Synthesis and structure of a 1:1 1-phenyl­semicarbazide–1-phenyl­pyrazolidin-3-one cocrystal

Muthu, S.; Siji, V.L.; Sreejith, S.S.; Sithambaresan, M.

doi:10.1107/S2056989026002550

research communications

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ISSN: 2056-9890

Volume 82| Part 4| April 2026| Pages 371-374

https://doi.org/10.1107/S2056989026002550

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Synthesis and structure of a 1:1 1-phenylsemicarbazide–1-phenylpyrazolidin-3-one cocrystal

S. Muthu,^a,^b V. L. Siji,^c,^b ^* S. S. Sreejith ^d and M. Sithambaresan ^e ^*

^aDepartment of Chemistry, Sree Narayana College, Varkala, India, ^bDepartment of Chemistry, Mahatma Gandhi College, Thiruvananthapuram, India, ^cDepartment of Chemistry, All Saints' College, Thiruvananthapuram, India, ^dDepartment of Chemical Oceanography, Lake Side Campus, Cochin University of Science & Technology, Kochi, India, and ^eDepartment of Chemistry, Faculty of Science, Eastern University, Sri Lanka, Chenkalady, Sri Lanka
^*Correspondence e-mail: [email protected], [email protected]

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 16 February 2026; accepted 10 March 2026; online 17 March 2026)

The title cocrystal, C₇H₉N₃O·C₉H₁₀N₂O, was obtained by the cocrystallization of 1-phenylsemicarbazide (A) and 1-phenylpyrazolidin-3-one (B) in a 1:1 molar ratio from methanol solution. The structure features a gauche arrangement about the N—N bond in the semicarbazide fragment and a twisted conformation of the pyrazolidinone ring. In the extended structure, the molecules are linked by A → A and B → A N—H⋯O hydrogen bonds, supplemented by C—H⋯π contacts to generate a three-dimensional supramolecular framework.

Keywords: crystal structure; cocrystal; gauche conformation.

CCDC reference: 2378160

1. Chemical context

Semicarbazide (CH₅N₃O) is the diamino derivative of urea and contains three N atoms and a carbonyl group as potential hydrogen-bonding sites and for coordination with metal centers (Asifa et al., 2021 ). It forms semicarbazones on condensation with aldehydes/ketone (Reena et al., 2008 ; Reena & Kurup, 2010 ). Consequently, semicarbazide and its derivatives have found extensive utility in the synthesis of compounds with biological and industrial relevance. Beyond its biological applications, semicarbazide derivatives have also been reported to act as effective corrosion inhibitors in aqueous environments (Olasunkanmi et al., 2020 ).

In the field of crystal engineering, cocrystals defined as single-phase crystalline materials comprising two or more neutral molecular species have long been exploited to tune physicochemical attributes while preserving the molecular identity of active components (Taylor & Day, 2018 ). A recent review reaffirms that cocrystallization remains a powerful approach to modulate API properties, with modern design strategies expanding via techniques such as spray drying, hot-melt extrusion and supercritical fluid processing (Sakhiya & Borkhataria 2024 ). Rode and colleagues demonstrated the potential of flavonoid-based cocrystal and coamorphous systems (Rode et al., 2024 ).

As part of our studies in this area, we now describe the synthesis and structure of the title 1:1 cocrystal formed between 1-phenylsemicarbazide (A) and 1-phenylpyrazolidin-3-one (B), C₇H₉N₃O·C₉H₁₀N₂O, (I), Fig. 1.

Figure 1
The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level.

2. Structural commentary

The semicarbazide–aromatic linkage in molecule A of (I) displays a pronounced deviation from coplanarity, as shown by the C1—N2—N3—C2 torsion angle of −99.2 (2)°, indicating a gauche arrangement about the N—N bond. The O1—C1—N2—N3 torsion of 177.2 (1)° confirms an anti-periplanar relationship between the carbonyl oxygen atom and the N—N linkage, while the N1—C1—N2—N3 torsion angle of −1.9 (2)° supports near planarity at C1 and sp² hybridization at N1. In the side chain, C3—C2—N3—N2 [−167.0 (1)°] is close to anti-periplanar, whereas C7—C2—N3—N2 [17.9 (2)°] indicates a gauche disposition of the phenyl substituent.

