Structural, spectral, electrochemistry, thermal properties and theoretical studies on 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro benzoylhydrazone

Article abstract of DOI:10.1016/j.molstruc.2014.07.062

The title compound 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro benzoylhydrazone (C₂₈H₂₄ClN₃O, M_r= 453.96) was synthesized by the reaction of 4-[N, N-di(4-tolyl)amino] benzaldehyde with 2-chlorobenzohydrazide, and its structure was characterized by IR, ¹H NMR, ¹³H NMR, high-resolution mass spectrometry and single-crystal X-ray diffraction. The crystal belongs to Monoclinic, space group P2(1)/n with a = 12.626(3), b = 12.609(3), c = 15.837(3) ?, β = 90.00(3)°, Z = 5, V = 2512.5(9) ?³, M_r= 453.95, Dc = 1.280 g/cm³, μ = 0.183 mm^-1, F(0 0 0) = 1024, R = 0.0432 and wR = 0.1087. X-ray analysis revealed that one of the benzene ring and acylhydrazone were essentially planar, the 2-chloro benzene ring and amide were non-planar, the torsion angles C(1)C(6)C(7)O(1) and C(5)C(6)C(7)O(1) are 61.4(5)° and -114.4(4)°. The thermal stability studies indicate that the title compound is stable up to 341.1 °C. The spectral, electrochemistry properties and theoretical studies show that the title compound is a good candidate for the charge-transporting materials.

Full text of DOI:10.1016/j.molstruc.2014.07.062

Journal of Molecular Structure 1076 (2014) 201–207
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Structural, spectral, electrochemistry, thermal properties
and theoretical studies on 4-[N, N-di(4-tolyl)amino] benzaldehyde
-2-chloro benzoylhydrazone
Liu Lizeng a, , Li Wei , Meng Xianfang , Liu Dongzhi , Xu Gongfeng , Bai Zhengchen
⇑
b
a
b
a
a
a
College of Science, Tianjin University of Commerce, Tianjin 300134, China
School of Chemical Engineering, Tianjin University, Tianjin 300072, China
b
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
ꢀ
4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro benzoylhydrazone were synthesized and characterized.
The photophysical, thermostability properties of the titled compound were found to be distinctively modified by benzoylhydrazone structure.
DFT calculations and experimental results were coincided on structure, energy gap and electrochemistry.
The hydrogen bonding interactions within sheets and
nonpolar solvents.
p–p interactions 3D network confirmed the title compound can be used as amorphous material in
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 May 2014
Received in revised form 23 July 2014
Accepted 23 July 2014
Available online 30 July 2014
The title compound 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro benzoylhydrazone (C28H24ClN O,
3
r
M = 453.96) was synthesized by the reaction of 4-[N, N-di(4-tolyl)amino] benzaldehyde with
1
13
2
-chlorobenzohydrazide, and its structure was characterized by IR, H NMR, H NMR, high-resolution
mass spectrometry and single-crystal X-ray diffraction. The crystal belongs to Monoclinic, space group
3
P2(1)/n with a = 12.626(3), b = 12.609(3), c = 15.837(3) Å, b = 90.00(3)°, Z = 5, V = 2512.5(9) Å ,
3
À1
r
M = 453.95, Dc = 1.280 g/cm , l = 0.183 mm , F(000) = 1024, R = 0.0432 and wR = 0.1087. X-ray analysis
Keywords:
revealed that one of the benzene ring and acylhydrazone were essentially planar, the 2-chloro benzene
ring and amide were non-planar, the torsion angles C(1)AC(6)AC(7)AO(1) and C(5)AC(6)AC(7)AO(1)
are 61.4(5)° and À114.4(4)°. The thermal stability studies indicate that the title compound is stable up
to 341.1 °C. The spectral, electrochemistry properties and theoretical studies show that the title
compound is a good candidate for the charge-transporting materials.
Triphenylamine
Crystal structure
Photophysical
Electrochemistry
Thermal property
DFT
Ó 2014 Elsevier B.V. All rights reserved.
