A blue-emitting organic compound 9-hydroxyl-3-hydroxyethyl-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one: Synthesis, crystal structure and luminescent properties

Article abstract of DOI:10.1016/j.saa.2010.02.036

A blue-emitting organic compound, 9-hydroxyl-3-hydroxyethyl-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (I), was synthesized by the reaction of 2-amino-3-hydroxylpridine with 2-acetylbutyrolactone. The crystal of the title compound in larger size was reported for the first time through the slow evaporation method. The whole molecule in the crystal is non-planar, but the two conjugated rings are almost co-planar (with an average dihedral angle of only about 1.621°). The hydroxyl group is in trans position to the pyrido[1,2-a]pyrimidin heterocyclic moiety. The molecules are linked by the N-H?O, O-H?O and C-H?O hydrogen bonds into two-dimensional sheets. Additionally, the π-π interactions (average distance 3.3680 A?) interconnect the sheets stabilizing the crystal structure. At room temperature, the compound exhibits an intense blue emission at 432 nm upon 323 nm excitation in the solid state. The simple EL device with the configuration of ITO/I + PMMA/Ag was fabricated, where the compound (I) was used as a main emitting material. The EL device fabricated had a maximum brightness of 289 cd m^-2. The thermal stability of the compound was also investigated by thermogravimetric analysis (TGA).

Full text of DOI:10.1016/j.saa.2010.02.036

Spectrochimica Acta Part A 76 (2010) 464–469
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
A blue-emitting organic compound
9-hydroxyl-3-hydroxyethyl-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one:
Synthesis, crystal structure and luminescent properties
Huaihong Zhanga,b, Yu Suna, Xiaodan Chena, Chao Lia, Baiwang Suna,∗
a College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
b Department of Chemistry and Biology, Yancheng Institute of Technology, Yancheng 224003, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A blue-emitting organic compound, 9-hydroxyl-3-hydroxyethyl-2-methyl-4H-pyrido[1,2-a]pyrimidin-
4-one (I), was synthesized by the reaction of 2-amino-3-hydroxylpridine with 2-acetylbutyrolactone. The
crystal of the title compound in larger size was reported for the first time through the slow evaporation
method. The whole molecule in the crystal is non-planar, but the two conjugated rings are almost co-
planar (with an average dihedral angle of only about 1.621◦). The hydroxyl group is in trans position
to the pyrido[1,2-a]pyrimidin heterocyclic moiety. The molecules are linked by the N–H· · ·O, O–H· · ·O
and C–H· · ·O hydrogen bonds into two-dimensional sheets. Additionally, the ␲–␲ interactions (average
distance 3.3680 Å) interconnect the sheets stabilizing the crystal structure. At room temperature, the
compound exhibits an intense blue emission at 432 nm upon 323 nm excitation in the solid state. The
simple EL device with the configuration of ITO/I + PMMA/Ag was fabricated, where the compound (I) was
used as a main emitting material. The EL device fabricated had a maximum brightness of 289 cd m−2. The
thermal stability of the compound was also investigated by thermogravimetric analysis (TGA).
© 2010 Elsevier B.V. All rights reserved.
Received 24 November 2009
Received in revised form 21 February 2010
Accepted 26 February 2010
Keywords:
Crystal structure
X-ray diffraction
Hydrogen bond
Blue-emitting
1. Introduction
and photochemical stabilities and excellent fluorescence proper-
ties [12–15]. A number of 8-hydroxyquinoline derivatives have
An ongoing interest over the past two decades has been
expressed in developing all-organic light-emitting devices as alter-
natives to inorganic based systems. Organic small molecules [1–3]
and light-emitting polymers [4,5] have potential advantages not
only in lower synthetic costs, but most importantly, organic light-
emitting device (OLED) materials have been shown to be amenable
to large scale-up, high efficiencies, simple and inexpensive fabri-
cation routes to achieve the device [6–8]. Because blue-emitting
materials should have a large enough energy gap and many blue-
emitting materials reported actually emitted blue-green light in
their devices, which was induced by their wide emission ranges,
bright and stable blue-emitting materials with high color purity are
limited. Several efficient UV molecular host materials integrated
with suitable blue-emitting dopants have been developed [9].
