Concomitant polymorphs of 2-imino-2H-chromene-3-carb­oxy­lic acid amide: experimental and quantum chemical study

2-Imino­coumarin-3-carboxamide (2-imino-2 H-chromene-3-carb­oxy­lic acid) is a perspective compound for use in the pharmaceutical industry. This compound crystallized from several solvents as two concomitant polymorphic forms. The monoclinic polymorph, crystallized initially, is formed due to strong N—H...O hydrogen bonds, weak C—H...O and C—H...N(π) hydrogen bonds, and stacking interactions of `head-to-head' type. The triclinic polymorphic form obtained due to slow evaporation of the same solution is formed due to only strong intermolecular interactions, N—H...O hydrogen bonds of two types, and stacking interactions of two types. Analysis of pairwise interaction energies showed that the monoclinic structure is columnar while the triclinic one is layered. Calculations in a periodic approximation of their lattice energies confirmed that the monoclinic polymorphic crystals are metastable as compared to the stable triclinic polymorph. Further quantum chemical modeling of possible structure deformations proved that both concomitant polymorphs can not be transformed into a new polymorphic form under external influence.

Computing details

(1m)

Crystal data

C10H8N2O2	F(000) = 392
Mr = 188.18	Dx = 1.444 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 4.7332 (3) Å	Cell parameters from 1318 reflections
b = 14.6353 (10) Å	θ = 4.5–28.8°
c = 12.5289 (8) Å	µ = 0.10 mm^−1
β = 94.037 (5)°	T = 296 K
V = 865.75 (10) Å^3	Needle, colourless
Z = 4	0.2 × 0.05 × 0.05 mm

Data collection

Xcalibur, Sapphire3 diffractometer	1186 reflections with I > 2σ(I)
Detector resolution: 16.1827 pixels mm^-1	Rint = 0.064
ω scans	θmax = 25.0°, θmin = 3.2°
Absorption correction: multi-scan CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −5→5
Tmin = 0.770, Tmax = 1.000	k = −17→17
5418 measured reflections	l = −14→14
1523 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.050	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.156	w = 1/[σ^2(Fo^2) + (0.084P)^2 + 0.0891P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
1523 reflections	Δρmax = 0.15 e Å^−3
138 parameters	Δρmin = −0.18 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
O1	0.7329 (3)	0.28954 (9)	0.23738 (10)	0.0471 (4)
O2	0.2571 (3)	0.40696 (10)	0.53312 (12)	0.0564 (5)
N2	0.1336 (4)	0.46744 (13)	0.37184 (18)	0.0522 (5)
H2A	0.019 (6)	0.5093 (18)	0.399 (2)	0.076 (8)*
H2B	0.167 (5)	0.4681 (16)	0.303 (2)	0.066 (7)*
N1	0.4119 (4)	0.40271 (13)	0.20494 (16)	0.0538 (5)
H1	0.469 (5)	0.3908 (16)	0.138 (2)	0.065*
C8	0.4909 (4)	0.34895 (12)	0.38711 (15)	0.0362 (5)
C6	0.8335 (4)	0.22509 (12)	0.41197 (15)	0.0385 (5)
C9	0.5376 (4)	0.34987 (12)	0.27331 (15)	0.0392 (5)
C1	0.8784 (4)	0.22807 (13)	0.30390 (15)	0.0390 (5)
C10	0.2839 (4)	0.41142 (12)	0.43620 (16)	0.0404 (5)
C7	0.6344 (4)	0.28893 (13)	0.45161 (15)	0.0392 (5)
H7	0.604111	0.288646	0.524144	0.047*
C5	0.9822 (4)	0.15972 (14)	0.47483 (17)	0.0468 (5)
H5	0.957114	0.155884	0.547645	0.056*
C2	1.0656 (4)	0.17065 (14)	0.25750 (18)	0.0489 (6)
H2	1.093822	0.174866	0.184954	0.059*
C4	1.1661 (4)	0.10095 (14)	0.4289 (2)	0.0524 (6)
H4	1.262168	0.056755	0.470630	0.063*
C3	1.2085 (5)	0.10741 (14)	0.3208 (2)	0.0541 (6)
H3	1.335902	0.068186	0.290897	0.065*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0541 (9)	0.0525 (9)	0.0354 (8)	0.0065 (6)	0.0073 (6)	−0.0010 (6)
O2	0.0663 (10)	0.0634 (10)	0.0413 (10)	0.0192 (7)	0.0156 (7)	0.0049 (7)
N2	0.0566 (11)	0.0549 (12)	0.0455 (12)	0.0155 (9)	0.0074 (9)	0.0059 (9)
N1	0.0642 (12)	0.0602 (12)	0.0371 (11)	0.0100 (9)	0.0045 (9)	0.0080 (9)
C8	0.0343 (9)	0.0366 (10)	0.0379 (11)	−0.0026 (7)	0.0049 (8)	−0.0006 (8)
C6	0.0364 (10)	0.0397 (11)	0.0397 (11)	−0.0018 (8)	0.0042 (8)	−0.0036 (8)
C9	0.0401 (10)	0.0397 (11)	0.0380 (11)	−0.0033 (8)	0.0035 (8)	−0.0020 (8)
C1	0.0377 (10)	0.0393 (10)	0.0397 (11)	−0.0021 (8)	0.0015 (8)	−0.0041 (8)
C10	0.0404 (10)	0.0419 (11)	0.0392 (12)	−0.0017 (8)	0.0056 (8)	0.0015 (8)
C7	0.0402 (10)	0.0458 (11)	0.0323 (10)	−0.0048 (8)	0.0068 (8)	−0.0029 (8)
C5	0.0456 (11)	0.0498 (12)	0.0448 (12)	0.0030 (9)	0.0028 (9)	0.0018 (9)
C2	0.0500 (12)	0.0502 (12)	0.0470 (12)	0.0018 (9)	0.0076 (9)	−0.0125 (10)
C4	0.0496 (12)	0.0445 (12)	0.0621 (15)	0.0088 (9)	−0.0032 (10)	−0.0017 (10)
C3	0.0510 (12)	0.0476 (13)	0.0642 (16)	0.0057 (10)	0.0072 (10)	−0.0172 (11)

