New luminescent 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile: Synthesis, crystal structure, DFT and photophysical studies

Article abstract of DOI:10.1016/j.saa.2014.01.006

In the current communication, we report the synthesis, spectroscopic, crystal structure, DFT and photophysical studies of a new nicotinonitrile derivative, viz. 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile (2) as a potential blue light emitting material. The compound 2 was synthesized in good yield via a simple route. The acquired spectral and elemental analysis data were in consistent with the chemical structure of 2. The single crystal study further confirms its three dimensional structure, molecular shape, and nature of short contacts. Its DFT calculations reveal that compound 2 possesses a non-planar structure and its theoretical IR spectral data are found to be in accordance with experimental values. In addition, its UV-visible and fluorescence spectral measurements prove that the compound exhibits good absorption and fluorescence properties. Also, it shows positive solvatochromic effect when the solvent polarity was varied from non-polar to polar.

Full text of DOI:10.1016/j.saa.2014.01.006

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
New luminescent 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotino-
nitrile: Synthesis, crystal structure, DFT and photophysical studies
T.N. Ahipa a, Pooja R. Kamath a, Vijith Kumar b, Airody Vasudeva Adhikari a,
⇑
a Department of Chemistry, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025, India
b Solid State Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
ꢀ
A new D–A type 2-methoxy-6-(4-
methoxy-phenyl)-4-p-tolyl-
nicotinonitrile (2) compounds was
designed and synthesized.
ꢀ
ꢀ
ꢀ
ꢀ
Its crystal structure analysis confirms
the presence of non-conventional
intermolecular H-bonds.
It exhibits positive solvatochromic
behaviour with the variation of
solvent systems.
The photophysical studies reveal that
the compound is good blue emissive
material.
DFT calculations were performed to
obtain optimized geometry and
theoretical IR stretching vibrations.
a r t i c l e i n f o
a b s t r a c t
Article history:
In the current communication, we report the synthesis, spectroscopic, crystal structure, DFT and photo-
physical studies of a new nicotinonitrile derivative, viz. 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nic-
otinonitrile (2) as a potential blue light emitting material. The compound 2 was synthesized in good yield
via a simple route. The acquired spectral and elemental analysis data were in consistent with the chem-
ical structure of 2. The single crystal study further confirms its three dimensional structure, molecular
shape, and nature of short contacts. Its DFT calculations reveal that compound 2 possesses a non-planar
structure and its theoretical IR spectral data are found to be in accordance with experimental values. In
addition, its UV–visible and fluorescence spectral measurements prove that the compound exhibits good
absorption and fluorescence properties. Also, it shows positive solvatochromic effect when the solvent
polarity was varied from non-polar to polar.
Received 24 October 2013
Received in revised form 29 December 2013
Accepted 5 January 2014
Available online 11 January 2014
Keywords:
Nicotinonitrile
Crystal structure
DFT calculation
Fluorescence
Ó 2014 Elsevier B.V. All rights reserved.
Solvatochromism
Introduction
their applications in organic light emitting diodes (OLEDs), fluores-
cent probes and fluorescent sensors [1,2]. For such applications,
In the recent years, there has been a considerable attention
among the researchers to synthesize and develop new -conju-
gated materials displaying promising luminescent properties.
the luminescent properties of the materials can be readily tuned
by structural modifications to attain required electronic properties.
Obviously, on the basis of donor–acceptor (DA) concept, one can
develop materials with unusual electrochromic, photochromic,
luminescent or nonlinear optical properties by the incorporation
of aromatic or heteroaromatic ring containing required electronic
properties [3–6].
p
Thus, search for novel luminescent compounds is important for
⇑
Corresponding author. Tel.: +91 8242474046; fax: +91 8242474033.
E-mail addresses: avachem@gmail.com, avadhikari123@yahoo.co.in, avchem@
nitk.ac.in (A.V. Adhikari).
