116.9 (2)	N11—C12—C13	123.8 (2)
C23—C22—C3	119.5 (2)	N11—C12—C5	113.1 (2)
C22—C23—C24	118.2 (2)	C13—C12—C5	123.0 (2)
C22—C23—H23	120.9	O2—C1—O1	124.8 (2)
C24—C23—H23	120.9	O2—C1—C13	123.5 (2)
C25—C24—C23	119.5 (2)	O1—C1—C13	111.6 (2)
C25—C24—H24	120.3	C1—O1—H1O	114 (2)
C23—C24—H24	120.3	C14—C13—C12	118.0 (2)
C24—C25—C26	118.1 (2)	C14—C13—C1	121.2 (2)
C24—C25—H25	121.0	C12—C13—C1	120.8 (2)
C26—C25—H25	121.0	C13—C14—C15	118.8 (2)
N21—C26—C25	124.5 (3)	C13—C14—H14	120.6
N21—C26—H26	117.8	C15—C14—H14	120.6
C25—C26—H26	117.8	C16—C15—C14	118.8 (2)
C36—C31—C32	121.8 (2)	C16—C15—H15	120.6
C36—C31—N4	118.6 (2)	C14—C15—H15	120.6
C32—C31—N4	119.5 (2)	N11—C16—C15	124.0 (2)
C31—C32—C33	119.2 (2)	N11—C16—H16	118.0
C31—C32—H32	120.4	C15—C16—H16	118.0
C33—C32—H32	120.4
C5—N1—N2—C3	−0.2 (2)	C5—N4—C31—C32	−94.5 (2)
N1—N2—C3—N4	0.6 (2)	C36—C31—C32—C33	−0.4 (4)
N1—N2—C3—C22	−179.2 (2)	N4—C31—C32—C33	175.6 (2)
N2—C3—N4—C5	−0.8 (2)	C31—C32—C33—C34	−0.4 (4)
C22—C3—N4—C5	179.1 (2)	C32—C33—C34—C35	0.9 (4)
N2—C3—N4—C31	−179.7 (2)	C33—C34—C35—C36	−0.7 (4)
C22—C3—N4—C31	0.2 (3)	C32—C31—C36—C35	0.7 (4)
N2—N1—C5—N4	−0.2 (2)	N4—C31—C36—C35	−175.4 (2)
N2—N1—C5—C12	173.0 (2)	C34—C35—C36—C31	−0.1 (4)
C3—N4—C5—N1	0.6 (2)	C16—N11—C12—C13	−1.1 (3)
C31—N4—C5—N1	179.6 (2)	C16—N11—C12—C5	175.0 (2)
C3—N4—C5—C12	−172.7 (2)	N1—C5—C12—N11	−100.5 (2)
C31—N4—C5—C12	6.3 (3)	N4—C5—C12—N11	71.8 (2)
C26—N21—C22—C23	0.2 (4)	N1—C5—C12—C13	75.5 (2)
C26—N21—C22—C3	177.7 (2)	N4—C5—C12—C13	−112.1 (2)
N2—C3—C22—N21	−138.0 (2)	N11—C12—C13—C14	2.8 (3)
N4—C3—C22—N21	42.2 (3)	C5—C12—C13—C14	−172.8 (2)
N2—C3—C22—C23	39.7 (3)	N11—C12—C13—C1	−177.0 (2)
N4—C3—C22—C23	−140.2 (2)	C5—C12—C13—C1	7.4 (3)
N21—C22—C23—C24	1.2 (4)	O2—C1—C13—C14	−155.4 (2)
C3—C22—C23—C24	−176.3 (2)	O1—C1—C13—C14	25.6 (3)
C22—C23—C24—C25	−2.4 (4)	O2—C1—C13—C12	24.4 (3)
C23—C24—C25—C26	2.2 (5)	O1—C1—C13—C12	−154.5 (2)
C22—N21—C26—C25	−0.4 (5)	C12—C13—C14—C15	−2.7 (3)
C24—C25—C26—N21	−0.9 (5)	C1—C13—C14—C15	177.1 (2)
C3—N4—C31—C36	−99.6 (2)	C13—C14—C15—C16	1.0 (4)
C5—N4—C31—C36	81.7 (2)	C12—N11—C16—C15	−0.8 (4)
C3—N4—C31—C32	84.3 (2)	C14—C15—C16—N11	0.8 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···N2^i	1.02 (3)	1.61 (3)	2.628 (2)	172 (3)
C25—H25···O2^ii	0.93	2.69	3.474 (3)	143
C34—H34···O2^iii	0.93	2.75	3.657 (3)	164
C33—H33···N1^iii	0.93	2.69	3.520 (3)	149