Recently, many researchers have tried to come up with ultimate,
nondoped hosts by utilizing the derivatives of bistriphenylenyl
[10] and diarylfluorene/spirobifluorene [11]. The heterocyclic
molecules have received much attention for their strong electron-
withdrawing capabilities, comparatively better chemical, thermal
been synthesized for the purpose of color tuning and better device
performance. In all cases the emission of 8-hydroxyquinoline
derivatives has been attributed to the ␲–␲* transitions in 8-
hydroxyquinoline ligand. The highest occupied molecular orbital
(HOMO) is mostly located on phenoxide ring while lowest unoccu-
pied molecular orbital (LUMO) on pyridyl ring [16].
At present report, we describe the synthesis, molecular struc-
ture and luminescent property of the 9-hydroxyl-3-hydroxyethyl-
2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one. The thermal stability
of the title compound was also evaluated.
2. Experimental procedure
2.1. Physical measurements
Elemental analyses (C, H and N) were carried out on a Perkin-
Elmer 240C analytical instrument. IR spectra were recorded on
a Nicolet 170SX FT-IR spectrophotometer with KBr pellets in the
4000–400 cm−1 region. Fluorescent spectra were measured on an
Edinburgh Instruments analyzer model FL920. The TGA was car-
ried out on a Shimadzu thermogravimetric analyzer in dry nitrogen
atmosphere and heating rate of 10 ◦C/min using the TA-50 WS1
program.
∗
Corresponding author. Tel.: +86 25 52090614.
E-mail address: chmsunbw@seu.edu.cn (B. Sun).
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.02.036

H. Zhang et al. / Spectrochimica Acta Part A 76 (2010) 464–469
465
Scheme 1.
2.2. Materials
propanol. The title compound crystals were grown from saturated
2-propanol solution at 30 ◦C by slow evaporation technique.
The starting materials were purchased commercially and used
without further purification.
2.4. Single crystal X-ray diffraction
Suitable crystal of title compound was selected and subjected
to single crystal X-ray structure solution studies. Intensity data
were collected at 293(2) K on a Siemens SMART-CCD diffractome-
ter with graphite monochromatic MoKa radiation (ꢀ = 0.7107 Å).
Data reductions and absorption corrections were performed with
the SAINT and SADABS software packages, respectively. The struc-
tures were solved by direct methods using SHELXS-97 and were
refined by full-matrix least-squares methods using SHELXL-97 [17].
Anisotropic displacement parameters were refined for all non-
hydrogen atoms except for the disordered atoms. The hydrogen
atoms except for those of water molecules were generated geo-
metrically and refined using a riding model. The crystallographic
data and structure refinement of (I) are stacked in Table 1.
2.3. Synthesis and crystal growth
The synthesis route of the title compound was expressed
in Scheme 1.
A suspension of 2-amino-3-hydroxypyridine
(4.4 g, 0.04 mol), 2-acetylbutyrolactone (6.5 g, 0.05 mol), p-
toluenesulfonic acid monohydrate (0.23 g, 1.2 mmol) in 50 ml
chlorobenzene was heated to reflux for 20 h. The reaction solution
was allowed to cool slowly to room temperature. The light yellow
solid was collected by filtration and dried in vacuum. Yield: 0.51 g,
84%. 1H NMR (DMSO-d6, ppm): 10.46 (1H, phenolic), 8.63–8.71 (2H,
aromatic), 7.20–7.36 (1H, aromatic), 4.72 (1H, –CH2OH), 2.19(2H,
–CH2), 2.89(3H, –CH3), 3.52 (2H, –CH2OH). Element analysis Calcd.
(%) for C11H12N2O3: C 60.02, H 5.47, N 12.73; Found: C 60.01, H
5.49, N 12.81. IR (KBr, cm−1); 3530 (–OH stretching); 3055 (C–H
stretching, aromatic); 2984 (C–H stretching of methyl); 1735 (C
O
2.5. Fabrication of organic electroluminescent (EL) devices
(OLEDs)
stretching); 1605 (C N stretching); 1510, 1472 (C C stretching,
aromatic); 1278 (O–H deformation). MS (m/e): 219.1[M+].