The pyrazolidinone ring (C8–C10/N4/N5) in molecule B adopts a twisted conformation about C10—C9, with Cremer–Pople parameters Q(2) = 0.229 (2) Å and Φ(2) = 263.7 (5)°. The pseudorotation parameters P = 65.5 (4)° and τ_M = 23.9 (2)° (Jia et al., 2008 ) confirm this geometry. The mean absolute torsion angle (17.6°) and atomic deviations in the ring (–0.142 to +0.132 Å) indicate moderate non-planarity, in line with reported pyrazolidinone structures (Domenicano et al., 1975 ). The pyrazolidinone and phenyl (C11–C16) rings are inclined by 54.42 (12)°, producing a significant out-of-plane arrangement.

3. Supramolecular features

The extended structure of (I) features an extensive network of intermolecular interactions, including N—H⋯O hydrogen bonds (Table 1) and C—H⋯π contacts, which collectively underpin its efficient packing and structural cohesion.

Table 1
Hydrogen-bond geometry (Å, °)

Cg2 and Cg3 are the centroids of the C11–C16 and C2–C7 rings, respectively

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O1ⁱ	0.93 (2)	2.09 (2)	3.0164 (17)	178 (2)
N1—H1A⋯O2ⁱⁱ	0.87 (2)	2.12 (2)	2.9645 (18)	161 (2)
N2—H2N⋯O1ⁱⁱⁱ	0.88 (2)	2.09 (2)	2.9486 (17)	166 (2)
N3—H3N⋯O2ⁱⁱⁱ	0.84 (2)	2.15 (2)	2.9641 (19)	161 (2)
N4—H4N⋯O1	0.88 (2)	2.08 (2)	2.9471 (19)	167 (2)
C4—H4⋯Cg2^iv	0.93	2.77	3.653 (3)	158
C9—H9B⋯Cg3^v	0.97	2.64	3.510 (2)	149
Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

Five significant hydrogen bonds were identified, featuring donor–acceptor (D⋯A) distances shorter than 3.05 Å. These hydrogen bonds all involve N—H donors and carbonyl oxygen atom acceptors (Fig. 2): the strong, near-linear interactions such as N1—H1B⋯O1 and N4—H4N⋯O1 are consistent with hydrogen-bonding motifs typical of semicarbazide-based structures, contributing to a well-defined supramolecular framework (Kurup et al., 2011 ; Kunnath et al., 2026 ).

Figure 2
Hydrogen bonds in the crystal packing of (I) shown as dashed lines.

Complementing these, C—H⋯π interactions consolidate the structure: these interactions were identified by short hydrogen-to-centroid distances (< 3.0 Å) and favorable angular geometries (Desiraju & Steiner, 1999 ). Two notable C—H⋯π contacts include C4—H4⋯Cg2 with an H⋯Cg distance of 2.77 Å and C9—H9B⋯Cg3 with a shorter H⋯Cg distance of 2.64 Å. The latter exhibits a more linear approach, facilitating an effective perpendicular hydrogen-bonding interaction to the π-system (Mahadevi & Sastry, 2016 ). These C—H⋯π contacts further enhance the cohesion of the structure of (I) but there are no significant π–π interactions present in the crystal (Fig. 3).

Figure 3
The packing of (I) viewed down [100].