Geometric parameters (Å, º)

O1—C9	1.377 (2)	C6—C7	1.440 (3)
O1—C1	1.377 (2)	C6—C5	1.398 (3)
O2—C10	1.232 (2)	C1—C2	1.379 (3)
N2—H2A	0.90 (3)	C7—H7	0.9300
N2—H2B	0.88 (3)	C5—H5	0.9300
N2—C10	1.322 (3)	C5—C4	1.378 (3)
N1—H1	0.92 (3)	C2—H2	0.9300
N1—C9	1.270 (2)	C2—C3	1.366 (3)
C8—C9	1.458 (3)	C4—H4	0.9300
C8—C10	1.503 (3)	C4—C3	1.387 (3)
C8—C7	1.345 (3)	C3—H3	0.9300
C6—C1	1.386 (3)
C9—O1—C1	122.66 (15)	O2—C10—C8	119.13 (17)
H2A—N2—H2B	121 (2)	N2—C10—C8	117.77 (19)
C10—N2—H2A	120.2 (18)	C8—C7—C6	122.12 (18)
C10—N2—H2B	118.2 (16)	C8—C7—H7	118.9
C9—N1—H1	110.5 (15)	C6—C7—H7	118.9
C9—C8—C10	122.86 (17)	C6—C5—H5	120.0
C7—C8—C9	119.25 (17)	C4—C5—C6	120.0 (2)
C7—C8—C10	117.88 (17)	C4—C5—H5	120.0
C1—C6—C7	117.75 (17)	C1—C2—H2	120.8
C1—C6—C5	117.79 (17)	C3—C2—C1	118.3 (2)
C5—C6—C7	124.46 (18)	C3—C2—H2	120.8
O1—C9—C8	117.72 (16)	C5—C4—H4	119.9
N1—C9—O1	117.60 (18)	C5—C4—C3	120.3 (2)
N1—C9—C8	124.67 (18)	C3—C4—H4	119.9
O1—C1—C6	120.47 (17)	C2—C3—C4	120.87 (19)
O1—C1—C2	116.85 (17)	C2—C3—H3	119.6
C2—C1—C6	122.68 (18)	C4—C3—H3	119.6
O2—C10—N2	123.09 (19)
O1—C1—C2—C3	−178.51 (17)	C10—C8—C9—N1	0.3 (3)
C6—C1—C2—C3	1.1 (3)	C10—C8—C7—C6	178.84 (16)
C6—C5—C4—C3	1.2 (3)	C7—C8—C9—O1	−1.2 (3)
C9—O1—C1—C6	−0.4 (3)	C7—C8—C9—N1	179.17 (18)
C9—O1—C1—C2	179.21 (15)	C7—C8—C10—O2	1.5 (3)
C9—C8—C10—O2	−179.65 (17)	C7—C8—C10—N2	−176.95 (17)
C9—C8—C10—N2	1.9 (3)	C7—C6—C1—O1	−0.9 (3)
C9—C8—C7—C6	−0.1 (3)	C7—C6—C1—C2	179.51 (17)
C1—O1—C9—N1	−178.89 (16)	C7—C6—C5—C4	179.27 (18)
C1—O1—C9—C8	1.5 (2)	C5—C6—C1—O1	178.46 (15)
C1—C6—C7—C8	1.1 (3)	C5—C6—C1—C2	−1.1 (3)
C1—C6—C5—C4	0.0 (3)	C5—C6—C7—C8	−178.18 (17)
C1—C2—C3—C4	0.1 (3)	C5—C4—C3—C2	−1.3 (3)
C10—C8—C9—O1	179.95 (15)

