Crystallographic, spectroscopic and thermal studies of 1-(4-bromo­phen­yl)-5-(2,5-dimethyl-1H-pyrrol-1-yl)-3-methyl-1H-pyrazole

The new title pyrrole–pyrazole derivative, C₁₆H₁₆BrN₃, was synthesized through a citric acid-catalyzed Paal–Knorr reaction between acetonylacetone and 1-(4-bromo­phen­yl)-3-methyl-1H-pyrazol-5-amine under mild reaction conditions. This synthetic protocol is noteworthy for its utilization of stoichiometric amounts of the reactants, an ecofriendly solvent and a cost-effective, non-toxic and biodegradable organocatalyst. A comprehensive understanding of the mol­ecular structure was gained through spectroscopic, thermal and X-ray crystallographic analyses. The crystal structure is characterized by weak inter­actions, where only C—H...π connections contribute to the hydro­gen-bond contacts. The supra­molecular assembly is controlled by dispersion forces. However, the energy frameworks demonstrate that these forces act in three dimensions, providing enough stability, as observed in TGA–DSC (thermogravimetric analysis–differential scanning calorimetry) studies.

Computing details

Data collection: CrysAlis PRO (Rigaku OD, 2018); cell refinement: CrysAlis PRO (Rigaku OD, 2018); data reduction: CrysAlis PRO (Rigaku OD, 2018); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

1-(4-Bromophenyl)-5-(2,5-dimethyl-1H-pyrrol-1-yl)-3-methyl-1H-pyrazole

Crystal data

C16H16BrN3	Z = 2
Mr = 330.23	F(000) = 336
Triclinic, P1	Dx = 1.442 Mg m^−3
a = 7.8073 (9) Å	Cu Kα radiation, λ = 1.54184 Å
b = 9.8003 (11) Å	Cell parameters from 4699 reflections
c = 10.7900 (9) Å	θ = 4.3–75.6°
α = 72.964 (9)°	µ = 3.62 mm^−1
β = 85.084 (8)°	T = 298 K
γ = 74.448 (10)°	Parallelepiped, colorless
V = 760.43 (15) Å^3	0.18 × 0.15 × 0.13 mm

Data collection

Rigaku OD SuperNova Dual source diffractometer with an Atlas detector	3159 independent reflections
Radiation source: SuperNova (Cu) micro-focus sealed X-ray Source	2788 reflections with I > 2σ(I)
Detector resolution: 10.6144 pixels mm^-1	Rint = 0.036
ω scans	θmax = 76.8°, θmin = 4.3°
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2018)	h = −9→9
Tmin = 0.675, Tmax = 1.000	k = −12→12
9437 measured reflections	l = −13→12