4. Hirshfeld surface analysis

Hirshfeld surface analysis and the associated two-dimensional fingerprint plots were generated using CrystalExplorer (Spackman et al., 2021 ). The Hirshfeld surfaces were mapped over the normalized contact distance (d_norm), shape index, curvedness, and fragment patches for both the 1-phenylsemicarbazide and 1-phenylpyrazolidin-3-one components (see supplementary Figure). The d_norm surfaces of both molecules exhibit bright-red spots that signify close intermolecular contacts (shorter than the sum of van der Waals radii). For the 1-phenylsemicarbazide moiety, these red regions are concentrated around the amine donors (N1, N2) and the carbonyl acceptor (O1). Similarly, the 1-phenylpyrazolidin-3-one surface shows deep-red depressions near the N4 donor and O2 acceptor atoms. These features confirm the presence of the strong N—H⋯O hydrogen bonding network identified in the crystal structure analysis.

The two-dimensional fingerprint plots (Fig. 4) provide a quantitative comparison of the intermolecular interactions for the two distinct units. The surface of A is dominated by H⋯H contacts (47.6%), followed by C⋯H/H⋯C contacts (24.1%), which correspond to the C—H⋯π interactions. The O⋯H/H⋯O interactions, representing the strong hydrogen bonds, make a significant contribution of 23.5% and appear as sharp, distinct spikes. In B, a higher dominance of H⋯H contacts (54.7%) can be seen and a similar contribution from C⋯H/H⋯C interactions (25.7%). However, the O⋯H/H⋯O interactions contribute less (13.3%) compared to the semicarbazide unit.

Figure 4
Two-dimensional fingerprint plots for (a) 1-phenylsemicarbazide and (b) 1-phenylpyrazolidin-3-one, delineated into specific intermolecular contacts with their percentage contributions to the Hirshfeld surface area.

5. Synthesis and crystallization

Compound (I) was formed by mixing equimolar quantities of 1-phenylsemicarbazide (0.1512 g, 1 mmol) and 1-phenylpyrazolidin-3-one (0.1621 g, 1 mmol) in methanol (20 ml) and refluxing with stirring until a clear solution was obtained. The hot solution was filtered to remove any insoluble material and allowed to cool slowly to room temperature. Brown block-shaped crystals of (I) were obtained after slow evaporation of the solvent over several days.

FT IR (cm⁻¹) 3291 (N—H stretch); 3190 (aromatic C—H stretch); 1693 (amine N—H stretch); 1663 (C=O stretch); 1427 (pyrazolidinone C=N stretch); 1282 (aromatic C=N stretch); 1024 (semicarbazide N—N stretch). The red shift for the C=O bond from its typical position substantiates the hydrogen bonding in the cocrystal (Siji et al., 2010a ,b ). UV/visible (methanol), 245 and 287 nm due to π–π* transitions of the aromatic rings. For figures of the IR, UV/visible and ¹H and ¹³C NMR spectra of (I), see supporting information.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The N-bound hydrogen atoms were located in difference maps and freely refined. The C-bound H atoms were placed geometrically and refined using a riding model.

Table 2
Experimental details

Crystal data
Chemical formula	C₇H₉N₃O·C₉H₁₀N₂O
M_r	313.36
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	304
a, b, c (Å)	7.3651 (6), 8.8906 (5), 13.3791 (10)
α, β, γ (°)	76.121 (2), 88.579 (3), 73.108 (2)
V (Å³)	812.84 (10)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.09
Crystal size (mm)	0.35 × 0.21 × 0.09

Data collection
Diffractometer	Bruker D8 Venture Diffractometer
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.535, 0.745
No. of measured, independent and observed [I > 2σ(I)] reflections	32158, 3069, 2566
R_int	0.063
(sin θ/λ)_max (Å⁻¹)	0.609

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.123, 1.06
No. of reflections	3063
No. of parameters	223
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.26
Computer programs: APEX4 and SAINT (Bruker, 2021 ), SHELXT2018/2 (Sheldrick, 2015a ), SHELXL2019/3 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), Mercury (Macrae et al., 2020 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 2378160

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989026002550/hb8196sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989026002550/hb8196Isup3.hkl

Additional Figures. DOI: https://doi.org/10.1107/S2056989026002550/hb8196sup4.docx