(1t)

Crystal data

C10H8N2O2	Z = 2
Mr = 188.18	F(000) = 196
Triclinic, P1	Dx = 1.406 Mg m^−3
a = 7.0199 (12) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.0720 (13) Å	Cell parameters from 444 reflections
c = 9.6216 (12) Å	θ = 3.6–24.3°
α = 91.482 (12)°	µ = 0.10 mm^−1
β = 98.773 (14)°	T = 296 K
γ = 109.115 (16)°	Plate, colourless
V = 444.57 (13) Å^3	0.16 × 0.15 × 0.04 mm

Data collection

Xcalibur, Sapphire3 diffractometer	649 reflections with I > 2σ(I)
Detector resolution: 16.1827 pixels mm^-1	Rint = 0.092
ω scans	θmax = 25.0°, θmin = 3.5°
Absorption correction: multi-scan CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −8→8
Tmin = 0.151, Tmax = 1.000	k = −8→8
3405 measured reflections	l = −11→10
1564 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.086	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.273	w = 1/[σ^2(Fo^2) + (0.1091P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.96	(Δ/σ)max < 0.001
1564 reflections	Δρmax = 0.30 e Å^−3
136 parameters	Δρmin = −0.26 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
O1	0.2695 (4)	0.2183 (5)	0.5689 (3)	0.0723 (10)
O2	0.9652 (4)	0.4311 (5)	0.8052 (3)	0.0842 (12)
N2	0.7262 (6)	0.4171 (6)	0.9393 (4)	0.0745 (12)
H2A	0.831 (7)	0.472 (7)	1.016 (5)	0.089*
H2B	0.573 (7)	0.388 (7)	0.930 (4)	0.089*
N1	0.3359 (5)	0.3005 (6)	0.8054 (4)	0.0734 (12)
H1	0.192 (7)	0.266 (7)	0.791 (4)	0.088*
C8	0.6208 (6)	0.3245 (6)	0.6886 (4)	0.0518 (10)
C10	0.7856 (6)	0.3963 (6)	0.8177 (4)	0.0633 (13)
C1	0.3319 (7)	0.1966 (6)	0.4438 (4)	0.0615 (12)
C6	0.5360 (6)	0.2367 (6)	0.4348 (4)	0.0585 (11)
C9	0.4055 (6)	0.2817 (6)	0.6942 (4)	0.0577 (11)
C7	0.6813 (7)	0.3053 (6)	0.5654 (5)	0.0615 (12)
H7	0.820163	0.336796	0.563212	0.074*
C2	0.1793 (7)	0.1268 (7)	0.3265 (5)	0.0763 (14)
H2	0.042330	0.096940	0.334244	0.092*
C5	0.5898 (8)	0.2138 (7)	0.3044 (5)	0.0759 (14)
H5	0.726717	0.245439	0.295782	0.091*
C3	0.2359 (9)	0.1031 (8)	0.1989 (5)	0.0880 (17)
H3	0.135690	0.058830	0.118801	0.106*
C4	0.4376 (10)	0.1432 (8)	0.1868 (5)	0.0900 (17)
H4	0.472246	0.123045	0.099434	0.108*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0508 (18)	0.093 (3)	0.071 (2)	0.0265 (16)	0.0005 (15)	−0.0115 (17)
O2	0.0497 (19)	0.112 (3)	0.087 (2)	0.0260 (16)	0.0060 (16)	−0.0179 (19)
N2	0.056 (2)	0.098 (3)	0.066 (3)	0.025 (2)	0.0076 (19)	−0.019 (2)
N1	0.043 (2)	0.099 (3)	0.078 (3)	0.023 (2)	0.0165 (18)	−0.015 (2)
C8	0.051 (2)	0.051 (3)	0.055 (2)	0.0190 (18)	0.0090 (18)	−0.0050 (19)
C10	0.054 (3)	0.065 (3)	0.074 (3)	0.026 (2)	0.009 (2)	−0.007 (2)
C1	0.064 (3)	0.059 (3)	0.061 (3)	0.024 (2)	0.002 (2)	−0.007 (2)
C6	0.065 (3)	0.050 (3)	0.060 (3)	0.017 (2)	0.013 (2)	0.004 (2)
C9	0.051 (2)	0.062 (3)	0.065 (3)	0.0249 (19)	0.013 (2)	−0.001 (2)
C7	0.056 (2)	0.059 (3)	0.071 (3)	0.0194 (19)	0.015 (2)	−0.003 (2)
C2	0.069 (3)	0.077 (4)	0.078 (3)	0.027 (2)	−0.001 (2)	−0.004 (3)
C5	0.081 (3)	0.072 (3)	0.073 (3)	0.022 (3)	0.021 (3)	0.001 (3)
C3	0.102 (5)	0.083 (4)	0.071 (4)	0.031 (3)	−0.009 (3)	0.004 (3)
C4	0.126 (5)	0.080 (4)	0.064 (3)	0.034 (3)	0.021 (3)	0.007 (3)

