Y. Liu et al. / Journal of Molecular Structure 1184 (2019) 532e537
533
properties and theoretical analysises of acylhydrazones are rarely,
which provide a chance for us to carry on this research. The ex-
pected results of the study can provide theoretical basis for the
pharmacological research and industrial application of the
acylhydrazones.
In this study, the 2-[(4-nitro-benzoyl)-hydrazone]-propionic
acid (C10H9O5N3, Scheme 1) was synthesized, and the structure was
characterized by X-ray diffractometer (XRD), IR, and elemental
analysis. The low-temperature heat capacities and the standard
molar enthalpy of formation of the C10H9O5N3 were measured by
adiabatic calorimetry and combustion calorimetry, respectively.
The optimized molecular structure, frontier molecular orbitals
(HOMO and LUMO), and molecular electrostatic potential (MEP)
analysis of the title compound were investigated by using the DFT
method at the B3LYP/6-31G(d,p) level.
from Fig. 1, the whole heat capacity curve increases with the in-
crease of temperature from 78 to 400 K, and no anomaly, which
indicates that the structure of the substance is stable in the whole
temperature region. All points of experimental molar heat capac-
ities (Cp, m) versus reduced temperatures (X) were fitted with a
polynomial equation by means of the least-squares method. The
correlation coefficient for the fitting R2 equals 0.99998, the fitting
equation as follows:
.ꢀ
ꢁ
Cp;m J,Kꢁ1,molꢁ1 ¼ 252:947 þ 198:770X ꢁ 71:519X2
ꢁ 15:513X3 þ 22:146X4
(1)
In which X ¼ (T-239)/161 is the reduced temperature, X ¼ [T -
(Tmax þ Tmin)/2]/[(Tmax - Tmin)/2], T is the experimental tempera-
ture; Tmax and Tmin are the upper and lower limits of the temper-
ature region, respectively.
Smoothed values of the molar heat capacities were obtained
based on the fitted polynomial equation (1). The relative deviations
between the experimental values and the smoothed values are
0.4% except for few points. The other fundamental thermody-
namic functions of the sample relative to the standard reference
temperature 298.15 K can been calculated according to the ther-
modynamic equations (2)e(4). The results are tabulated in Table 2
at the intervals of 5 K.
2. Experimental section
2.1. Preparation of C10H9O5N3
4-nitro-benzoylhydrazide and pyruvic acid were commercially
available and used as received. C10H9O5N3 was synthesized by
literature method with minor modifications [34]. 4-nitro-ben-
zoylhydrazide (2.325 g, 10 mmol) was dissolved in absolute ethyl
alcohol (30 mL), and stirred until entirely dissolved. Then, pyruvic
acid (1.232 g, 14 mmol) was slowly added to the above transparent
solution via a dropping funnel. The mixture solution was heated
under reflux for 2 h. Finally, the precipitate was filtered in vacuo to
give a pale yellow powder. The powder was recrystallized from
ethanol, and the yellow product was obtained. Yield: 71.62%. Anal.
calcd for C10H9N3O5: C, 47.81; H, 3.61; N, 16.73. Found: C, 47.92; H,
3.67; N, 16.64. IR (KBr, cmꢁ1): 1690, 1570, 1530, 1490, 1270, 1030,
854, 791, 715.
T
ð
ðHT ꢁ H298:15Þ ¼
ðST ꢁ S298:15Þ ¼
Cp;mdT
(2)
(3)
(4)
298:15
T
ð
C
p;m,Tꢁ1dT
298:15
T
T
ð
ð
2.2. Preparation of the compound [C10H9O5N3·H2O]n
ðGT ꢁ G298:15Þ ¼
Cp;mdT ꢁ T,
C
p;m,Tꢁ1dT
The C10H9O5N3 (0.10 g, 0.40 mmol) was dissolved in mixed so-
lution of C2H5OH and H2O (Vethanol:Vwater ¼ 1:1, 20 mL). Then the
solution was filtered, and the filtrate was naturally evaporated at
room temperature. After three days, the yellow columnar crystals
were collected, and dried in the air (Yield: 52.21%). The crystal
structure of above crystal was determined by the single crystal X-
ray diffraction. Crystal data: [C10H9O5N3$H2O]n, Monoclinic, P 21,
a ¼ 6.5892(17) Å, b ¼ 11.781(3) Å, c ¼ 7.590(2) Å, V ¼ 587.8(3) Å3,
Z ¼ 2. The asymmetric unit of compound contains one C10H9O5N3
molecule and one lattice H2O molecule (Fig. S1). The detailed
crystallographic data were summarized in Table S1. Selected bond
lengths and angles were listed in Tables S2-S3, Supporting Infor-
298:15
298:15
3.2. Standard molar enthalpy of formation
The constant-volume energy of combustion of C10H9O5N3 was
determined using an RBC-II precision rotating bomb combustion
calorimeter. The DcU of the C10H9O5N3 can be calculated from Eq
(5). The experimental results are listed in Table 3.
ꢁ
DcU=J,gꢁ1 ¼ ðεcalor
,
DT ꢁ QNi ꢁ QHNO3Þ=W
(5)
mation.
CCDC
number
is
1578867
for
compound
where DcU/(J$gꢁ1) is the constant-volume energy of combustion of
[C10H9O5N3$H2O]n.
the sample; εcalor/(J$Kꢁ1) is the energy equivalent of the oxygen-
bomb calorimeter;
the mass of the sample.sa
the experimental number; xi is a single value obtained from a series
of measurements; xis the mean value of the results.
D
T/K is the corrected temperature rise; W/g is
qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
P
3. Results and discussion
3.1. Low-temperature heat capacities
n
¼
i¼1ðx ꢁ xÞ=nðn ꢁ 1Þ, in which n is
At T ¼ 298.15 K, the pressure quotient of the constant-volume
energy of combustion: (vu/vp)T ¼ ꢁ0.2 J$gꢁ1$MPaꢁ1 [35]. Consid-
ering that the pressure was corrected from 2.50 to 0.1 MPa,
The experimental results of low-temperature heat capacities of
the sample are listed in Table 1 and plotted in Fig. 1. As can be seen
D
P ¼ ꢁ2.49 MPa, the change of the constant-volume energy of
combustion of the sample
D( .
DcU) was calculated to 0.50 J$gꢁ1
Therefore, the standard (pꢀ ¼ 0.1 MPa) constant-volume energy of
combustion for
C
10H9O5N3 was corrected to be DcUꢀ ¼ -
(18161.35 49.79) J$gꢁ1 þ 0.50 J$gꢁ1 ¼ -(18160.85 49.79) J$gꢁ1
,
and DcUꢀm ¼ - (4558.37 12.50) kJ$molꢁ1
.
Scheme 1. Structure of C10H9O5N3.
The standard molar enthalpy of combustion,DcHꢀm, of C10H9O5N3
Liu, Yongliang