1386-1425/$ - see front matter Ó 2014 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.saa.2014.01.006

T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
231
Table 1
2-methoxy-3-cyanopyridine acts as an electron deficient lumines-
cent core (acceptor) and two substituents, viz. 4-methylphenyl and
4-methoxyphenyl groups attached to 2-methoxy-3-cyanopyridine
core, act as electron donor moieties, leading to a good donor–
acceptor networking. The newly designed compound 2 was syn-
thesized from 1-(4-methoxy-phenyl)-3-p-tolyl-propenone (1) by
reacting it with malononitrile in basic medium. Its structure was
established using 1H NMR, FTIR, mass spectral as well as elemental
analyses and its photophysical properties were investigated by
UV–visible, and fluorescence spectroscopy. Also, the solvatochro-
mic behaviour of the compound was studied in various solvent sys-
tems. Further, its 3-D structure, shape and nature of short contacts
were investigated by single crystal X-ray study. Finally, its DFT cal-
culations were carried out to obtain optimized geometry and the-
oretical IR stretching vibrations.
Crystal and structure refinement data for compound (2).
Compound
2
Formula
C
21H18N2O2
Formula weight
CCDC number
Temperature (K)
Crystal form
Colour
Crystal system
Space group
a (Å)
330.38
933190
296 (2)
Block
Yellow
Monoclinic
P21/c
7.9324(2)
14.7056(5)
14.7951(5)
90
97.340(2)
90
b (Å)
c (Å)
a
(°)
b (°)
(°)
c
Volume (Å3)
Z
97.340(2)
4
1.282
Density (g cmÀ3
)
Experimental details
l
(mmÀ1
)
0.083
F (000)
696
Materials and measurements
hmin,
À9,9
max
kmin,
À18,17
À18,18
3370
max
The infrared spectrum of compound 2 was recorded on a Nicolet
Avatar 5700 FTIR (Thermo Electron Corporation). UV–visible and
fluorescence spectra were taken in GBC Cintra 101 and Perkin
Elmer LS55 fluorescence spectrophotometers in different non-
polar and polar organic solvents. 1H NMR spectrum was recorded
on a Bruker Avance DPX spectrometer at 300 MHz using DMSO-
d6 as the solvent with Tetramethylsilane (TMS) as internal stan-
dard, and data are reported in the order: chemical shift (ppm),
number of protons, multiplicity (s, singlet; d, doublet; dd, doublet
of doublet; t, triplet; q, quartet; m, multiplet; br, broad), approxi-
mate coupling constant (J) in hertz, and assignment of a signal.
Mass spectrum was recorded on Agilent technologies LC/MSD Trap
XCD mass spectrometry. An elemental analysis was performed on a
Flash EA1112 CHNS analyser (Thermo Electron Corporation).
Analytical thin layer chromatography (TLC) was performed on
pre-coated silica gel plates (Merck 60 Kieselgel F 254) and visual-
ised with UV light. DFT calculations were carried out by using
Turbomole software package.
lmin,
max
Reflections collected
Independent reflections
R_all, R_obs
2572
0.0579,0.046
0.1291,0.1182
À0.175,0.222
1.073
wR2_all, wR2_obs
D
qmin, max (e ÅÀ3
)
GOOF
Pyridine is an interesting stable n-type heterocyclic system,
which has attracted attention of many researchers for the design
of new conjugated materials [7–16]. In addition, since pyridine is
a highly electron-deficient heterocycle, it imparts good electron-
transporting ability and brings an excellent optical properties,
when it is present in donor and acceptor (DA) type conjugated sys-
tems. Further, field of pyridine has been of much interest owing to
its high thermal as well as chemical stability. In effect, the presence
of highly electron withdrawing nitrile (CN) substituent on the pyr-
idine ring can further promote its electron-transporting nature
[17]. In view of the observed fact that cyanopyridine is an attrac-
tive molecule with good electron transporting and photophysical
properties, many of its derivatives were shown to possess good
thermal and photochemical stability [18], high luminescence
efficiency and novel optoelectronic properties [18]. Also, it was re-
ported that insertion of an electron withdrawing cyanopyridine
ring in a DA type molecular network lowers its band gap [17].