Symmetry codes: (i) −x+2, y+1/2, −z+1; (ii) −x+1, y−1/2, −z; (iii) x−1, y, z.

(Ib) 2-[4-Phenyl-5-(2-pyridyl)-4H-1,2,4-triazol-3-yl]nicotinic acid

Crystal data

C19H13N5O2	F(000) = 712
Mr = 343.34	Dx = 1.366 Mg m^−3
Monoclinic, Cc	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: C -2yc	Cell parameters from 43 reflections
a = 16.384 (5) Å	θ = 6–16°
b = 9.725 (4) Å	µ = 0.76 mm^−1
c = 13.181 (3) Å	T = 295 K
β = 127.36 (4)°	Prism, orange
V = 1669.3 (13) Å^3	0.46 × 0.30 × 0.26 mm
Z = 4

Data collection

Kuma KM-4 four-circle diffractometer	Rint = 0.028
Radiation source: fine-focus sealed tube	θmax = 80.3°, θmin = 5.7°
Graphite monochromator	h = −20→20
ω–2θ scans	k = −10→10
6411 measured reflections	l = −16→16
3504 independent reflections	3 standard reflections every 100 reflections
2716 reflections with I > 2σ(I)	intensity decay: 0.1%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.040	w = 1/[σ^2(Fo^2) + (0.0691P)^2 + 0.1803P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.109	(Δ/σ)max = 0.023
S = 1.05	Δρmax = 0.17 e Å^−3
3504 reflections	Δρmin = −0.20 e Å^−3
239 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.0022 (2)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: −0.1 (3)