Supporting information file. DOI: https://doi.org/10.1107/S2056989026002550/hb8196Isup4.cml

checkCIF report

Computing details top

1-Phenylsemicarbazide–1-phenylpyrazolidin-3-one (1/1) top

Crystal data top

C₇H₉N₃O·C₉H₁₀N₂O	Z = 2
M_r = 313.36	F(000) = 332
Triclinic, P1	D_x = 1.280 Mg m⁻³
a = 7.3651 (6) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.8906 (5) Å	Cell parameters from 9264 reflections
c = 13.3791 (10) Å	θ = 2.6–25.6°
α = 76.121 (2)°	µ = 0.09 mm⁻¹
β = 88.579 (3)°	T = 304 K
γ = 73.108 (2)°	Block, brown
V = 812.84 (10) Å³	0.35 × 0.21 × 0.09 mm

Data collection top

Bruker D8 Venture Diffractometer	2566 reflections with I > 2σ(I)
Radiation source: fine focus sealed tube	R_int = 0.063
φ and ω scans	θ_max = 25.7°, θ_min = 2.9°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −8→8
T_min = 0.535, T_max = 0.745	k = −10→10
32158 measured reflections	l = −16→16
3069 independent reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.045	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.123	w = 1/[σ²(F_o²) + (0.0602P)² + 0.2037P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
3063 reflections	Δρ_max = 0.22 e Å⁻³
223 parameters	Δρ_min = −0.26 e Å⁻³
0 restraints