Against this background, Bagley et al. synthesized various cyano-
pyridine derivatives bearing easily-interchangeable electron-
donating and electron-accepting groups, based on DA concept
and investigated their photoemissive properties [19]. Interestingly,
many cyanopyridine derivatives were found to possess good tune-
able photophysical behaviour and excellent quantum yields.
Motivated by the above findings, and keeping in view of
developing new cyanopyridine based luminescent materials, we
have designed a new DA type compound, viz. 2-methoxy-6-(4-
methoxy-phenyl)-4-p-tolyl-nicotinonitrile (2). In the new design,
Synthesis
1-(4-Methoxy-phenyl)-3-p-tolyl-propenone (1)
The 4-methoxyacetophenone (1 equivalent) and 4-methylbenz-
aldehyde (1 equivalent) were taken in 5 mL of ethanol. To this 1 mL
of aqueous potassium hydroxide (1.2 equivalents) solution was
added slowly. Reaction mixture was then stirred at room temper-
ature for 4 h. The precipitated product was filtered, washed with
water and recrystallized from methanol. White solid, yield 92%,
m.p. 197–198 °C. IR (ATR, cmÀ1): 2917, 2841, 1651, 1253, 1019,
804. Anal. Calcd. For. C17H16O2: C, 80.93; H, 6.39; Found: C.
81.09; H. 6.44.
2-Methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile (2)
1-(4-Methoxy-phenyl)-3-p-tolyl-propenone (1) (1 equivalent)
was added slowly to a freshly prepared solution of sodium
OMe
CN
N
O
Malononitrile
NaOMe, rt
MeO
Me
MeO
Me
1
2
Scheme 1. Synthesis of 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile.

232
T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
Fig. 1. FTIR spectrum of compound 2.
Fig. 2. 1H NMR spectrum of compound 2 in DMSO-d6 (300 MHz).
methoxide (20 mmol of sodium in 10 mL of methanol) while stir-
ring. Malononitrile (1.1equivalent) was then added with continu-
ous stirring at room temperature until the precipitate separates
out. The solid separated was collected by filtration, washed with
methanol and recrystallized from chloroform. Yellow solid, yield
76%, m.p. 188–189 °C. 1H NMR (300 MHz, DMSO-d6) d (ppm) 8.24
(d, J = 9 Hz, 2H, ArAH), 7.72 (s, 1H, ArAH (Pyridine)), 7.64 (d,
J = 9 Hz, 2H, ArAH), 7.39 (d, J = 9 Hz, 2H, ArAH), 7.08(d, J = 9 Hz,
2H, ArAH), 4.13 (s, 3H, AOCH3, Pyridine), 3.99 (s, 3H, AOCH3,
Phenyl), 2.41 (s, 3H, ACH3, Phenyl). LC/MS (m/z): found, 331.3
([M + H]+); Calcd. for C21H19N2O2, 331.3. IR (ATR, cmÀ1): 2948,
2856, 2218, 1543, 1445, 1014, 822. Anal. Calcd. For C21H18N2O2:
C, 76.34; H, 5.49; N, 8.48; Found: C. 76.18; H. 5.8; N.8.43.