The solution growth technique is widely employed to grow sin-
gle crystals of organic compounds. In order to select the suitable
solvent for crystal growth, the solubility of title organic com-
pound, in different solvents such as methanol, ethanol, 2-propanol,
acetonitrile, chlorobenzene and ethyl acetate was measured. The
solubility of title compound in different solvents was assessed as
a function of temperature in the range 25–60 ◦C. The saturated
solution was allowed to reach the equilibrium in about 24 h at a
chosen temperature, and then the solubility was gravimetrically
analyzed. The same process was repeated for different tempera-
tures, and the solubility curve was obtained. The typical solubility
curves of the title organic compound in 2-propanol, acetonitrile
and chlorobenzene are shown in Fig. 1. The title compound exhibits
good solubility and a positive solubility–temperature gradient in 2-
The simple EL device with the structure of ITO/I + PMMA/Ag was
fabricated under clean-room conditions in a nitrogen atmosphere
inside a glove box ([O2], [H2O] < 1 ppm) by using indium tin oxide
(ITO)-coated glass substrates (sheet resistance = 30 ꢁ/sq) that were
first cleaned with detergents and deionized water, dried in an oven
at 120 ◦C for 4 h and then treated in an UV-ozone reactor. The elec-
troluminescent layer consisted of I as the main component, mixed
with 25% (w/w) poly(methyl methacrylate) (PMMA) to improve
film formation and stability [18]. The layer was spin-coated at
Table 1
Crystal data and structure refinement for (I).
Empirical formula
C11H12N2O3
Formula weight
220.23
Temperature
298(2) K
Wavelength
0.71073 Å
Crystal system, space group
Unit cell dimensions
Monoclinic, P21/n
a = 11.1111(11) Å, ˛ = 90.00◦,
b = 6.8032(7) Å, ˇ = 96.0720(10)◦,
c = 13.3625(15) Å, ꢂ = 90.00◦
1004.42(18) Å3
Volume
Z, calculated density
Absorption coefficient
F(0 0 0)
4, 1.456 Mg/m3
0.108 mm−1
464
Crystal size
Theta range for data collection
Limiting indices
0.4 mm × 0.3 mm × 0.27 mm
2.27–25.01◦
−8 < h < 13, −8 < k < 7, −15 < l < 15
4710/1724[R(int) = 0.0436]
25.01, 97.8%
0.9715 and 0.9582
Full-matrix least-squares on F2
1724/0/145
Reflections collected/unique
Completeness to theta
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2∧
Final R indices [I > 2sigma(I)]
R indices (all data)
1.047
R1 = 0.0934, wR2 = 0.2612
R1 = 0.1224, wR2 = 0.2870
0.720 and −0.353e Å−3
Largest diff. peak and hole
Fig. 1. Solubility of (I) in different solvents.

466
H. Zhang et al. / Spectrochimica Acta Part A 76 (2010) 464–469
Table 2
FT-IR spectral data of (I).
Frequencies (cm−1
)
Assignments
3530
3490
3055
2984
Phenolic O–H stretching
Aliphatic O–H stretching
Aromatic C–H stretching
Aliphatic C–H stretching
1735
1605
C
C
O stretching
N stretching
1510, 1472
1402, 1321
768
Aromatic C C stretching
C–N–C stretching
Aromatic C–H out of plane bending
C–N wagging
695
Table 3
Selected torsion angles [◦] for (I).
Fig. 2. A view of (I) molecule showing displacement ellipsoids at the 50% probability
O(3)–C(9)–C(10)–C(2)
C(3)–C(2)–C(10)–C(9)
C(1)–C(2)–C(10)–C(9)
−173.1(3)
−93.2(5)
86.3(5)
level and H atoms as a sphere of arbitrary radii.
5000 rpm from DMSO solution on the ITO-coated glass substrates
and volatilizing the solvent in a vacuum oven yielding a final thick-
ness of about 250 nm. Prior to spin-coating the solutions were dried
with molecular sieves and filtered. Ag, as the top electrode, was
applied by vacuum evaporation through a mask at an evaporation
rate of 5 Å s−1 to yield a final thickness of 100 nm. The emission
area of the devices was 15 mm2 as determined by the overlap
area of the anode and the cathode. The EL spectra were measured
using a PR650 spectra colorimeter. The current–density–voltage
and brightness-voltage curves of the devices were measured using
a Keithley 2400 source meter and a calibrated silicon photodiode.
All the experiments and measurements were carried out at room
temperature under ambient conditions.
Table 4
Selected bond lengths (Å) in (I).