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.2118 (2)	0.60592 (16)	0.52900 (10)	0.0311 (3)
C2	−0.0439 (2)	0.79617 (18)	0.69126 (12)	0.0372 (3)
C3	−0.1379 (2)	0.9337 (2)	0.72492 (14)	0.0498 (4)
H3	−0.197869	1.029765	0.677228	0.060*
C4	−0.1425 (2)	0.9279 (3)	0.82926 (16)	0.0589 (5)
H4	−0.206428	1.020272	0.851105	0.071*
C5	−0.0538 (3)	0.7872 (3)	0.90105 (15)	0.0577 (5)
H5	−0.056367	0.784348	0.971004	0.069*
C6	0.0385 (3)	0.6513 (2)	0.86799 (15)	0.0544 (5)
H6	0.098617	0.555851	0.916145	0.065*
C7	0.0435 (2)	0.6540 (2)	0.76410 (14)	0.0455 (4)
H7	0.105433	0.560428	0.743041	0.055*
C8	0.3195 (2)	0.0381 (2)	0.66850 (14)	0.0480 (4)
C9	0.3529 (3)	−0.0688 (2)	0.77620 (15)	0.0605 (5)
H9A	0.486672	−0.126278	0.791363	0.073*
H9B	0.281541	−0.146969	0.785807	0.073*
C10	0.2827 (4)	0.0488 (3)	0.84304 (16)	0.0755 (7)
H10A	0.152873	0.054819	0.861230	0.091*
H10B	0.362110	0.016182	0.905826	0.091*
C11	0.4384 (2)	0.26709 (17)	0.80707 (12)	0.0382 (4)
C12	0.4607 (3)	0.2703 (2)	0.90964 (13)	0.0470 (4)
H12	0.385872	0.227717	0.958919	0.056*
C13	0.5924 (3)	0.3359 (2)	0.93827 (15)	0.0617 (5)
H13	0.608361	0.335093	1.007139	0.074*
C14	0.7001 (4)	0.4023 (3)	0.86646 (17)	0.0829 (8)
H14	0.788846	0.446994	0.886201	0.100*
C15	0.6767 (3)	0.4026 (3)	0.76518 (17)	0.0762 (7)
H15	0.748700	0.449360	0.716113	0.091*
C16	0.5478 (3)	0.3346 (2)	0.73500 (13)	0.0502 (4)
H16	0.534571	0.334117	0.666125	0.060*
N1	0.3338 (2)	0.68854 (16)	0.53556 (11)	0.0399 (3)
N2	0.02993 (19)	0.66632 (17)	0.55207 (11)	0.0439 (3)
N3	−0.02852 (19)	0.80919 (16)	0.58501 (11)	0.0420 (3)
N4	0.2967 (3)	0.18810 (18)	0.67682 (12)	0.0585 (5)
N5	0.2939 (2)	0.20624 (18)	0.77994 (11)	0.0529 (4)
O1	0.25943 (14)	0.47328 (12)	0.50354 (8)	0.0368 (3)
O2	0.3102 (2)	−0.00009 (15)	0.58679 (10)	0.0601 (4)
H1B	0.460 (3)	0.641 (3)	0.5246 (17)	0.072*
H1A	0.303 (3)	0.777 (3)	0.5578 (17)	0.072*
H2N	−0.052 (3)	0.614 (3)	0.5465 (17)	0.072*
H3N	−0.115 (3)	0.879 (3)	0.5449 (18)	0.072*
H4N	0.267 (3)	0.273 (3)	0.6235 (18)	0.072*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0351 (8)	0.0324 (7)	0.0255 (7)	−0.0095 (6)	−0.0015 (5)	−0.0065 (5)
C2	0.0246 (7)	0.0426 (8)	0.0471 (9)	−0.0090 (6)	0.0004 (6)	−0.0171 (7)
C3	0.0372 (9)	0.0512 (10)	0.0570 (11)	0.0018 (7)	−0.0051 (7)	−0.0229 (8)
C4	0.0397 (9)	0.0741 (13)	0.0656 (12)	−0.0020 (9)	0.0045 (8)	−0.0403 (10)
C5	0.0451 (10)	0.0854 (14)	0.0469 (10)	−0.0208 (9)	0.0080 (8)	−0.0224 (10)
C6	0.0515 (10)	0.0601 (11)	0.0512 (11)	−0.0231 (9)	0.0024 (8)	−0.0044 (8)
C7	0.0422 (9)	0.0412 (9)	0.0555 (10)	−0.0134 (7)	0.0038 (7)	−0.0148 (7)
C8	0.0496 (10)	0.0431 (9)	0.0544 (10)	−0.0201 (7)	−0.0144 (8)	−0.0077 (7)
C9	0.0653 (12)	0.0539 (11)	0.0631 (12)	−0.0344 (9)	−0.0157 (9)	0.0068 (9)
C10	0.1078 (18)	0.0908 (16)	0.0520 (12)	−0.0705 (15)	0.0022 (11)	−0.0117 (11)
C11	0.0393 (8)	0.0336 (7)	0.0391 (8)	−0.0066 (6)	−0.0051 (6)	−0.0085 (6)
C12	0.0520 (10)	0.0540 (10)	0.0369 (9)	−0.0181 (8)	0.0031 (7)	−0.0119 (7)
C13	0.0833 (14)	0.0691 (12)	0.0412 (10)	−0.0337 (11)	−0.0108 (9)	−0.0142 (9)
C14	0.1059 (19)	0.1016 (18)	0.0610 (13)	−0.0729 (16)	−0.0196 (12)	−0.0022 (12)
C15	0.0874 (16)	0.0977 (17)	0.0542 (12)	−0.0617 (14)	−0.0031 (11)	0.0043 (11)
C16	0.0622 (11)	0.0532 (10)	0.0330 (8)	−0.0192 (8)	−0.0039 (8)	−0.0027 (7)
N1	0.0368 (7)	0.0382 (7)	0.0507 (8)	−0.0140 (6)	0.0053 (6)	−0.0184 (6)
N2	0.0330 (7)	0.0478 (8)	0.0601 (9)	−0.0121 (6)	0.0026 (6)	−0.0299 (7)
N3	0.0386 (7)	0.0398 (7)	0.0458 (8)	−0.0013 (6)	−0.0046 (6)	−0.0188 (6)
N4	0.0910 (12)	0.0433 (8)	0.0427 (8)	−0.0255 (8)	−0.0237 (8)	−0.0035 (6)
N5	0.0604 (9)	0.0597 (9)	0.0448 (8)	−0.0272 (7)	−0.0093 (7)	−0.0117 (7)
O1	0.0369 (6)	0.0357 (5)	0.0416 (6)	−0.0114 (4)	0.0025 (4)	−0.0157 (4)
O2	0.0730 (9)	0.0490 (7)	0.0625 (8)	−0.0192 (6)	−0.0141 (7)	−0.0182 (6)