tolyl-nicotinonitrile (2) in chloroform at room temperature, fol-
lowed by slow evaporation of solvent through a parafilm plastic
containing pinholes. A crystal of suitable size was mounted using
a Mitigen micromount, and single-crystal data collection was done
on a Bruker Smart X2S bench-top diffractometer equipped with a
micro-focus Mo K
a radiation (k = 0.71073) at room temperature
[20]. The machine was operated at 50 kV and 1 mA. Data reduction
was performed using SAINTPLUS. Scaling, absorption correction
was done using SADABS, all embedded in the Apex2 software suite
[20]. The crystal structure was solved by direct methods using XS
and the structure refinement was done using XL in the SHELXTL
package [21]. The position and thermal parameters of all the
non-hydrogen atoms were refined. The hydrogen’s were fixed in
geometrically calculated positions and refined isotropically. The
ORTEP diagrams and packing diagrams were created using
Mercury 3.0 and POV ray. Crystal and experimental data for com-
pound 2 are listed in Table 1. Its molecular structure is shown in
Scheme 1.
Structure determination and refinement
A single crystal of dimension 0.25 Â 0.23 Â 0.20 mm3 was
grown by dissolving the 2-methoxy-6-(4-methoxy-phenyl)-4-p-

T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
233
Fig. 3. Mass spectrum of compound 2.
Table 2
Selected bond lengths (Å) and angles (°) for Compound 2.
Bond lengths (Å)
O1AC1
1.3660(19)
1.419(2)
C41AC7
C51AC6
C81AC9
C91AC21
C121AC13
C131AC14
C151AC18
C161AC17
C171AH17
C201AH20C
1.475(2)
1.378(2)
1.409(2)
1.425(2)
1.390(2)
1.382(2)
1.508(2)
1.380(2)
0.9300
O11AC19
O21AC8
O21AC20
N11AC7
N11AC8
N21AC21
C11AC2
C11AC6
C21AC3
1.3433(18)
1.4323(19)
1.3549(18)
1.3129(19)
1.141(2)
1.380(2)
1.381(2)
1.376(2)
0.9600
Bond angles (°)
C11AO11AC19
C81AO21AC20
C71AN11AC8
O11AC11AC2
O11AC11AC6
C21AC11AC6
C11AC21AC3
N11AC71AC4
N11AC71AC11
O21AC81AN1
O21AC81AC9
N11AC81AC9
C31AC21AH2
C21AC31AH3
C21AC31AC4
C31AC41AC5
C31AC41AC7
C41AC51AC6
C41AC71AC11
117.64(13)
118.13(13)
117.85(12)
115.99(13)
124.72(14)
119.30(14)
120.43(14)
115.93(12)
121.50(12)
120.67(13)
114.96(13)
124.37(13)
120.00
C81AC91AC10
C81AC91AC21
118.07(13)
118.76(13)
120.74(12)
122.45(12)
118.19(13)
121.91(14)
179.19(17)
117.47(14)
117.19(12)
123.16(12)
121.02(13)
109.00
122.06(12)
109.00
119.36(12)
120.14(14)
121.14(15)
119.00
C111AC101AC12
C101AC121AC13
C131AC121AC17
C131AC141AC15
N21AC211AC9
C141AC151AC16
C91AC101AC11
C101AC91AC21
C71AC111AC10
O21AC201AH20A
C91AC101AC12
H20B1AC201AH20C
C101AC121AC17
C121AC131AC14
C141AC151AC18
C41AC31AH3
Fig. 4. ORTEP diagram of 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonit-
rile (2) with numbering scheme (here ‘A’, ‘B’, and ‘C’ indicate 4-methylphenyl-,
pyridyl- and 4-methoxyphenyl-rings, respectively).
Results and discussion
Synthesis
The synthetic rout for the preparation of new compound 2 is de-
picted in Scheme 1. The compound 2 was obtained in good yield
when 1-(4-methoxy-phenyl)-3-p-tolyl-propenone (1) was treated
with malononitrile at room temperature in presence of sodium
methoxide as catalyst. Further, its chemical structure was con-
firmed by using FTIR, 1H NMR, mass spectral and elemental analy-
ses. Finally, its three dimensional structure was determined with
the help of single crystal X-ray diffractometer.