N(1)–C(8)
N(1)–C(4)
N(1)–C(1)
N(2)–C(4)
N(2)–C(3)
O(1)–C(1)
O(2)–C(5)
1.374(6)
1.383(6)
1.440(5)
1.330(6)
1.352(5)
1.246(5)
1.338(5)
3.2. Crystal structure of the title compound
The asymmetric unit of the crystal is illustrated in Fig. 2,
the two conjugated rings are almost co-planar with an dihedral
angle of only about 1.621(130)◦. The values of torsion angles
around the bonds C10–C9 and C10–C2, where free rotation can
occur, determine the molecule’s shape (Table 3). Fig. 2 shows the
hydroxyethyl group is out of the pyrido[1,2-a]pyrimidine plane,
where the hydroxyl group is in trans position to the pyrido[1,2-
a]pyrimidine heterocyclic moiety. The C–N bond lengths of the
pyrido[1,2-a]pyrimidine heterocyclic moiety are in the range of
1.330(6)–1.440(5) Å. The N(2)–C(4) bonds are shorter than the
remaining four C–N bonds within pyrido[1,2-a]pyrimidine het-
erocyclic moiety (Table 4). This can be ascribed to the double
N(2)–C(4) bond. The O(1)–C(1) bond with a distance of 1.246(5) Å
is shorter than the O(2)–C(5) bond (1.338(5) Å) and O(3)–C(9) bond
(1.422(6) Å) (Table 4), which is due to the double O(1)–C(1) bond
(Fig. 3).
3. Results and discussion
3.1. Infrared spectra
The FT-IR analysis of (I) was carried out to investigate the pres-
ence of functional group and their vibrational modes, which is
summarized in Table 2. The importance of hydrogen bonding in the
packing of (I) molecules in the crystal lattice is greatly evident by
the broadened envelope due to phenolic stretch around 3530 cm−1
.
The aromatic C–H stretching shows a signal at 3055 cm−1. The
bands at 2916 and 2525 cm−1 are due to the O–H stretching of
the hydroxyethyl group involved in intramolecular hydrogen bond-
ing. The presence of C O stretching is indicated by the peak at
1735 cm−1. The C C stretching vibrations of the aromatic ring
skeleton are observed by the two bands at 1510 and 1472 cm−1
.
The intense peak at C–N stretch is observed at 1402 cm−1. From
this spectroscopic investigation, the grown crystal was deciphered
qualitatively to be the title compound.
There are significant intermolecular hydrogen bond inter-
actions in the solid state of title compound (I) involving the
O–H· · ·O (O2–O1 = 2.599(4) Å, O3–O2 = 3.025(5) Å) and O–H· · ·N
Fig. 3. A view of the 1D chain in the compound along b-axis. All do not take part in H-bond H atoms are omitted for clarity.

H. Zhang et al. / Spectrochimica Acta Part A 76 (2010) 464–469
467
Fig. 4. A view of the 2D chain in the compound along b-axis. All do not take part in H-bond H atoms are omitted for clarity.
tion maximum at 338 nm (Fig. 6). The absorption bands in the
250–380 nm range can be assigned to intramolecule (␲–␲*) tran-
sitions. Upon irradiation by UV-light at room temperature, the
compound solution shows a deep blue emission with a peak at
403 nm. In the solid state, the compound shows broad emission
bands at 432 nm, which is red-shifted from the solution emission
(O3–N2 = 3.085(6) Å), which makes the whole compound form-
ing one-dimensional chains. Two neighbouring chains interact via
the weak C–H· · ·O hydrogen bonds (C7–O3 distance 3.286(6) Å,
ꢀCHO = 156.329(282)◦) connecting the C7H7 moiety of one
molecule to the O3 of the neighbouring one into two-dimension
sheets (Fig. 4). Furthermore, the 2D sheets are extended into
a 3D supramolecular framework via the face-to-face stacking
interactions between conjugated rings of pyrido[1,2-a]pyrimidine
heterocyclic moiety (Fig. 5). All hydrogen bond parameters are
listed in Table 5.
Table 5
Hydrogen bonds for (I) [Å and◦].
D–H· · ·A
d(D–H)
d(H· · ·A)
d(D· · ·A)
<DHA
O2–H2· · ·O1a
O3–H3· · ·N2b
O3–H3· · ·O2b
0.820
0.820
0.820
1.820
2.376
2.434
2.599
3.085
3.026
158.15
145.07
129.87
3.3. Optical property of the compound
a
3.3.1. UV–vis absorption and fluorescence emission spectrum
The luminescent properties including absorption and fluores-
cent characteristics of (I) in ethanol solution (2 × 10−5 mol/L)
have been studied. The solution of compound exhibits an absorp-
x + 1/2, −y + 1/2, z + 1/2.
x − 1/2, y + 1/2, z − 1/2.
b
Fig. 6. UV–vis absorption of (I) in ethanol at room temperature. Insert: The emission
spectra of the compound in the solid state (red line) and in ethanol (blue line) with
excitation at 323 nm and 283 nm at room temperature. (For interpretation of the
references to color in this figure caption, the reader is referred to the web version
of the article.)