Refinement

Refinement on F^2	Primary atom site location: iterative
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0576P)^2 + 0.1134P] where P = (Fo^2 + 2Fc^2)/3
3159 reflections	(Δ/σ)max < 0.001
184 parameters	Δρmax = 0.36 e Å^−3
0 restraints	Δρmin = −0.50 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
C1	0.2490 (3)	0.5663 (2)	0.1542 (2)	0.0450 (4)
C2	0.1722 (3)	0.4688 (3)	0.1220 (2)	0.0572 (5)
H2	0.166664	0.471556	0.035467	0.069*
C3	0.1041 (4)	0.3680 (3)	0.2168 (3)	0.0609 (6)
H3	0.052474	0.303324	0.194433	0.073*
C4	0.1131 (3)	0.3637 (2)	0.3451 (2)	0.0501 (4)
C5	0.1883 (3)	0.4587 (3)	0.3795 (2)	0.0542 (5)
H5	0.193069	0.455154	0.466231	0.065*
C6	0.2572 (3)	0.5602 (3)	0.2841 (2)	0.0544 (5)
H6	0.309064	0.624246	0.307192	0.065*
N7	0.3132 (2)	0.6699 (2)	0.05201 (16)	0.0471 (4)
C8	0.3810 (3)	0.7853 (2)	0.05202 (19)	0.0453 (4)
C9	0.4197 (3)	0.8512 (3)	−0.0734 (2)	0.0526 (5)
H9	0.467135	0.932623	−0.103685	0.063*
C10	0.3727 (3)	0.7701 (3)	−0.1471 (2)	0.0509 (5)
N11	0.3074 (3)	0.6622 (2)	−0.07258 (17)	0.0526 (4)
N12	0.4014 (2)	0.82314 (19)	0.16522 (16)	0.0448 (4)
C13	0.5529 (3)	0.7721 (3)	0.2396 (2)	0.0534 (5)
C14	0.5152 (4)	0.8267 (3)	0.3435 (2)	0.0592 (5)
H14	0.593279	0.809846	0.409946	0.071*
C15	0.3375 (3)	0.9135 (3)	0.3341 (2)	0.0560 (5)
H15	0.278618	0.964019	0.392502	0.067*
C16	0.2683 (3)	0.9097 (2)	0.2242 (2)	0.0490 (4)
C17	0.7186 (4)	0.6760 (4)	0.1996 (3)	0.0771 (8)
H17A	0.696301	0.584679	0.198422	0.116*
H17B	0.811456	0.656195	0.260171	0.116*
H17C	0.754414	0.725315	0.114647	0.116*
C18	0.0884 (4)	0.9773 (4)	0.1678 (3)	0.0700 (7)
H18A	0.096814	1.042931	0.083065	0.105*
H18B	0.015052	1.031619	0.222457	0.105*
H18C	0.036689	0.901175	0.161302	0.105*
C19	0.3871 (4)	0.7952 (3)	−0.2908 (2)	0.0642 (6)
H19A	0.353668	0.718165	−0.313239	0.096*
H19B	0.507448	0.794824	−0.318236	0.096*
H19C	0.309407	0.888883	−0.333010	0.096*
Br20	0.01414 (4)	0.22824 (3)	0.47636 (3)	0.06862 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0475 (10)	0.0455 (10)	0.0442 (10)	−0.0134 (8)	0.0025 (7)	−0.0154 (8)
C2	0.0696 (13)	0.0664 (14)	0.0473 (11)	−0.0298 (11)	0.0041 (10)	−0.0237 (10)
C3	0.0728 (14)	0.0642 (14)	0.0596 (13)	−0.0356 (12)	0.0058 (11)	−0.0240 (11)
C4	0.0488 (10)	0.0468 (10)	0.0546 (11)	−0.0148 (8)	0.0069 (8)	−0.0138 (9)
C5	0.0699 (13)	0.0536 (12)	0.0425 (10)	−0.0211 (10)	0.0040 (9)	−0.0148 (9)
C6	0.0748 (14)	0.0525 (11)	0.0439 (10)	−0.0286 (10)	−0.0008 (9)	−0.0140 (9)
N7	0.0560 (9)	0.0513 (9)	0.0379 (8)	−0.0184 (7)	0.0023 (7)	−0.0149 (7)
C8	0.0495 (10)	0.0469 (10)	0.0418 (9)	−0.0143 (8)	0.0008 (8)	−0.0143 (8)
C9	0.0599 (12)	0.0559 (12)	0.0440 (10)	−0.0218 (10)	0.0040 (9)	−0.0120 (9)
C10	0.0505 (11)	0.0601 (12)	0.0412 (10)	−0.0129 (9)	0.0018 (8)	−0.0147 (9)
N11	0.0625 (10)	0.0618 (11)	0.0394 (8)	−0.0210 (9)	0.0019 (7)	−0.0191 (8)
N12	0.0507 (9)	0.0448 (9)	0.0421 (8)	−0.0160 (7)	0.0009 (7)	−0.0137 (7)
C13	0.0544 (11)	0.0555 (12)	0.0512 (11)	−0.0147 (9)	−0.0053 (9)	−0.0143 (9)
C14	0.0725 (14)	0.0630 (14)	0.0462 (11)	−0.0218 (11)	−0.0067 (10)	−0.0158 (10)
C15	0.0695 (13)	0.0582 (12)	0.0453 (10)	−0.0192 (10)	0.0069 (9)	−0.0214 (9)
C16	0.0543 (11)	0.0469 (10)	0.0482 (10)	−0.0163 (9)	0.0060 (8)	−0.0158 (8)
C17	0.0590 (14)	0.090 (2)	0.0817 (19)	−0.0015 (14)	−0.0105 (13)	−0.0359 (16)
C18	0.0598 (14)	0.0768 (18)	0.0707 (16)	−0.0045 (12)	−0.0019 (12)	−0.0283 (14)
C19	0.0724 (15)	0.0813 (17)	0.0406 (11)	−0.0231 (13)	0.0045 (10)	−0.0179 (11)
Br20	0.0813 (2)	0.06456 (19)	0.06563 (19)	−0.03669 (15)	0.01681 (13)	−0.01529 (13)

Geometric parameters (Å, º)