119.00
121.54(15)
116.81(14)
120.81(13)
122.26(15)
122.57(13)
H18A1AC181AH18C
109.00
of aromatic pyridine ring. Also, three types of singlet were ob-
served; one singlet at 4.13 ppm for three protons -OMe of pyridine,
a second singlet resonated at 3.99 ppm for three protons -OMe of
phenyl, and a third singlet appeared at 2.41 ppm for three protons
of -Me of phenyl, confirm the formation of compound 2. Finally, its
structure was confirmed by mass spectral analysis and the exper-
imentally obtained mass 331.3 (M + H)+ is in agreement with that
of the calculated mass (Fig. 3).
Spectroscopic properties
The structure of compound 2 was established by FTIR, 1H NMR
and mass spectroscopic techniques. Its FTIR spectrum shows two
strong IR absorption bands at 2948 and 2856 cmÀ1 that correspond
to asymmetric and symmetric CAH stretching vibrations of meth-
oxy group (Fig. 1). Further, a strong IR absorption band at
2218 cmÀ1 indicates the presence of cyano group in its molecular
structure. Also, the absorption band at 1543 cmÀ1 accounts for
Crystal structure of 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-
nicotinonitrile (2)
@
C
@
N stretching, confirming the formation of pyridine ring. The
compound 2, in its 1H NMR spectrum (Fig. 2) shows unique reso-
nances at 8.24, 7.64, 7.39 and 7.08 ppm for the protons of aromatic
moieties. The appearance of a singlet at 7.72 ppm is for one proton
Single-crystal X-ray study reveals that compound (2) crystal-
lizes in monoclinic space group P21/c with cell parameters are

234
T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
Table 3
Intra and intermolecular C1AHÁ Á ÁN interactions in the crystal structure of compound 2.
Compound
2
D1AHÁ Á ÁA
DAH/Å
HÁ Á ÁA/Å
2.480
2.520
2.591
DÁ Á ÁA/Å
2.798(2)
3.383(2)
3.116(2)
\ DAHÁ Á ÁA/°
100.00
154.00
115.00
Symmetry
C3AH3Á Á ÁN1
0.930
0.930
0.960
x, y, z
C17AH17Á Á ÁN2
C20AH20AÁ Á ÁN2
Àx + 1, y + 1/2, Àz + 1/2
x, Ày + 1/2, z + 1/2
Table 4
Dielectric constant, photophysical properties, and Stoke shift values of compound 2 in
different solvents.
Solvent
Dielectric constant
(25 °C)
kabs
(nm)
kem
(nm)
Stoke shift
(nm)
Hexane
1.87
4.80
6.02
7.58
20.70
32.70
334
341
335
339
340
338
343
338
344
375
392
394
400
403
405
409
406
412
41
51
59
61
63
67
66
68
70
Chloroform
Ethyl acetate
Tetrahydrofuran
Acetone
Methanol
Dimethylformamide 36.71
Acetonitrile
Dimethyl
37.5
46.68
sulphoxide
Fig. 5. Crystal structure of compound
interactions.