Geometric parameters (Å, º) top

C1—O1	1.2554 (16)	C10—H10A	0.9700
C1—N1	1.3311 (19)	C10—H10B	0.9700
C1—N2	1.3489 (19)	C11—C16	1.380 (2)
C2—C7	1.389 (2)	C11—C12	1.394 (2)
C2—C3	1.391 (2)	C11—N5	1.416 (2)
C2—N3	1.403 (2)	C12—C13	1.372 (3)
C3—C4	1.384 (3)	C12—H12	0.9300
C3—H3	0.9300	C13—C14	1.365 (3)
C4—C5	1.376 (3)	C13—H13	0.9300
C4—H4	0.9300	C14—C15	1.369 (3)
C5—C6	1.372 (3)	C14—H14	0.9300
C5—H5	0.9300	C15—C16	1.379 (3)
C6—C7	1.384 (3)	C15—H15	0.9300
C6—H6	0.9300	C16—H16	0.9300
C7—H7	0.9300	N1—H1B	0.93 (2)
C8—O2	1.229 (2)	N1—H1A	0.87 (2)
C8—N4	1.326 (2)	N2—N3	1.3909 (18)
C8—C9	1.505 (3)	N2—H2N	0.88 (2)
C9—C10	1.508 (3)	N3—H3N	0.84 (2)
C9—H9A	0.9700	N4—N5	1.426 (2)
C9—H9B	0.9700	N4—H4N	0.88 (2)
C10—N5	1.475 (2)

O1—C1—N1	122.83 (13)	H10A—C10—H10B	108.8
O1—C1—N2	118.62 (13)	C16—C11—C12	118.72 (15)
N1—C1—N2	118.54 (13)	C16—C11—N5	122.61 (15)
C7—C2—C3	118.78 (15)	C12—C11—N5	118.47 (15)
C7—C2—N3	122.29 (14)	C13—C12—C11	120.35 (17)
C3—C2—N3	118.76 (15)	C13—C12—H12	119.8
C4—C3—C2	120.15 (17)	C11—C12—H12	119.8
C4—C3—H3	119.9	C14—C13—C12	120.53 (18)
C2—C3—H3	119.9	C14—C13—H13	119.7
C5—C4—C3	120.84 (17)	C12—C13—H13	119.7
C5—C4—H4	119.6	C13—C14—C15	119.57 (19)
C3—C4—H4	119.6	C13—C14—H14	120.2
C6—C5—C4	119.08 (17)	C15—C14—H14	120.2
C6—C5—H5	120.5	C14—C15—C16	120.87 (19)
C4—C5—H5	120.5	C14—C15—H15	119.6
C5—C6—C7	121.05 (17)	C16—C15—H15	119.6
C5—C6—H6	119.5	C15—C16—C11	119.93 (17)
C7—C6—H6	119.5	C15—C16—H16	120.0
C6—C7—C2	120.10 (16)	C11—C16—H16	120.0
C6—C7—H7	119.9	C1—N1—H1B	117.0 (13)
C2—C7—H7	119.9	C1—N1—H1A	122.8 (14)
O2—C8—N4	124.66 (16)	H1B—N1—H1A	120 (2)
O2—C8—C9	128.52 (16)	C1—N2—N3	120.99 (13)
N4—C8—C9	106.80 (16)	C1—N2—H2N	119.1 (14)
C8—C9—C10	103.49 (16)	N3—N2—H2N	119.9 (15)
C8—C9—H9A	111.1	N2—N3—C2	117.65 (13)
C10—C9—H9A	111.1	N2—N3—H3N	110.9 (15)
C8—C9—H9B	111.1	C2—N3—H3N	118.1 (15)
C10—C9—H9B	111.1	C8—N4—N5	114.89 (15)
H9A—C9—H9B	109.0	C8—N4—H4N	122.9 (14)
N5—C10—C9	105.18 (16)	N5—N4—H4N	121.5 (14)
N5—C10—H10A	110.7	C11—N5—N4	114.65 (14)
C9—C10—H10A	110.7	C11—N5—C10	117.83 (15)
N5—C10—H10B	110.7	N4—N5—C10	104.08 (14)
C9—C10—H10B	110.7