Introduction
preparation/purification procedures, lower cost and the high
reproducibility in the performance of the device. The recent exten-
In the process of the large-scale manufacturing of the opto
devices, amorphous molecular materials used as hole-transport
materials must be capable of forming uniform amorphous thin
films by either vacuum deposition or spin coating from solution.
Triphenylamine-based hydrazones used as organic hole-transport
materials have been widely studied [1–6]. Up to now, the efforts
have been laid on developing solution processable organic
small molecules, for that they offer the advantages of simple
sive studies have revealed that small triphenylamine-based mole-
cules can also form stable amorphous glasses above room
temperature if their molecular structures are properly designed
[7–9]. The following strategies have been adopted for this purpose
[1]: (1) Molecules should possess nonplanar molecular structures;
(2) The incorporation of bulky and heavy substituents leads to
enhanced stability of the resulting amorphous glasses; (3) The
introduction of structurally rigid moieties can increase the thermal
stability. In our concept, we designed the triphenylamine-based
hydrazones which the enlarged system of conjugated
p-electrons
⇑
Corresponding author. Cell: +86 022 15620642015; fax: +86 022 83692436.
E-mail addresses: llzeng@tjcu.edu.cn (L. Lizeng), jkliwei@yahoo.cn (L. Wei),
of the target molecular would reinforce the inclination of the mol-
ecules to form glasses and would allow enhanced charge-carrier
mobilities. On the other hand, the presence of hydrazide and cholro
mxfang@tcju.edu.cn (M. Xianfang), dzliu@tju.edu.cn (L. Dongzhi), gfxu@tjcu.edu.cn
X. Gongfeng), bzhcheng@tjcu.edu.cn (B. Zhengchen).
(
http://dx.doi.org/10.1016/j.molstruc.2014.07.062
022-2860/Ó 2014 Elsevier B.V. All rights reserved.
0

2
02
L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
Scheme 1. Synthesis route of the compound III.
Fig. 1. Molecular structure of the compound III.
Table 1
Selected optimized and experimental geometries parameters of the title compound in ground state.
Bond lengths (Å)
Exp./cal.
Bond lengths (Å)
Exp./cal.
Bond lengths (Å)
Exp./cal.
Cl(1)AC(1)
O(1)AC(7)
N(1)AC(7)
N(1)AN(2)
N(1)AH(1)
N(2)AC(8)
N(3)AC(12)
N(3)AC(22)
N(3)AC(15)
1.737(3)/1.772
1.228(4)/1.220
1.354(4)/1.377
1.393(3)/1.361
0.901(10)/1.017
1.289(4)/1.287
1.406(4)/1.411
1.425(4)/1.425
1.439(4)/1.425
C(1)AC(2)
C(1)AC(6)
C(2)AC(3)
C(2)AH(2)
C(6)AC(7)
C(8)AC(9)
C(8)AH(8)
C(9)AC(10)
C(10)AC(11)
1.391(5)/1.396
1.392(5)/1.404
1.372(5)/1.392
0.9500/1.085
1.510(5)/1.516
1.448(4)/1.458
0.9500/1.100
C(10)AH(10)
C(11)AC(12)
C(15)AC(16)
C(16)AC(17)
C(16)AH(16)
C(17)AC(18)
C(18)AC(21)
C(21)AH(21A)
0.9500/1.088
1.404(4)/1.406
1.387(5)/1.403
1.387(5)/1.392
0.9500/1.086
1.391(5)/1.401
1.507(5)/1.511
0.9800/1.095
1.405(4)/1.404
1.376(4)/1.389
Angle (°)
Exp./cal.
Angle (°)
Exp./cal.
Angle (°)
Exp./cal.