Fig. 5. View of the crystal packing of (I). Dashed lines represent the N–H· · ·O,
O–H· · ·O and C–H· · ·O hydrogen bonding that stabilize the 3D structure.

468
H. Zhang et al. / Spectrochimica Acta Part A 76 (2010) 464–469
Fig. 9. EL at different values of voltages for the device.
Fig. 7. Fluorescence spectra of (I) in ethanol solution with different concentrations.
around 400 nm. However, the PL emission behavior of (I) in DMF is
significantly different from that in DMSO or ethanol. In DMF, the flu-
orescence spectrum of (I) shows emission maxima around 435 nm
and displays a quite change as a function of the solvent polarity.
Meanwhile, the emission intensity of (I) is varying with the sur-
rounding medium. The greatest emission intensity in ethanol is
observed, while there is least emission intensity in DMSO. This may
be attributed to charge transfer between compound and solvent in
excited states. Further research toward a better understanding of
this action is currently in progress.
spectra. As revealed by the crystal packing diagram of (I), the aro-
matic ␲–␲ interactions of the pyrido[1,2-a]pymidine moieties in
the solid state should be responsible for the observed low-energy
solid-state emissions.
3.3.2. Effects of concentration on photoluminescence
The fluorescence spectra of (I) in ethanol solution at different
concentrations were measured and shown in Fig. 7. It can be seen
that the concentration of (I) in low concentration 1.0 × 10−5 mol/L,
the maximal fluorescence emission is at 403 nm, which exhibits
only one emission band and its spectrum as ‘a’ shown. On pro-
gressive increase in concentration of compound, the fluorescence
intensity of compound decreases obviously, which is ascribed to
quench efficiently.
3.3.4. Electroluminescence characteristics
To study the electroluminescence characteristics, a regulated
voltage supply with current limitation was connected to the ITO
(positive) and silver (negative) electrodes and the voltage was
raised until electroluminescent appeared. The color emitted by the
fabricated device was blue with an EL peak at 453 nm (Fig. 9), which
indicates clearly that the emission at 453 nm is from the title com-
pound used as light-emitting material in OLEDs fabrication. Though
EL and PL spectra exhibited similar emitting patterns, the EL maxi-
mum peak position shifted about 21 nm with respect to its PL peak
at 432 nm in solid state. The results also showed that some interac-
tion occurs at the interface between the title organic compound (I)
and the PMMA in the EL device structure. The electroluminescence
(EL) intensity of the device increased with increase in voltage from
8 V to 14 V as shown in Fig. 9.
3.3.3. Effects of solvent on photoluminescence
The investigation on the interaction between the compound
molecules and the solvents was helpful to understand the optical
property of the compound and apply it to small molecule organic
light-emitting diodes (SMOLEDs). The interaction between them in
diluted solutions is examined by fluorescence spectrophotometry.
The emission spectra of (I) in different solvents with the same con-
centration (2.0 × 10−5 mol/L), including ethanol, DMF and DMSO
and the results are shown in Fig. 8. It can be seen from Fig. 8
that the compound exhibited a very similar PL emission behav-
ior in DMSO and ethanol and the dominant signal is observed
The representative luminance–voltage curve and the current
intensity–voltage curve of device containing the synthesized title
Fig. 8. The emission spectra of (I) in different solvents.
Fig. 10. Current–voltage curve and luminance–voltage curve of the EL device.

H. Zhang et al. / Spectrochimica Acta Part A 76 (2010) 464–469
469
organic material exhibits a deep blue emission at 432 nm upon
323 nm excitation in solid state. The compound (I) was employed
as an emitting component in fabricating OLEDs that had emission
peak at 453 nm with a maximum brightness of 289 cd m−2. The
compound (I) is stable up to 190 ◦C. The performance of the fabri-
cated device was not very good at brightness but it is supposed to
improve by some optimizations in the device parameters, which
will be our further investigation.
Supplementary material
The crystallographic data have been deposited at the Cambridge
Crystallographic Data Center (CCDC 740893). Copies of this infor-
mation may be obtained free of charge from: CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (Fax: +44 1223 336033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
Fig. 11. TGA/DTA curve of (I) crystal.