Special details

Experimental. crystallization from ethanol

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.45011 (13)	0.22361 (17)	0.19990 (17)	0.0389 (4)
N2	0.35506 (12)	0.22661 (17)	0.17596 (17)	0.0389 (4)
C3	0.32907 (14)	0.3558 (2)	0.16528 (18)	0.0330 (4)
N4	0.40289 (13)	0.43896 (13)	0.17999 (16)	0.0330 (3)
C5	0.47647 (14)	0.35032 (19)	0.20142 (17)	0.0328 (4)
N21	0.24275 (13)	0.49603 (19)	0.22475 (17)	0.0431 (4)
C22	0.23368 (14)	0.4060 (2)	0.14107 (18)	0.0357 (4)
C23	0.13960 (16)	0.3601 (2)	0.0354 (2)	0.0449 (5)
H23	0.1357	0.2969	−0.0204	0.054*
C24	0.05133 (16)	0.4102 (3)	0.0141 (2)	0.0535 (6)
H24	−0.0129	0.3807	−0.0561	0.064*
C25	0.05943 (17)	0.5035 (3)	0.0972 (3)	0.0566 (6)
H25	0.0011	0.5396	0.0840	0.068*
C26	0.15587 (18)	0.5428 (3)	0.2009 (2)	0.0526 (6)
H26	0.1610	0.6055	0.2578	0.063*
C31	0.40177 (19)	0.58629 (19)	0.1731 (3)	0.0454 (5)
C32	0.3191 (3)	0.6507 (3)	0.0662 (4)	0.0697 (8)
H32	0.2660	0.5990	−0.0016	0.084*
C33	0.3157 (4)	0.7916 (4)	0.0605 (6)	0.1072 (17)
H33	0.2599	0.8358	−0.0112	0.129*
C34	0.3944 (6)	0.8672 (4)	0.1603 (7)	0.122 (2)
H34	0.3910	0.9628	0.1565	0.147*
C35	0.4789 (4)	0.8035 (4)	0.2666 (6)	0.1030 (15)
H35	0.5328	0.8558	0.3327	0.124*
C36	0.4829 (3)	0.6582 (3)	0.2743 (3)	0.0657 (7)
H36	0.5385	0.6131	0.3454	0.079*
N11	0.65796 (13)	0.3546 (2)	0.33845 (17)	0.0453 (4)
C12	0.57290 (14)	0.3922 (2)	0.22373 (18)	0.0349 (4)
C13	0.57640 (16)	0.4646 (2)	0.13511 (19)	0.0401 (4)
C1	0.48459 (17)	0.5049 (2)	0.0046 (2)	0.0441 (5)
O1	0.40458 (12)	0.42436 (17)	−0.04499 (15)	0.0494 (4)
H1O	0.345 (3)	0.460 (4)	−0.138 (4)	0.100*
O2	0.48704 (16)	0.6016 (2)	−0.04985 (18)	0.0708 (6)
C14	0.67224 (17)	0.5023 (3)	0.1702 (2)	0.0526 (6)
H14	0.6773	0.5539	0.1149	0.063*
C15	0.75905 (17)	0.4632 (3)	0.2864 (2)	0.0582 (6)
H15	0.8237	0.4865	0.3108	0.070*
C16	0.74845 (17)	0.3884 (3)	0.3667 (2)	0.0536 (6)
H16	0.8077	0.3601	0.4447	0.064*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0388 (8)	0.0344 (8)	0.0488 (9)	0.0015 (7)	0.0293 (7)	0.0004 (7)
N2	0.0362 (8)	0.0333 (9)	0.0519 (9)	−0.0022 (7)	0.0292 (8)	−0.0038 (7)
C3	0.0343 (9)	0.0295 (10)	0.0372 (9)	−0.0028 (7)	0.0226 (8)	−0.0032 (7)
N4	0.0364 (6)	0.0268 (7)	0.0394 (7)	0.0012 (7)	0.0249 (6)	0.0002 (7)
C5	0.0332 (10)	0.0318 (10)	0.0329 (8)	0.0022 (7)	0.0198 (8)	0.0012 (7)
N21	0.0411 (9)	0.0440 (10)	0.0451 (9)	0.0008 (7)	0.0268 (8)	−0.0089 (7)
C22	0.0353 (9)	0.0315 (10)	0.0413 (10)	−0.0004 (7)	0.0238 (8)	−0.0011 (7)
C23	0.0379 (11)	0.0447 (12)	0.0479 (11)	−0.0015 (8)	0.0239 (10)	−0.0091 (9)
C24	0.0348 (10)	0.0540 (15)	0.0614 (14)	−0.0017 (9)	0.0238 (10)	−0.0103 (11)
C25	0.0421 (13)	0.0586 (15)	0.0743 (16)	0.0066 (10)	0.0381 (13)	−0.0046 (12)
C26	0.0505 (12)	0.0530 (14)	0.0608 (14)	0.0047 (11)	0.0373 (11)	−0.0135 (11)
C31	0.0602 (11)	0.0282 (9)	0.0724 (13)	0.0016 (11)	0.0530 (11)	0.0018 (11)
C32	0.0791 (19)	0.0519 (17)	0.103 (2)	0.0251 (14)	0.0681 (18)	0.0342 (15)
C33	0.141 (4)	0.052 (2)	0.200 (5)	0.041 (2)	0.140 (4)	0.056 (3)
C34	0.203 (5)	0.0357 (17)	0.251 (7)	0.016 (3)	0.202 (6)	0.022 (3)
C35	0.165 (4)	0.0495 (19)	0.181 (4)	−0.049 (2)	0.151 (4)	−0.049 (2)
C36	0.0896 (19)	0.0433 (14)	0.099 (2)	−0.0222 (13)	0.0751 (18)	−0.0229 (13)
N11	0.0346 (9)	0.0519 (11)	0.0415 (10)	0.0015 (7)	0.0191 (8)	0.0060 (7)
C12	0.0359 (9)	0.0326 (10)	0.0391 (10)	0.0019 (7)	0.0243 (8)	0.0001 (8)
C13	0.0411 (10)	0.0413 (11)	0.0415 (10)	−0.0022 (8)	0.0269 (9)	−0.0006 (8)
C1	0.0497 (11)	0.0460 (12)	0.0408 (9)	−0.0044 (9)	0.0296 (9)	0.0010 (8)
O1	0.0405 (8)	0.0611 (10)	0.0402 (7)	−0.0061 (7)	0.0212 (6)	0.0087 (7)
O2	0.0755 (12)	0.0702 (12)	0.0458 (8)	−0.0195 (9)	0.0259 (8)	0.0145 (8)
C14	0.0477 (13)	0.0653 (16)	0.0517 (12)	−0.0112 (10)	0.0338 (11)	−0.0017 (11)
C15	0.0351 (11)	0.0791 (17)	0.0587 (14)	−0.0087 (11)	0.0276 (10)	−0.0032 (12)
C16	0.0363 (11)	0.0640 (15)	0.0487 (12)	−0.0010 (10)	0.0197 (10)	0.0048 (11)