C(7)AN(1)AN(2)
C(7)AN(1)AH(1)
N(2)AN(1)AH(1)
C(8)AN(2)AN(1)
C(12)AN(3)AC(22)
119.5(3)/119.2
122(2)/120.0
118(2)/119.2
113.9(3)/116.6
123.2(3)/120.4
C(12)AN(3)AC(15)
C(22)AN(3)AC(15)
C(2)AC(1)ACl(1)
C(6)AC(5)AH(5)
C(1)AC(6)AC(7)
118.2(3)/120.5
116.9(2)/119.1
118.7(3)/115.9
119.7/117.0
O(1)AC(7)AN(1)
O(1)AC(7)AC(6)
N(2)AC(8)AC(9)
N(2)AC(8)AH(8)
125.5(3)/123.4
121.6(3)/120.5
121.7(3)/122.1
119.2/121.3
122.7(3)/128.8
Torsion angle (Å)
Exp./cal.
Torsion angle (Å)
Exp./cal.
Torsion angle (Å)
Exp./cal.
C(7)AN(1)AN(2)AC(8)
Cl(1)AC(1)AC(6)AC(7)
N(2)AN(1)AC(7)AO(1)
N(2)AN(1)AC(7)AC(6)
C(1)AC(6)AC(7)AO(1)
177.9(3)/179.6
7.1(4)/8.9
2.9(5)/3.9
N(1)AN(2)AC(8)AC(9)
N(2)AC(8)AC(9)AC(10)
C(8)AC(9)AC(10)AC(11)
C(22)AN(3)AC(12)AC(13)
C(15)AN(3)AC(12)AC(13)
À178.8(3)/À179.9
À14.6(5)/À0.41
177.9(3)/179.6
16.5(5)/34.0
C(12)AN(3)AC(15)AC(20)
C(22)AN(3)AC(15)AC(20)
C(12)AN(3)AC(15)AC(16)
C(22)AN(3)AC(15)AC(16)
C(5)AC(6)AC(7)AO(1)
À130.3(3)/À135.7
64.3(4)/65.1
51.3(4)/45.6
À172.6(3)/À179.6
À114.1(3)/À115.2
61.4(5)/31.0
À147.9(3)/À145.1
À114.4(4)/À116.7
Exp./cal. = experimental/calculated.

L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
203
Table 2
UV–visible, fluorescence, electrochemical, thermogravimetric analysis measurements
for compounds I–III and the corresponding HOMO and LUMO energies and HOMO–
LUMO gaps (E ).
g
Compound
I
II
III
k
e
k
abs (nm)a
302
4.53
k
360
2.86
547
58
683
1.82
1.03
À5.77
À3.95
À5.81
À3.56
2.25
273.9
375
3.40
499
73
595
2.08
1.00
À5.74
À3.66
À5.86
À3.47
2.39
341.1
(104
M
À1
cm )b
À1
c
em (nm)
d
D
k
(nm)
l
onset (nm)e
336
f
E
E
E
E
E
E
E
T
g
(eV, opt)
3.69
0.79
À5.53
À1.84
À5.62
À1.42
4.20
234.1
i
g
ox (V, CV)
HOMO (eV, CV)h
LUMO (eV, CV)h
HOMO (eV, DFT)
i
i
LUMO (eV, DFT)
i
g
(eV, DFT))
(°C)
j
d
a
b
c
d
e
f
Absorption maximum in CH
The molar extinction coefficient at kmax in CH
Emission maximum in CH Cl solution.
The red-shift compared with I.
The bond edges in the UV–visible absorption spectra of the sample.
Obtained from UV–visible spectra: E = 1240/konset
2 2
Cl solution.
2
Cl
2
solution.
2
2
g
.
g
À3
Obtained from the cyclic voltammograms (in CH
2
Cl
2
(10 M), using n-Bu4-
À1
À1
NClO
4
as support electrolyte (10 M), scan rate: 50 mV s versus SCE).
h
Determined from the onset of the oxidation peak: EHOMO = ÀEoxe À 4.74e;
E
LUMO = EHOMO + E
g
[21,22].
i
Calculated by the DFT calculations at B3LYP/6-31(d) level.
Decomposition temperature.
Undetected.
j
k
l
Undetermined.
