Vol. 25, No. 17 (2013)
Synthesis, Crystal and Supermolecular Structure of Substituted 1H-Pyrazol-5(4H)-one 9953
Yield, 73.8 %. m.p. 523-524 K. Several yellow block-like crystals
suitble for X-ray diffraction studies were obtained by slow
evaporation from a solution of dichloromethane at room tempe-
rature for about two weeks. Anal. calcd. (%) for C25H22N4O2:
C, 73.14; H, 5.41; N, 13.66. Found (%): C, 73.29; H, 5.58; N, 13.12.
X-Ray structure determination: The single crystal of
the title compound with approximate dimensions of 0.50 mm
× 0.20 mm × 0.15 mm was placed on a Bruker Smart 1000
diffractmeter equipped withApex CCD area detector. The diff-
raction data were collected using a graphite monochromated
MoKα radiation (λ = 0.071073 nm) at 298(2) K. The LP factor
and semi-empiriccal absorption corrections were applied to
the intensity data. The structure was solved by using the
program SHELXS-97 and difference Fourier techniques and
refined by full-matrix least-squares method on F2 using
SHELXL-97. The non-hydrogen atoms were refined aniso-
tropically. Hydrogen atoms were added theoretically. The data
collection and refinements of the title compound was given in
Table-1.
the pyrazole alkone ring. The ν(C-N) and ν(N-H) absorption
bands of pyrazole ring are at 1384 cm-1 and 3059 cm-1, respec-
tively. The strong IR bands at 1616 and 1589 cm-1 are assigned
to the ν(C=N) of the pyrazole ring and the alkyl chain.
Crystal structure description: X-ray crystallographic
analysis reveals the crystal structure of the title compound.
The bond lengths and bond angles are summarized in Tables
3 and 4. The ORTEP representation of the title compound is
shown in Fig. 1. The title compound crystallizes in the triclinic
system, space group P-1 and the unit cell contains two crysta-
llographically independent but chemically identical molecules
(moleculesA and B, Fig. 1) consisting of a pyrazole ring, three
benzene rings and a C=N-O group, etc. The dihedral angles
between the central pyrazole (N1-N2-C1) and the benzene
rings (C5-C10), (C12-C17) and (C18-C23) in molecules A
are 31.73°, 66.29° and 48.77°, respectively. However, the
dihedral angles between another central pyrazole (N5-N6-C26)
and the related benzene rings (C30-C35), (C37-C42) and (C43-
C48) molecules B are 37.02°, 71.93° and 60.75°, respectively.
Consequently, the two molecular units are of distinct difference
in structure.
TABLE-1
CRYSTAL DATA AND STRUCTURE REFINEMENT
FOR THE TITLE COMPOUND
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
C25H22N4O2
410.47
298(2)
0.71073
Triclinic
P-1
a = 9.5375(12), b = 11.2824(13),
c = 20.545(2)
α = 97.3970(10), β = 92.0430(10),
Cell dimensions (Å)°
γ = 99.280(2)
2160.1(4)
4
Volume (Å3)
Z
Density (calculated) (mg/m3) 1.262
Absorption coefficient (mm-1) 0.082
Fig. 1. Molecular structure of title compound with the atomic numbering.
Displacement ellipsoids for non-H atoms are drawn at the 30%
probability level
F(000)
Index ranges
Reflections collected/unique
Data/restraints/parameters
Goodness of fit indicator
R [I > 2σ(I)]
864
-1 < h < 11, -13 < k <10, -24 < l < 22
10989/7534 [R(int) = 0.0518]
7534/0/559
Supramolecular interaction: In the crystal structure,
there are two strong intramolecular N3-H3···O1 and N7-
H7···O3 hydrogen bonds in molecules A and B between the
-NH groups of the -C=NH groups and the ketone oxygen
atoms of pyrazolone groups, which generate six-membered
S(6) ring motifs (Table-5)15-18. In a pair of independent mole-
cules A and B, each molecule A interlinks two neighbouring
molecules B into a 1D infinite chain through six intermolecular
O2-H2···N6, C29-H29A···O2, C35-H35···N4, O4-H4···N2,
C4-H4A···O4 and C10-H10···N8 hydrogen bonds. And each
molecule B interlinks two neighboring molecules A into the
other 1D infinite chain in the same way (Fig. 2). In addition,
two formed chains are held together by intermolecular C16-
H16···O2, C23-H23···O3, C39-H39···O4 and C44-H44···O1
hydrogen bonds to form a 1D infinite dual chains (Fig. 3). Further-
more, this dual chains are further stabilized by intermolecular
0.818
R1 = 0.0548, wR2 = 0.0697
0.156 and -0.155 e.Å-3
Largest diff. peak and hole
RESULTS AND DISCUSSION
FT-IR spectra: Key IR data of the title compound is given
in Table-2. The IR spectrum exhibits several resonances in the
4000-500 cm-1 region. In the Table-2, it is clear that the title
compound has obvious ν(O-H) absorption band at 3217 cm-1,
which indicates that the title compound exists with the imine
enol type structure not the enamine ketonic. The absorption
bands which appeared near the 2964, 2875 and 2292 cm-1 are
assigned to ν(C-H) of the methyl or methylene. The absorption
band of the title compound at 1732 cm-1 assigns to ν(C=O) to
TABLE-2
KEY INFRARED ABSORPTION BANDS (cm–1) OF THE TITLE COMPOUND
Compound
C25H22N4O2
ν(O-H)
3217
ν(C-H)
2964, 2875, 2292
ν(C=O)
1732
ν(C-N)
1384
ν(N-H)
3059
ν(C=N)
1616, 1589
Dong