2
depicting CAHÁ Á ÁN intermolecular
at position-3 on ‘B’ ring of one molecule and the nearby methoxy
protons at position-2 of ‘B’ ring of other molecule) hydrogen bonds
and their values are tabulated in Table 3. Packing diagram, depict-
ing CAHÁ Á ÁN intermolecular interactions and their values is shown
in Fig. 5. Also, the crystal assembly of 2, as shown in Fig. 6(a) con-
a = 7.9324(2) (Å), b = 14.7056(5) Å, c = 14.7951(5) Å, V = 97.340(2)
Å, Z = 4 (Table 1). Fig. 4 shows the labelled ORTEP diagram of the
compound. In the figure, the three rings are distinguished by label-
ling with alphabets ‘A’, ‘B’, and ‘C’. This labelling is useful for
explaining the intermolecular interactions in the later stages. How-
ever, from the X-ray analysis data, it is evident that the molecule is
not planar and but distorted. Interestingly, the 4-methylphenyl
ring substituted at the position-4 of the central pyridine ring
tains CAHÁ Á Á
the formation of dimers in its structure. In the dimer, the methoxy
group of ‘B’ ring is interacting with the cloud of the other ‘B’ ring
and vice versa (C(20)AHÁ Á ÁCgB = 3.159 Å, where CgB is the centroid
of ‘B’ ring). In fact, the contribution of interactions in crystal
Á Á Á
assembly is noteworthy. In the crystal assembly of 2, -electron
cloud of ‘B’ ring is involving face–face to interactions with the
-electron cloud of ‘C’ ring of the nearby molecule with a separa-
p
and
p
Á Á Á
p short contacts, which is responsible for
p
p
p
p
makes a torsion angle
the central pyridine ring, while the other 4-methoxyphenyl ring,
substituted at the position-6, forms a torsion angle [N(1), C(7),
v
[C(9), C(10), C(12), C(13)] of À47.65° with
p
tion of 3.753 Å (Fig. 6(b)).
v
C(4), C(3)] of À14.97°, which is less than the previous one. Further,
bond length and bond angle values are all within the expected
range, as shown in Table 2. From the data of Table 2, it is observed
that CAC, CAN and CAO bond length values in the three ring sys-
tem are possessing partial double bond character, which clearly
Photophysical properties
UV–visible absorption (10À5 M) and fluorescence emission
(10À6 M) spectra were recorded for compound 2 in hexane, chloro-
form, tetrahydrofuran (THF), acetone, methanol (MeOH), dimethyl-
formamide (DMF) and dimethyl sulfoxide (DMSO), in order to
explore its photophysical properties and its molecular interactions
with different non-polar and polar organic solvents. These solvents
were selected on the basis of increasing order of their dielectric
constant values. The absorption and fluorescence spectral data
along with the dielectric constants of solvents are tabulated in
Table 4. Figs. 7 and 8 show the UV–visible absorption and
indicates that the
in delocalization.
p-electrons in the three ring system are involved
Further, it is interesting to note that the structure is stabilized
by intra-molecular C3AH3Á Á ÁN1 hydrogen bond (Table 3), besides
two kinds of intermolecular, i.e. C17AH17Á Á ÁN2 (formed by the
nitrogen atom of cyano group at position-3 on ‘B’ ring of one mol-
ecule and the nearby aromatic proton of ‘A’ ring of other molecule)
and C20AH20AÁ Á ÁN2 (formed by the nitrogen atom of cyano group
Fig. 6. Crystal structure of compound 2 representing (a) CAHÁ Á Áp, and (b) pÁ Á Áp short contacts.

T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
235
1.0
0.8
0.6
0.4
0.2
0.0
Hexane
Chloroform
EtOAc
THF
Acetone
MeOH
DMF
ACN
DMSO
Fig. 10. Theoretically obtained FTIR spectrum of compound 2.
300
350
400
450
Wavelength (nm)
observed under their excitation wavelengths. Similar to absorption
spectra, the fluorescence spectra of compound 2 showed signifi-
cantly larger solvatochromic effect. There was an appreciable
change in emission maxima with the variation of solvent systems
from non-polar (hexane) to highly polar (DMSO) solvent with
Stokes shift of 50–75 nm. Also, there was a considerable red shift-
ing of emission bands in the fluorescence spectrum, which is
attributed to the enhanced interaction between fluorescent mole-
cule and polar solvent. However, in case of acetonitrile no such
observation was made due to its weak interactions with the chro-
mophore. Also, the material was found to be blue fluorescent under
UV lamp (k = 365 nm). From the results of photophysical studies it
can be concluded that compound 2 is a promising material for its
applications in organo-electronic devices.
Fig. 7. UV–visible spectra of compound 2 in different solvents (10À5 M).
