Quantum chemical simulations of solvent influence on UV-vis spectra and orbital shapes of azoderivatives of diphenylpropane-1,3-dione

Article abstract of DOI:10.1016/j.saa.2010.12.080

The DFT modeling of novel synthesized azoderivatives of β-diketones - 2-(2-(2-hydroxyphenyl)hydrazono)-1,3-diphenylpropane-1,3-dione (1), 2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1,3-diphenylpropane-1,3-dione (2), 3-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylid

Full text of DOI:10.1016/j.saa.2010.12.080

Spectrochimica Acta Part A 78 (2011) 1287–1294
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Quantum chemical simulations of solvent influence on UV–vis spectra and orbital
shapes of azoderivatives of diphenylpropane-1,3-dione
W. Kuznika, I.V. Kitykb,∗, M.N. Kopylovichc, K.T. Mahmudovc, K. Ozgad, G. Lakshminarayanae,
A.J.L. Pombeiroc,∗∗
a Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Gliwice, Poland
b Electrical Engineering Department, Czestochowa University of Technology, Av. Armii Krajowej 17/19, PL-42200 Czestochowa, Poland
c Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1049–001 Lisbon, Portugal
d Czestochowa University of Technology, Armii Krajowej Av. 36B, 42200 Czestochowa, Poland
e Department of Materials Science – WW3, University of Erlangen-Nuremberg, Erlangen 91058, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 December 2010
Accepted 28 December 2010
The DFT modeling of novel synthesized azoderivatives of ␤-diketones – 2-(2-(2-hydroxyphenyl)-
hydrazono)-1,3-diphenylpropane-1,3-dione (1), 2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1,3-di-
phenylpropane-1,3-dione (2), 3-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)hydrazinyl)-2-hydroxy-5-
nitrobenzene sulfonic acid (3), 2-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)hydrazinyl)benzene-
sulfonic acid (4), 2-(2-(1,3-dioxo-1,3-diphenylpropan -2-ylidene)hydrazinyl)benzoic acid (5), 2-(2-
(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1,3-dione (6) were performed. The collected
information confirms that 1–5 exist in hydrazo form, being stabilized by the intramolecular hydrogen
bonds in DMSO solution and solid phase, while 6 exists in mixed enol-azo and hydrazo tautomeric forms,
the latter dominating in more polar solvents. The relative stability of various tautomeric and izomeric
forms of the symmetric 1–5 and unsymmetric 6 azoderivatives of ␤-diketones is calculated based on
the density functional theory (DFT). Polarizable Continuum Model was used to simulate solvatochromic
effects. Solvents of different polarities were used to collect experimental spectra, and the same solvents
were chosen for the PCM calculations. The optical properties of 1–6 have been investigated by density
functional theory and its electronic absorption bands have been assigned by time-dependent density
functional theory (TD-DFT).
Keywords:
Azoderivatives of ␤-diketones
Solvatochromic effect
Tautomers
DFT calculations
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
forms (enol-azo, keto-azo and hydrazo) [8–13] with conjugated
donor–␲–acceptor motif, which already made them promising can-
The search for new materials in which low-energy external
effects can significantly change the overall behavior, for example
their optical (including solvatochromic) properties, conductivity,
electrochemical potentials etc. is a subject of the extensive theo-
retical and experimental investigations in the recent decades [1–3].
The strategy used to design the substances with the desired proper-
ties usually involves combination, within the same molecule, donor
and acceptor groups at the terminal positions of a ␲-bridge to cre-
ate polarized motif which is highly sensitive to the subtle external
influences and can also exhibit some nonlinear properties [4–7].
In the search of new motifs possessing such properties we have
found that azoderivatives of ␤-diketones (ADB) are good poten-
tial candidates. Theoretically ADB can exist in three tautomeric
didates for such applications as bistate molecular switches [14–21],
optical recording media and spin-coating films [22,23] or photolu-
minescent [24] materials. In our recent work [11] we have found
that ADB containing a hydroxyl group in ortho-position to the
hydrazo group and formed from the unsymmetrical ␤-diketones,
exist in solution in two distinct tautomeric forms namely enol-azo
and hydrazo-, and that a ratio between these forms depends on the
solvent used as well as on temperature. On the other hand, it was
shown that in the solid state these ADB compounds are stabilized
only in hydrazo form [11]. It was assumed that the tautomers in
solution are stabilized by a strong intramolecular resonance assisted
hydrogen bond (RAHB), and that the tautomeric balance can play an
important role for many applications involving subtle transitions
[14–21].
Thus, we decided to extend this study towards detailed
investigation of solvatochromic properties of the other
newly synthesized ADB, namely 2-(2-(2-hydroxyphenyl)
hydrazono) -1,3-diphenylpropane-1,3-dione (1), 2-(2-(2-hydroxy-
4-nitrophenyl)hydrazono)-1,3-diphenyl propane-1,3-dione (2),
∗
Corresponding author. Tel.: +48 601 50 42 68; fax: +48 34 3250 821.
Corresponding author. Tel.: +351 218419237; fax: +351 21846445.
E-mail addresses: ikityk@el.pcz.czest.pl (I.V. Kityk), pombeiro@ist.utl.pt
∗∗
(A.J.L. Pombeiro).
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.12.080