Fig. 2. The hydrogen-bonded monolayer network of the compound III.
structure was analyzed by X-ray diffraction and its photophysical,
electrochemistry, thermal properties were also evaluated.
groups should make it to be nonplanar molecular structures.
Furthermore, it is very important to understand the electrochemi-
cal properties of the triphenylamine-based model molecules,
which will help us to design suitable monomer and permit tuning
of the redox potentials of the molecular. In this paper, a new com-
pound containing triphenylamine and benzoic hydrazide substi-
tuted by chloro units has been synthesized (Scheme 1), its
Experiments
The melting point was determined on an X-6 binocular micro-
scope apparatus and the thermometer was uncorrected. Infra-red
spectra were obtained on a Bio-rad Fts3000 spectrometer in the
Fig. 3. Hydrogen bonding interactions within sheets and p–p interactions 3D network of the compound III.

2
04
L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
2
1
0
350
2-chlorobenzohydrazide II (0.21 g, 1.9 mmol) and acetic acid
20 L) was added. The reaction mixture was completed by stirring
Uv-vis
FL
(
l
I
II
III
300
250
200
150
100
50
0
for 24 h at room temperature (indicated by TLC). The product was
precipitated out of the solution. The solid was collected, washed
with methanol and dried to obtain the title compound III as a
yellow solid in 36% yield (the yield was not optimized). Melting
À1
point 111.8–112.5 °C; IR(KBr, cm ): 3441, 3186, 3026, 2920,
1
1
657, 1598, 1558, 1505, 1290, 816. H NMR (CDCl
3
, 400 MHz,
ppm): 8.09 (s, 1H, AN@CHA), 7.72 (t, 1H), 7.56 (d, 1H, J = 8.8 Hz),
7
6
.44–7.27 (m, 3H), 7.22 (d, 1H, J = 8.8 Hz), 7.10–7.00 (m, 6H),
13
.96–6.93 (m, 3H), 6.85 (d, 2H, J = 8.8 Hz), 2.31 (s, 6H, ACH
3
);
C
NMR (CDCl
3
, 100 MHz, ppm): 150.6, 144.9, 144.4, 133.8, 133.6,
131.7, 130.1, 130.0, 129.0, 128.6, 128.2, 127.2, 126.4, 125.6,
+
+
1
4
25.4, 20.9, 20.8; HR-ESI-MS (m/z, [M+H] ) calcd. for C28
54.1681, found 454.1682.
3
H25ON Cl
300
400
500
600
700
Wavelength (nm)
Fig. 4. UV–visible absorption spectra and fluorescence spectra of III.
Crystal data and structure determination
The colorless crystal of the title compound with dimensions of
À1
range as KBr disks. 1H and 13C NMR were
4
000–400 cm
0
.20 mm  0.18 mm  0.12 mm was selected for X-ray diffraction
measured on a Bruker AC-P500 Instrument (400 MHz) with CDCl
3
analysis. The data were collected by a Bruker Smart 1000 CCD
as the solvent and TMS as the internal standard. High-resolution
mass spectrometry (HRMS) data were recorded on VG ZAB-HS
mass spectrometer. The single-crystal structure was determined
on a Bruker SMART 1000 CCD diffractometer. Thermogravimetric
analysis (TGA) was performed on TA Q500 in a nitrogen atmo-
sphere at a heating rate of 5 °C/min. UV–visible absorption spectra
were recorded on a Perkin Lambda25 spectrophotometer. Cyclic
voltammetry (CV) was done on a CHI 7600 electrochemical work-
station with Pt plate, Pt wire, and standard calomel electrode (SCE)
as working electrode, counter electrode, and reference electrode,
respectively.