C7—C2—C3—C4	0.4 (2)	C12—C11—C16—C15	0.3 (3)
N3—C2—C3—C4	−174.90 (16)	N5—C11—C16—C15	175.19 (18)
C2—C3—C4—C5	0.4 (3)	O1—C1—N2—N3	177.20 (13)
C3—C4—C5—C6	−0.6 (3)	N1—C1—N2—N3	−1.9 (2)
C4—C5—C6—C7	0.1 (3)	C1—N2—N3—C2	−99.21 (17)
C5—C6—C7—C2	0.7 (3)	C7—C2—N3—N2	17.9 (2)
C3—C2—C7—C6	−0.9 (2)	C3—C2—N3—N2	−166.97 (14)
N3—C2—C7—C6	174.18 (14)	O2—C8—N4—N5	173.73 (17)
O2—C8—C9—C10	−160.94 (19)	C9—C8—N4—N5	−4.9 (2)
N4—C8—C9—C10	17.7 (2)	C16—C11—N5—N4	12.7 (2)
C8—C9—C10—N5	−23.4 (2)	C12—C11—N5—N4	−172.37 (14)
C16—C11—C12—C13	−1.6 (3)	C16—C11—N5—C10	135.77 (19)
N5—C11—C12—C13	−176.65 (16)	C12—C11—N5—C10	−49.3 (2)
C11—C12—C13—C14	1.6 (3)	C8—N4—N5—C11	119.86 (17)
C12—C13—C14—C15	−0.3 (4)	C8—N4—N5—C10	−10.3 (2)
C13—C14—C15—C16	−1.0 (4)	C9—C10—N5—C11	−107.49 (18)
C14—C15—C16—C11	1.0 (4)	C9—C10—N5—N4	20.7 (2)

Hydrogen-bond geometry (Å, º) top

Cg2 and Cg3 are the centroids of the C11–C16 and C2–C7 rings, respectively

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1ⁱ	0.93 (2)	2.09 (2)	3.0164 (17)	178 (2)
N1—H1A···O2ⁱⁱ	0.87 (2)	2.12 (2)	2.9645 (18)	161 (2)
N2—H2N···O1ⁱⁱⁱ	0.88 (2)	2.09 (2)	2.9486 (17)	166 (2)
N3—H3N···O2ⁱⁱⁱ	0.84 (2)	2.15 (2)	2.9641 (19)	161 (2)
N4—H4N···O1	0.88 (2)	2.08 (2)	2.9471 (19)	167 (2)
C4—H4···Cg2^iv	0.93	2.77	3.653 (3)	158
C9—H9B···Cg3^v	0.97	2.64	3.510 (2)	149

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

Acknowledgements

The authors thank the SAIF, IIT, Madras, India, for the data collection.

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research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Synthesis and structure of a 1:1 1-phenyl­semicarbazide–1-phenyl­pyrazolidin-3-one cocrystal

1. Chemical context

2. Structural commentary

3. Supra­molecular features

4. Hirshfeld surface analysis

5. Synthesis and crystallization

6. Refinement

Supporting information

Acknowledgements

References

research communications

Synthesis and structure of a 1:1 1-phenylsemicarbazide–1-phenylpyrazolidin-3-one cocrystal

3. Supramolecular features