Geometric parameters (Å, º)

N1—C5	1.302 (3)	C32—H32	0.9300
N1—N2	1.389 (2)	C33—C34	1.370 (8)
N2—C3	1.306 (3)	C33—H33	0.9300
C3—N4	1.368 (2)	C34—C35	1.382 (7)
C3—C22	1.476 (3)	C34—H34	0.9300
N4—C5	1.365 (2)	C35—C36	1.415 (5)
N4—C31	1.435 (2)	C35—H35	0.9300
C5—C12	1.478 (3)	C36—H36	0.9300
N21—C26	1.338 (3)	N11—C16	1.332 (3)
N21—C22	1.344 (3)	N11—C12	1.343 (3)
C22—C23	1.382 (3)	C12—C13	1.395 (3)
C23—C24	1.384 (3)	C13—C14	1.390 (3)
C23—H23	0.9300	C13—C1	1.495 (3)
C24—C25	1.365 (4)	C1—O2	1.198 (3)
C24—H24	0.9300	C1—O1	1.311 (3)
C25—C26	1.375 (4)	O1—H1O	1.06 (4)
C25—H25	0.9300	C14—C15	1.367 (3)
C26—H26	0.9300	C14—H14	0.9300
C31—C36	1.372 (4)	C15—C16	1.379 (4)
C31—C32	1.377 (4)	C15—H15	0.9300
C32—C33	1.372 (5)	C16—H16	0.9300
C5—N1—N2	107.4 (2)	C34—C33—C32	120.0 (5)
C3—N2—N1	107.0 (2)	C34—C33—H33	120.0
N2—C3—N4	110.6 (2)	C32—C33—H33	120.0
N2—C3—C22	125.1 (2)	C33—C34—C35	120.8 (3)
N4—C3—C22	124.4 (2)	C33—C34—H34	119.6
C5—N4—C3	104.5 (1)	C35—C34—H34	119.6
C5—N4—C31	128.3 (2)	C34—C35—C36	119.7 (4)
C3—N4—C31	127.3 (2)	C34—C35—H35	120.2
N1—C5—N4	110.6 (2)	C36—C35—H35	120.2
N1—C5—C12	124.6 (2)	C31—C36—C35	117.6 (4)
N4—C5—C12	124.8 (2)	C31—C36—H36	121.2
C26—N21—C22	117.2 (2)	C35—C36—H36	121.2
N21—C22—C23	122.5 (2)	C16—N11—C12	117.8 (2)
N21—C22—C3	117.6 (2)	N11—C12—C13	122.6 (2)
C23—C22—C3	119.9 (2)	N11—C12—C5	113.8 (2)
C22—C23—C24	118.7 (2)	C13—C12—C5	123.7 (2)
C22—C23—H23	120.7	C14—C13—C12	117.8 (2)
C24—C23—H23	120.7	C14—C13—C1	117.3 (2)
C25—C24—C23	119.4 (2)	C12—C13—C1	124.9 (2)
C25—C24—H24	120.3	O2—C1—O1	123.9 (2)
C23—C24—H24	120.3	O2—C1—C13	121.3 (2)
C24—C25—C26	118.4 (2)	O1—C1—C13	114.9 (2)
C24—C25—H25	120.8	C1—O1—H1O	109 (2)
C26—C25—H25	120.8	C15—C14—C13	119.8 (2)
N21—C26—C25	123.8 (2)	C15—C14—H14	120.1
N21—C26—H26	118.1	C13—C14—H14	120.1
C25—C26—H26	118.1	C14—C15—C16	118.4 (2)
C36—C31—C32	122.3 (2)	C14—C15—H15	120.8