1000
Hexane
Chloroform
EtOAc
THF
800
Acetone
MeOH
DMF
ACN
600
DMSO
400
200
Theoretical study
0
The geometry optimization and theoretical IR stretching vibra-
tions of molecule 2 were evaluated by density functional theory
(DFT) calculations at the def-TZVP level [22–30]. The optimized
structure and the frontier molecular orbital profile of 2 are shown
in Fig. 9. The study suggests that the compound 2 possesses dis-
torted molecular structure, wherein 4-methylphenyl ring substi-
tuted at the position-4 of the central pyridine ring possesses a
non-planar arrangement, while 4-methoxyphenyl ring substituted
at position-6 of central pyridine ring is having nearly planar
arrangement. This observation may be attributed to the interaction
exerted by the ACN functional group at position-3 of pyridine ring.
Therefore, the HOMO is mainly localized on the 4-methoxyphenyl
and central pyridine ring, while the LUMO is delocalized along
the whole molecule, indicating that the molecule possesses better
intra-molecular charge transfer ability. Fig. 10 shows the calcu-
lated IR-spectrum of 2. Here, the peaks within the range of
1600–650 cmÀ1 are attributed to the aromatic CAC and CAN bond
vibrations. Further, the peaks centred at 2220 cmÀ1 and 3000 cmÀ1
are due to the stretching vibrations of cyano and aromatic CAH
groups, respectively. Thus, theoretical calculated IR stretching
vibrations for the compound 2 is in accordance with that of the
experimentally obtained results (as shown in Fig. 1).
350
400
450
500
550
Wavelength (nm)
Fig. 8. Fluorescence spectra of compound 2 in different solvents (10À6 M).
Fig. 9. Optimized geometric structure and frontier molecular orbital diagram of 2.
fluorescence spectra in different solvents, respectively. In its
absorption spectra, the compound showed one intense absorption
band in UV region both in non-polar and polar solvents and the po-
sition of the absorption band lies in between 301 and 344 nm.
Conclusion
In the present study,
a new luminescent material, viz.
These absorption bands were attributed to a
p
?
p⁄ electronic
2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile (2) was
successfully synthesized using a simple route and was well-charac-
terised with spectral techniques. Its single crystal and DFT study
revealed the existence of non-planar structure. Theoretically calcu-
lated IR stretching vibrations are in well agreement with that of the
experimental results. In addition, its photophysical measurements
transition occurring in it. Table 3 shows that the absorption band
(kabs) has shifted to a longer wavelength i.e. from 301 nm to
343 nm, with the increase in solvent polarity.
In its fluorescence spectra, an intense blue emission band
appearing between 375 nm (hexane) and 412 nm (DMSO) has been

236
T.N. Ahipa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 124 (2014) 230–236
[7] J.G. Liu, L.F. Wang, H.X. Yang, H.S. Li, Y.F. Li, L. Fan, J. Polym. Sci., Part A: Polym.
Chem. 2004 (1845) 42.
[8] G. Liu, Q.D. Ling, E.T. Kang, K.G. Neoh, D.J. Liaw, F.C. Chang, J. Appl. Phys. 102
(2007) 024502.
[9] S. Chen, X. Xu, Y. Liu, G. Yu, X. Sun, W. Qiu, Adv. Funct. Mater. 15 (2005) 1541.
[10] X. Pan, S. Liu, H.S.O. Chan, S.C. Ng, Macromolecules 38 (2005) 7629.
[11] K.L. Wang, D.J. Liaw, W.T. Liou, W.T. Chen, Dyes Pigments 78 (2008) 93.
[12] D.J. Liaw, K.L. Wang, F.C. Chang, Macromolecules 40 (2007) 3568.
[13] K.L. Wang, D.J. Liaw, W.T. Liou, S.T. Huang, Polymer 49 (2008) 1538.