Acknowledgements
organic compound are shown in Fig. 10. The turn-on voltage of the
device was 9 V, where turn-on voltage was taken as the voltage
required in achieving the luminance of 1 cd m−2. Current intensity
and the luminance increased with the increase of bias voltage. The
blue light emitted from the EL device had a maximum brightness
of 289 cd m−2 at 16 V.
The present work was supported by the National Natural Sci-
ence Foundation of China (No. 20671019). The authors thank the
Order Material Central of Southeast University for supporting this
work.
References
3.4. Thermal properties of the compound crystal
[1] L.S. Huang, C.H. Chen, Mater. Sci. Eng. R 39 (2002) 143–222.
[2] C.T. Chen, Chem. Mater. 16 (2004) 4389–4400.
Fig. 11 shows the thermal properties of (I) crystal carried out by
TGA and DTA. The DTA curve of (I) shows an endothermic peak at
151.4 ◦C, which can be attributed to the melting point of the sample.
The (I) melting point of 151 ◦C is confirmed by direct observation
using MONOTECH melting apparatus. There is a gradual weight loss
from 151 to 170 ◦C due to evaporation. The steep weight loss around
190 ◦C is due to the boiling of the melt. The boiling of the melt is
confirmed by direct observation. The final residue weight left was
about 4% after heating beyond 210 ◦C.
[3] Y. Wei, C.T. Chen, J. Am. Chem. Soc. 129 (2007) 7478–7479.
[4] J.H. Burroughes, D.D.C. Bradley, A.R. Brown, R.N. Marks, K. Mackay, R.H. Friend,
P.L. Burns, A.B. Holmes, Nature 347 (1990) 539–541.
[5] R. Pudzich, T. Fuhrmann-Lieker, J. Salbeck, Adv. Polym. Sci. 199 (2006) 83–
142.
[6] U. Mitschke, P. Bauerle, J. Mater. Chem. 10 (2000) 1471–1507.
[7] L. Akcelrud, Prog. Polym. Sci. 28 (2003) 875–962.
[8] A. Misra, P. Kumar, M.N. Kamalasanan, S. Chandra, Semiconductor Sci. Technol.
21 (2006) R35–R47.
[9] J.R. Gong, L.J. Wan, S.B. Lei, C.L. Bai, X.H. Zhang, S.T. Lee, J. Phys. Chem. B 109
(2005) 1675–1682.
[10] H.T. Shih, C.H. Lin, H.H. Shih, C.H. Cheng, Adv. Mater. 14 (2002) 1409–1412.
[11] S. Tao, Z. Peng, X. Zhang, P. Wang, C.S. Lee, S.T. Lee, Adv. Funct. Mater. 15 (2005)
1716–1721.
4. Conclusion
[12] G.S. He, J. Swiatkiewicz, Y. Jiang, P.N. Prasad, B.A. Reinhardt, L.S. Tan, R. Kannan,
J. Phys. Chem. A 104 (2000) 4805–4810.
The
9-hydroxyl-3-hydroxyethyl-2-methyl-4H-pyrido[1,2-
[13] R. Kannan, G.S. He, L. Yuan, F. Xu, P.N. Prasad, A.G. Dombroskie, B.A. Reinhardt,
J.W. Baur, R.A. Vaia, L.S. Tan, Chem. Mater. 13 (2001) 1896–1904.
[14] K.D. Belfield, A.R. Morales, B.S. Kang, J.M. Hales, D.J. Hagan, E.W.V. Stryland,
V.M. Chapela, J. Percino, Chem. Mater. 16 (2004) 4634–4641.
[15] P. Shao, B. Huang, L. Chen, Z. Liu, J. Qin, H. Gong, S. Ding, Q. Wang, J. Mater.
Chem. (2005) 4502–4506.
[16] A. Curioni, W. Andreoni, IBM J. Res. Dev. 45 (2001) 101–114.
[17] G.M. Sheldrick, Acta Crystallogr. Sect. A: Found. Crystallogr. 64 (2008) 112–122.
[18] H. Rudmann, M.F. Rubner, J. Appl. Phys. 90 (2001) 4338–4345.
a]pyrimidin-4-one was synthesized and its single crystals
structure was confirmed by X-ray diffraction analysis. X-ray
investigations show that the aromatic rings of (I), which adopt
a trans configuration about the hydroxyethyl group are nearly
co-planar. A significant intermolecular interaction is noted, involv-
ing O–H· · ·O, O–H· · ·N, C–H· · ·O and ␲–␲ stacking, such that a
three-dimensional feature is formed. At room temperature, the