C1—C2	1.390 (3)	C10—C19	1.496 (3)
C1—C6	1.392 (3)	N12—C13	1.380 (3)
C1—N7	1.421 (3)	N12—C16	1.391 (3)
C2—C3	1.379 (4)	C13—C14	1.357 (4)
C2—H2	0.9300	C13—C17	1.495 (4)
C3—C4	1.380 (3)	C14—C15	1.414 (4)
C3—H3	0.9300	C14—H14	0.9300
C4—C5	1.371 (3)	C15—C16	1.358 (3)
C4—Br20	1.904 (2)	C15—H15	0.9300
C5—C6	1.390 (3)	C16—C18	1.481 (4)
C5—H5	0.9300	C17—H17A	0.9600
C6—H6	0.9300	C17—H17B	0.9600
N7—C8	1.371 (3)	C17—H17C	0.9600
N7—N11	1.374 (2)	C18—H18A	0.9600
C8—C9	1.365 (3)	C18—H18B	0.9600
C8—N12	1.409 (3)	C18—H18C	0.9600
C9—C10	1.405 (3)	C19—H19A	0.9600
C9—H9	0.9300	C19—H19B	0.9600
C10—N11	1.321 (3)	C19—H19C	0.9600
C2—C1—C6	118.9 (2)	C13—N12—C8	125.24 (19)
C2—C1—N7	118.14 (19)	C16—N12—C8	125.32 (18)
C6—C1—N7	122.90 (18)	C14—C13—N12	107.0 (2)
C3—C2—C1	120.7 (2)	C14—C13—C17	131.7 (2)
C3—C2—H2	119.6	N12—C13—C17	121.3 (2)
C1—C2—H2	119.6	C13—C14—C15	108.7 (2)
C2—C3—C4	119.5 (2)	C13—C14—H14	125.6
C2—C3—H3	120.2	C15—C14—H14	125.6
C4—C3—H3	120.2	C16—C15—C14	107.6 (2)
C5—C4—C3	120.9 (2)	C16—C15—H15	126.2
C5—C4—Br20	119.27 (18)	C14—C15—H15	126.2
C3—C4—Br20	119.80 (17)	C15—C16—N12	107.4 (2)
C4—C5—C6	119.7 (2)	C15—C16—C18	131.0 (2)
C4—C5—H5	120.2	N12—C16—C18	121.6 (2)
C6—C5—H5	120.2	C13—C17—H17A	109.5
C5—C6—C1	120.22 (19)	C13—C17—H17B	109.5
C5—C6—H6	119.9	H17A—C17—H17B	109.5
C1—C6—H6	119.9	C13—C17—H17C	109.5
C8—N7—N11	109.87 (17)	H17A—C17—H17C	109.5
C8—N7—C1	131.61 (17)	H17B—C17—H17C	109.5
N11—N7—C1	118.51 (17)	C16—C18—H18A	109.5
C9—C8—N7	107.56 (18)	C16—C18—H18B	109.5
C9—C8—N12	129.0 (2)	H18A—C18—H18B	109.5
N7—C8—N12	123.44 (18)	C16—C18—H18C	109.5
C8—C9—C10	105.4 (2)	H18A—C18—H18C	109.5
C8—C9—H9	127.3	H18B—C18—H18C	109.5
C10—C9—H9	127.3	C10—C19—H19A	109.5
N11—C10—C9	111.16 (19)	C10—C19—H19B	109.5
N11—C10—C19	120.9 (2)	H19A—C19—H19B	109.5
C9—C10—C19	127.9 (2)	C10—C19—H19C	109.5
C10—N11—N7	106.00 (18)	H19A—C19—H19C	109.5
C13—N12—C16	109.31 (18)	H19B—C19—H19C	109.5
C6—C1—C2—C3	0.4 (4)	C9—C10—N11—N7	−0.9 (3)
N7—C1—C2—C3	−178.6 (2)	C19—C10—N11—N7	179.9 (2)
C1—C2—C3—C4	−0.3 (4)	C8—N7—N11—C10	0.7 (2)
C2—C3—C4—C5	0.2 (4)	C1—N7—N11—C10	179.52 (19)
C2—C3—C4—Br20	178.4 (2)	C9—C8—N12—C13	−88.5 (3)
C3—C4—C5—C6	−0.4 (4)	N7—C8—N12—C13	92.2 (3)
Br20—C4—C5—C6	−178.54 (19)	C9—C8—N12—C16	96.0 (3)
C4—C5—C6—C1	0.5 (4)	N7—C8—N12—C16	−83.3 (3)
C2—C1—C6—C5	−0.5 (4)	C16—N12—C13—C14	−0.3 (3)
N7—C1—C6—C5	178.4 (2)	C8—N12—C13—C14	−176.3 (2)
C2—C1—N7—C8	174.1 (2)	C16—N12—C13—C17	−179.8 (3)
C6—C1—N7—C8	−4.8 (4)	C8—N12—C13—C17	4.1 (4)
C2—C1—N7—N11	−4.4 (3)	N12—C13—C14—C15	−0.1 (3)
C6—C1—N7—N11	176.7 (2)	C17—C13—C14—C15	179.4 (3)
N11—N7—C8—C9	−0.3 (3)	C13—C14—C15—C16	0.4 (3)
C1—N7—C8—C9	−178.9 (2)	C14—C15—C16—N12	−0.6 (3)
N11—N7—C8—N12	179.10 (19)	C14—C15—C16—C18	178.5 (3)
C1—N7—C8—N12	0.5 (4)	C13—N12—C16—C15	0.5 (3)
N7—C8—C9—C10	−0.2 (3)	C8—N12—C16—C15	176.6 (2)
N12—C8—C9—C10	−179.6 (2)	C13—N12—C16—C18	−178.6 (2)
C8—C9—C10—N11	0.7 (3)	C8—N12—C16—C18	−2.6 (3)
C8—C9—C10—C19	179.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···pyrrole-ring	0.93	2.46	3.317 (3)	153
C9—H9···pyrrole-ring^i	0.93	2.64	3.536 (3)	162
C19—H19B···bromophenyl-ring^ii	0.96	2.97	3.612 (3)	125
C15—H15···Br20^iii	0.93	3.16	4.022 (3)	155

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