diffractometer equipped with a graphite-monochromatic Mo K
a
radiation (k = 0.71073 Å) using a scan mode at 113(2) K. In
u–x
the range of 2.06 6 h 6 25.02°, a total of 20,599 reflections were
collected with 4447 unique ones (Rint = 0.0378), of which 3800
were observed with I > 2r(I) and used in the succeeding refine-
ments. Intensity data were corrected for Lp factors and empirical
absorption. The structure was solved by direct methods and
expanded by difference Fourier techniques with SHELXS-97
program [12]. All the non-hydrogen atoms were located with
successive difference Fourier syntheses. The structure was refined
2
by full-matrix least-squares techniques on F using anisotropic
All reagents, unless otherwise specified, were obtained from
FengChuan Chemical Co. and used as received.
thermal parameters for all non-hydrogen atoms. All the hydrogen
atoms bonded to C atoms were located geometrically and treated
using a riding model, with CAH = 0.95–1.00 A and Uiso(H) = 1.2 or
1
.5 Ueq(C). The final refinement gave R = 0.0432, wR = 0.1087,
Synthesis of 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro
benzoylhydrazone (III)
2
2
2
2
2
w = 1/[s (Fo ) + (0.0677P) + 0.3002P] where P = (Fo + 2F
S = 1.080, (
c
)/3),
À3
D
q)max = 0.374, (
D
q)min = À0.475 e/A
.
Intermediate 4-[N, N-di(4-tolyl)amino] benzaldehyde I was
synthesized from N, N-di(4-tolyl) aniline according to the refer-
ence [10]. 2-chlorobenzohydrazide II was synthesized according
Results and discussion
+
to the literature [11] (ESI-MS(m/z, [M+H] ) = 171.2). The title
Structure description of the compounds
compound 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-chloro
benzoylhydrazone III was obtained as the following description.
The H NMR, 13C NMR, IR and HR MS analysis for the molecular
III are in good agreement with the title compound. In order to
unambiguously confirm the structure of the product, the single
1
4
-[N, N-di(4-tolyl)amino] benzaldehyde I (0.57 g, 1.9 mmol)
was dissolved in 8 mL ethanol at room temperature. Then
O1
C22
C6
N2
N1
N3
C12
C9
C7
C8
Cl1
C15
Fig. 5. The optimized geometries of the III calculated with DFT on the B3LYP/6-31G(d) level.

L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
205
with the N(1)AN(2)AC(8)AC(9) torsion angle of À178.8(3)°. The
torsion angles of N(2)AN(1)AC(7)AO(1), N(2)AN(1)AC(7)AC(6)
and O(1)AC(7)AC(6)AC(1) is 3.1(3)°, À173.54(14)°, 60.9(2)°,
respectively, which suggests that the nitrogen atom N(1) is not
placed at the same plane with the phenyl ring substituted by
chlorine atom and the plane of hydrazone structure. The dihedral
angle between the AC@N moiety and the plane of carbonyl
group (O(1)AC(7)AN(1)) is 125.23(15)°. The torsion angles of
C(5)AC(6)AC(7)AO(1) is À115.08(19)°, so the carbonyl group is
not placed at the same plane with the phenyl ring substituted by
-
-
-
5
5
5
6
4
2
.0x10
.0x10
.0x10
0
.0
-
-
-
-
5
-
-
-
-
2.0x10
4.0x10
6.0x10
8.0x10
5
5
5
chlorine atom. No direct p–p interactions are observed among all
moieties in the unit cell. Therefore, the cross-link part of target
compound is non-planar. It can be seen from Table 2 that all the
bond lengths of CAC are located between the normal C@double
bond (1.34 Å) and CAC single bond (1.54 Å), which show that III
1
.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Potential (V)
has a highly delocalized p-electron system in the molecule.
N(1)AC(7) (1.3470(2) Å) and N(2)AN(1) (1.3883(18) Å) bonds are
slightly shorter than the typical CAC bond (1.54 Å) [13] and CAN
bond (1.47 Å) [14], the typical NAN bond (1.44 Å) and N@N bond
(
A)
-
-
-
-
5
5
5
5
8
6
4
2
.0x10
.0x10
.0x10
.0x10
(
1.24 Å) [15], respectively, suggesting the NAC and NAN bonds
have partial double bond character.