Geometric parameters (Å, º)

O1—C1	1.364 (5)	C1—C2	1.386 (6)
O1—C9	1.381 (5)	C6—C7	1.452 (6)
O2—C10	1.228 (5)	C6—C5	1.385 (6)
N2—H2A	0.93 (5)	C7—H7	0.9300
N2—H2B	1.02 (5)	C2—H2	0.9300
N2—C10	1.321 (5)	C2—C3	1.369 (6)
N1—H1	0.94 (5)	C5—H5	0.9300
N1—C9	1.263 (5)	C5—C4	1.387 (7)
C8—C10	1.511 (5)	C3—H3	0.9300
C8—C9	1.451 (5)	C3—C4	1.374 (7)
C8—C7	1.337 (5)	C4—H4	0.9300
C1—C6	1.383 (6)
C1—O1—C9	122.3 (3)	N1—C9—O1	118.5 (4)
H2A—N2—H2B	131 (4)	N1—C9—C8	124.3 (4)
C10—N2—H2A	116 (3)	C8—C7—C6	121.8 (4)
C10—N2—H2B	113 (2)	C8—C7—H7	119.1
C9—N1—H1	114 (3)	C6—C7—H7	119.1
C9—C8—C10	122.7 (4)	C1—C2—H2	120.9
C7—C8—C10	117.1 (4)	C3—C2—C1	118.2 (5)
C7—C8—C9	120.2 (4)	C3—C2—H2	120.9
O2—C10—N2	123.5 (4)	C6—C5—H5	120.3
O2—C10—C8	119.3 (4)	C6—C5—C4	119.4 (5)
N2—C10—C8	117.2 (4)	C4—C5—H5	120.3
O1—C1—C6	121.9 (4)	C2—C3—H3	119.3
O1—C1—C2	116.4 (4)	C2—C3—C4	121.4 (5)
C6—C1—C2	121.6 (4)	C4—C3—H3	119.3
C1—C6—C7	116.6 (4)	C5—C4—H4	119.9
C1—C6—C5	119.2 (4)	C3—C4—C5	120.2 (5)
C5—C6—C7	124.2 (4)	C3—C4—H4	119.9
O1—C9—C8	117.3 (3)
O1—C1—C6—C7	−0.6 (6)	C9—O1—C1—C2	178.3 (4)
O1—C1—C6—C5	−179.3 (4)	C9—C8—C10—O2	−179.5 (4)
O1—C1—C2—C3	180.0 (4)	C9—C8—C10—N2	0.9 (6)
C10—C8—C9—O1	179.6 (3)	C9—C8—C7—C6	−1.7 (6)
C10—C8—C9—N1	0.2 (7)	C7—C8—C10—O2	−1.0 (6)
C10—C8—C7—C6	179.7 (3)	C7—C8—C10—N2	179.4 (4)
C1—O1—C9—N1	179.1 (4)	C7—C8—C9—O1	1.1 (6)
C1—O1—C9—C8	−0.3 (6)	C7—C8—C9—N1	−178.3 (4)
C1—C6—C7—C8	1.5 (6)	C7—C6—C5—C4	178.7 (4)
C1—C6—C5—C4	−2.7 (7)	C2—C1—C6—C7	−178.8 (4)
C1—C2—C3—C4	1.2 (8)	C2—C1—C6—C5	2.5 (7)
C6—C1—C2—C3	−1.7 (7)	C2—C3—C4—C5	−1.5 (8)
C6—C5—C4—C3	2.2 (8)	C5—C6—C7—C8	−179.9 (4)
C9—O1—C1—C6	0.1 (7)