C36—C31—N4	118.7 (2)	C16—C15—H15	120.8
C32—C31—N4	119.1 (2)	N11—C16—C15	123.6 (2)
C33—C32—C31	119.5 (4)	N11—C16—H16	118.2
C33—C32—H32	120.2	C15—C16—H16	118.2
C31—C32—H32	120.2
C5—N1—N2—C3	−0.5 (2)	C3—N4—C31—C32	−54.3 (3)
N1—N2—C3—N4	0.6 (2)	C36—C31—C32—C33	−1.4 (4)
N1—N2—C3—C22	−179.3 (2)	N4—C31—C32—C33	177.9 (3)
N2—C3—N4—C5	−0.4 (2)	C31—C32—C33—C34	0.4 (5)
C22—C3—N4—C5	179.4 (2)	C32—C33—C34—C35	1.2 (6)
N2—C3—N4—C31	179.1 (2)	C33—C34—C35—C36	−1.9 (6)
C22—C3—N4—C31	−1.0 (3)	C32—C31—C36—C35	0.7 (4)
N2—N1—C5—N4	0.3 (2)	N4—C31—C36—C35	−178.5 (2)
N2—N1—C5—C12	−179.9 (2)	C34—C35—C36—C31	0.9 (4)
C3—N4—C5—N1	0.0 (2)	C16—N11—C12—C13	−0.2 (3)
C31—N4—C5—N1	−179.5 (2)	C16—N11—C12—C5	−179.9 (2)
C3—N4—C5—C12	−179.7 (2)	N1—C5—C12—N11	−61.4 (3)
C31—N4—C5—C12	0.7 (3)	N4—C5—C12—N11	118.4 (2)
C26—N21—C22—C23	−1.1 (3)	N1—C5—C12—C13	119.0 (2)
C26—N21—C22—C3	178.9 (2)	N4—C5—C12—C13	−61.2 (3)
N2—C3—C22—N21	124.0 (2)	N11—C12—C13—C14	−2.1 (3)
N4—C3—C22—N21	−55.8 (3)	C5—C12—C13—C14	177.5 (2)
N2—C3—C22—C23	−56.0 (3)	N11—C12—C13—C1	177.8 (2)
N4—C3—C22—C23	124.2 (2)	C5—C12—C13—C1	−2.6 (3)
N21—C22—C23—C24	0.8 (4)	C14—C13—C1—O2	−25.3 (3)
C3—C22—C23—C24	−179.2 (2)	C12—C13—C1—O2	154.8 (2)
C22—C23—C24—C25	0.3 (4)	C14—C13—C1—O1	152.7 (2)
C23—C24—C25—C26	−1.0 (4)	C12—C13—C1—O1	−27.2 (3)
C22—N21—C26—C25	0.3 (4)	C12—C13—C14—C15	2.6 (4)
C24—C25—C26—N21	0.7 (4)	C1—C13—C14—C15	−177.3 (2)
C5—N4—C31—C36	−55.6 (3)	C13—C14—C15—C16	−0.9 (4)
C3—N4—C31—C36	125.0 (2)	C12—N11—C16—C15	2.1 (4)
C5—N4—C31—C32	125.1 (2)	C14—C15—C16—N11	−1.6 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···N21^i	1.06 (4)	1.61 (4)	2.660 (3)	172 (4)
C34—H34···N1^ii	0.93	2.65	3.541 (4)	160
C34—H34···N2^ii	0.93	2.68	3.582 (4)	164
C26—H26···N11^iii	0.93	2.66	3.522 (3)	155
C23—H23···N11^iv	0.93	2.57	3.484 (3)	169

Symmetry codes: (i) x, −y+1, z−1/2; (ii) x, y+1, z; (iii) x−1/2, y+1/2, z; (iv) x−1/2, −y+1/2, z−1/2.