The packing of III in methanol is shown in Figs. 2 and 3. The
interaction between the methanol molecule and III is reinforced
by the formation of the hydrogen bond N(1)AHÁ Á ÁO(2) and
O(2)AHÁ Á ÁO(1). The titled molecules form strong hydrogen bond
interactions with the methanol molecules forming infinite 1D
chains. These chains are inter-linked via NAHÁ Á ÁO and OAHÁ Á ÁO
interactions involving carbonyl groups/amide groups to form 2D
independent sheets cross-linked via one methanol molecule
0
.0
-
-
-
-
-
5
-
-
-
-
-
2.0x10
4.0x10
6.0x10
8.0x10
1.0x10
5
5
5
4
(Fig. 2). In Fig. 3, there are some intermolecular weak p–p interac-
tions between the two III species, with the separation between the
two benzene planes titled as C9AC10AC11AC12AC13AC14 being
3.7790 Å (center to center), 3.4571 Å (center to plane), respec-
tively. The p-interactions are hence crucial for the crystal packing
stabilization. These weak interactions are largely responsible for
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Potential (V)
(
B)
the thermodynamic stability of the crystal system.
-
5
Photophysical properties of III
6
.0x10
.0x10
.0x10
-
5
The UV–visible absorption spectra and fluorescence spectra of
4
À5
compound I–III (4 Â 10 M in CH
2 2
Cl ) are shown in Fig. 4. Broad
absorption bands covering the wavelength range from 250 to
50 nm can be observed for all compounds, the kmax exhibits
-
5
2
4
red-shifted by roughly 73 nm when going from I to III. This trend
is in agreement with the trend previously reported in the case of
homologous series of conjugated triphenylamine-core hydrazones
0
.0
-
-
-
5
-
-
-
2.0x10
4.0x10
6.0x10
[
16]. This red-shift can be related to the geometrical changes that
occur in the longest conjugated chain length composed by the
planarization of C(8)AC(9)AN(1)AN(2)AC(7)AO(1) when compar-
ing the geometries to the structure of I which, consequently,
5
5
improves the
p-conjugation and decreases the HOMO–LUMO gaps.
Compound III has two absorption peaks (kmax) at 296 and 375 nm
2
1
0
-1
-2
*
which can be assigned to the
17–19], which is similar to that of II. Also, the molar extinction
coefficients in dilute CH Cl solution was calculated as
.40 Â 10 M cm (kmax = 375 nm) for III. The optical band gaps
(E ) are calculated as 2.08 eV for III. The fluorescence spectra of the
p–p absorption of the molecule
Potential (V)
[
(
C)
2
2
4
À1
À1
3
Fig. 6. Multiple cyclic voltammograms scans of I(A), II(B), III(C) (cycle 1st to 10th).
g
title compound shows a emission peak wavelength at 499 nm
excited by 380 nm. The maximum emission bonds of I–III in fluo-
rescence spectra exhibit the trend of II > III (compound I was not
excited by 380 nm), and III show a stronger intensity when the
length of the conjugated system is increased, exhibiting emission
maxima ranging from 547 nm for II to 499 nm for III. The molecule
III exhibits a broad absorption range and a relatively low band gap,
which would be in favor of light-harvesting when used as the
active-layer material in optical devices.
crystal of III was analyzed by X-ray diffraction apparatus. The
molecular structure is shown in Fig. 1. The selected bond lengths
and bond angles are listed in Tables 1 and 2.
The geometry of the N(3) atom is a distorted tetrahedral config-
uration with the C(12)AN(3)AC(22), C(12)AN(3)AC(15) and C(22)
AN(3)AC(15) angles of 123.2(13)°, 118.23(13)° and 116.79(12)°.
The configuration of
p cross section (AC@N) is basically a plane

2
06
L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
(
A)
0
-
1
2
3
4
5
6
7
-
-
-
-
-
-
(
B)
Fig. 7. HOMO and LUMO pictograms for compounds I–III (A); comparison of the electrochemical and theoretical (B3LYP/6-31G(d) level) HOMO and LUMO energies of
compounds I–III(B).