[14] J.X. Yang, X.T. Tao, X.Y. Chun, X.Y. Yun, L. Wang, Z. Liu, J. Am. Chem. Soc. 127
(2005) 3278.
indicate that it is a good absorbent and fluorescent material with
positive solvatochromic behaviour in both polar and nonpolar
solvents. From the results it can be concluded that compound 2
is a promising candidate for its applications in organo-electronic
devices.
Supplementary material
Crystallographic data for the structure reported in this article
have been deposited with the Cambridge Crystallographic Data
Centre with the deposition number 933190. A copy of the data
can be obtained free of charge from the Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (Fax: +44 1223 336 033; E-mail: de-
posit@ccdc.cam. ac.uk or www.ccdc.cam.ac.uk).
[15] M. Sonntag, P. Strohriegl, Chem. Mater. 16 (2004) 4736.
[16] N. Zaami, C. Slugovc, A. Pogantsch, F. Stelzer, Macromol. Chem. Phys. 205
(2004) 523.
[17] K.A. Vishnumurthy, M.S. Sunitha, K. Safakath, R. Philip, A.V. Adhikari, Polymer
52 (2011) 4174.
[18] M. Matsui, A. Oji, K. Hiramatsu, K. Shibata, H. Muramatsu, J. Chem. Soc. Perkin
Trans. 2 (1992) 201.
[19] M.C. Bagley, Z. Lin, S.J.A. Pope, Chem. Commun. (2009) 5165.
[20] Bruker, APEX2, GIS, SADABS and SAINT Bruker AXS Inc., Madison, Wisconsin,
USA, 2009.
[21] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112.
[22] R. Ahlrichs, M. Bär, M. Häser, H. Horn, C. Kölmel, Chem. Phys. Lett. 162 (1989)
165.
[23] O. Treutler, R. Ahlrichs, J. Chem. Phys. 102 (1995) 346.
[24] M.v. Arnim, R. Ahlrichs, J. Comp. Chem. 19 (1998) 1746.
[25] K. Eichkorn, O. Treutler, H. Öhm, M. Häser, R. Ahlrichs, Chem. Phys. Lett. 240
(1995) 283.
Acknowledgement
The authors are grateful to the NITK, Surathkal and Solid State
Structural Chemistry, IISC, Bangalore, India.
References
[26] K. Eichkorn, O. Treutler, H. Oehm, M. Haeser, R. Ahlrichs, Chem. Phys. Lett. 242
(1995) 652.
[27] K. Eichkorn, F. Weigend, O. Treutler, R. Ahlrichs, Theor. Chem. Acc. 97 (1997)
119.
[1] D.R. Kanis, M.A. Ratner, T.J. Marks, Chem. Rev. 94 (1994) 195.
[2] M.M.M. Raposo, A.M.R.C. Sousa, G. Kirsch, P. Cardoso, M. Belsley, E. de Matos
Gomes, A.M.C. Fonseca, Org. Lett. 8 (2006) 3681.
[3] V.P. Rao, A.K-Y. Jen, J.B. Caldwell, Tetrahedron Lett. 35 (1994) 3849.
[4] A. Facchetti, L. Beverina, M.E. Van-der Boom, E.G. Dutta, G.A. Pagani, T.J. Marks,
J. Am. Chem. Soc. 128 (2006) 2142.
[28] P. Deglmann, K. May, F. Furche, R. Ahlrichs, Chem. Phys. Lett. 384 (2004) 103.
[29] P. Deglmann, F. Furche, R. Ahlrichs, Chem. Phys. Lett. 362 (2002) 511.
[30] P. Deglmann, F. Furche, J. Chem. Phys. 117 (2002) 9535.
[5] Z.R. Grabowski, K. Rotkiewicz, W. Rettig, Chem. Rev. 103 (2003) 3899.
[6] B.C. Thompson, K.A. About, J.R. Reynolds, K. Nakatani, P. Audebert, New J.
Chem. 29 (2005) 1128.