Electronic structure and electrochemical properties
and the theoretical calculations. Compared with the experimental
data for the title compound, it is well known that DFT optimized
bond lengths, bond angles and dihedral angles show the stron-
gest correlation with the experimental values (Table 1). Although
the largest difference between experimental and calculated tor-
sion angle is about 61.4(5)°/31.0° for C(1)AC(6)AC(7)AO(1),
À14.6(5)°/À0.41° for N(2)AC(8)AC(9)AC(10), the same trend
was coincided between the real structure and DFT optimized struc-
ture. According to those results, the optimized geometry is
obtained for molecule III coincides with the crystalline structure
of III.
To gain insight into the geometrical properties and scrutinize
the charge transfer on excitation, the ground-state geometries of
the III had been optimized in the gas phase by DFT with the
Gaussian03 package, using the hybrid B3LYP functional and the
standard 6-31G(d) basis set before the beginning of experimental
synthesis of III (Fig. 5). The optimized parameters (bond lengths,
bond angles and dihedral angles) of the title compound were
listed in Table 1. A global comparison was performed by super-
imposing the molecular skeletons obtained from X-ray diffraction

L. Lizeng et al. / Journal of Molecular Structure 1076 (2014) 201–207
207
2
73.9 °C for II), the TGA results of III show that the model com-
1
00
I
II
III
pound has enough resistance against thermal decomposition,
which is due to the presence of the acylhydrazone structure in
the compound III.
8
6
4
2
0
0
0
0
0
Conclusions
A novel compound 4-[N, N-di(4-tolyl)amino] benzaldehyde-2-
chloro benzoylhydrazone was synthesized and characterized by
1
13
IR, HRMS, H NMR and C NMR. The single crystal was cultivated
and analyzed by single-crystal X-ray diffraction. In the crystal
structure, the chloro substituted benzoylhydrazone moiety leads
to the non-planar structure formation and modified the photo-
physical, and thermal properties of the titled compound. The ther-
mal and electrochemistry stability of the title compound has been
studied, and the most weight was lost when the temperature is at
-
20
100
200
300
400
500
)
600
700
800
Temperature (
Fig. 8. TGA of the compound III.
3
41.1 °C. The titled compound as charge-transfer materials and
ligand precursors for the generation of new metal complexes
would extend these materials promising for optical devices. The
packing structure of III in methanol show that the compound III
used as amorphous material should avoid to be dissolved in alco-
hol or polar solvents. As it was already mentioned in the compar-
ison between the experimental and theoretical study, the DFT
calculations was used to assist designing some triphenylamine-
based derivatives was in progress.
Due to the energy levels in the organic semiconductors are of
great importance, density functional theory (DFT, B3LYP/6-31(d)
level) methods and cyclic voltammetry was performed to investi-
gate the electrochemical properties and HOMO (highest occupied
molecular orbital) and LUMO (lowest unoccupied molecular
orbital) energy levels of compounds I–III. The HOMO energy levels
with respect to the vacuum level correspond to the oxidation
potential (Eox). Based on the optimized geometry at the B3LYP/
Acknowledgements
6
-31G(d) level, we have designed, synthesized, investigated and
calculated triphenylamine-based organic charge transferring
materials. The experimental data and calculation of the EHOMO
LUMO and E were shown schematically in Figs. 6 and 7 and
This work was supported by Tianjin University of Commerce
Students’ Innovation Project, the Innovation Fund for Small
Technology-Based Firms of Tianjin (No. 13zxcxgx01052) and the
National Natural Science Foundation of China (No. 31271935).
,
E
g
Table 2. Our calculations of I–III reveal the HOMO electron density
mainly localized on the TPA core and the LUMO electron density
mainly localized on the conjugated moiety to the TPA core in II
and III. Compared with that of I, adding AC@OA and AC@N conju-
gated structure to the TPA core in II/III makes the HOMO(LUMO)
energies increase (decrease) resulting in decreasing HOMO–LUMO
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3
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d
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