1288
W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
Scheme 1. Azoderivatives of ␤-diketones considered in this work.
3-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)hydrazinyl)-2-hy-
droxy-5-nitrobenzenesulfonic acid (3), 2-(2-(1,3-dioxo-1,
2.2. Calculation procedure
3-diphenylpropan-2-ylidene)hydrazinyl) benzenesulfonic acid (4),
2-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)hydrazinyl)
benzoic acid (5), 2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-
1-phenylbutane-1,3-dione (6). As can be seen (Scheme 1), these
compounds offer better ␲-electron delocalization across the
donor–acceptor links (enol-azo ꢀ hydrazo transition) in com-
parison to the ones studied by us before [11]. Substitutions at
the ␤-diketone fragment and aromatic part of molecule have
been made to ensure that the ADB indeed acts as a ␲-conjugated
backbone. Various aromatic donors and acceptors have been used
to cover a wide representation of the ADB group.
All the DFT calculations were performed using GAUSSIAN09
[28]. GABEDIT 2.2.8 Graphical User Interface [29] was used to gen-
erate input files and to produce graphs from output files. The
calculations were performed at 6-31G (d) DFT B3LYP level with PCM
(Polarizable Continuum Model) [30–33] applied to simulate solva-
tochromism. Time-dependent density functional theory (TD-DFT)
was used to simulate UV–vis absorption spectra.
2.3. Synthesis of the azoderivatives of ˇ-diketones
The compounds were prepared via the Japp–Klingemann reac-
tion [34–36] involving diazotization of aromatic amines with
following azocoupling of thus formed diazonium salt and ␤-
diketones in water solution containing sodium hydroxide [12,37].
2. Experimental
2.3.1. Diazotization
2.1. Equipment and materials
A 0.025 mol portion of substituted aniline was dissolved in
50 mL of water and then 1.00 g of crystalline NaOH was added.
The solution was cooled in an ice bath to 273 K and then 1.725 g
(0.025 mol) of NaNO2 was added; after that 5.00 mL (33%) HCl was
added in portions for 1 h. The temperature of the mixture should not
exceed 278 K. The resulting diazonium solution was used directly
in the following coupling procedure.
The 1H and 13C NMR spectra were recorded at room temperature
on a Bruker Avance II + 300 (UltraShieldTM Magnet) spectrometer
operating at 300.130 and 75.468 MHz for proton, and carbon-
13, respectively. The chemical shifts are reported in ppm using
tetramethylsilane as an internal reference. The infrared spectrum
(4000–400 cm−1) was recorded on a Nicolet FT-IR Nexus spec-
trophotometer using KBr pellets. Carbon, hydrogen, and nitrogen
elemental analyses were carried out by the Microanalytical Service
of the Instituto Superior Técnico.
UV–vis spectra were recorded in methanol, acetonitrile,
dichloromethane and n-hexane (HPLC grade) solutions (concentra-
tions approximately 50 mg/L) in standard 1 cm path length quartz
cell using HP 8452A UV–vis Diode Array Spectrophotometer in the
range 190–820 nm with spectral resolution 2 nm.
Cyclic voltammetry measurements were performed on
AUTOLAB PGSTAT20 potentiostat–galvanostat (EcoChemie,
Netherlands). Platinum wire (ꢀ = 1 mm) with a working area of
approximately 0.10 cm2 was used as a working electrode. Silver
wire was used as a quasi-reference electrode, while platinum
coil served as an auxiliary one. Silver quasi-reference electrode’s
potential was calibrated using ferrocene as an internal standard.
The electrolyte solution used was 0.2 M Bu4NPF6 (Aldrich 98%
pure) in acetonitrile (POCh 99.8% HPLC grade). Prior to the mea-
surements the solution was purged with argon to remove residual
oxygen. As the ferrocene redox pair potential with respect to
free electron in vacuum at rest is known [25–27] oxidation and
reduction potentials with respect to the ferrocene redox pair were
recalculated to HOMO and LUMO energy levels.
2.3.2. Azocoupling
1.00 g (0.025 mol) of NaOH was added to a mixture of 0.025 mol
of ␤-diketone with 50 mL of water–ethanol (1:1, v/v). The solu-
tion was cooled in an ice bath to ca. 273 K, and a suspension of
4-substituted diazonium (see above) was added in three portions
under vigorous stirring for 1 h.
The identity of 1–6 was demonstrated by element analysis,
IR and 1H and 13C NMR spectrometry (for details see Supporting
Information).
3. Results and discussion
3.1. Synthesis of 1–6 and spectroscopic study
Usually ADB are synthesized by diazotization of aromatic
amines and coupling of thus formed diazonium salt with ␤-
diketone in the presence of sodium acetate (synthetic procedure
commonly known as a Japp–Klingemann reaction). However, in
our case this method gives a low yield of a highly impure prod-
uct. Therefore, we have modified the synthesis and used sodium
hydroxide instead of sodium acetate to get ␤-diketone carboan-

W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
1289
Scheme 2. Possible tautomeric equilibria for 6.
ion [12,37], that allowed us to get good yields of considerably pure
compounds.
MeOD and 78% enol-azo, 22% hydrazo in DMSO). The third tau-
tomeric form, viz. keto-azo, was not detected in solution under any
experimental conditions, presumably due to its lower stability in
comparison with the others. Hence, using those data, one can pre-
dict and tune the tautomeric equilibrium in the appropriate solvent.
Although 6 was proved to exist in solution as a mixture of two tau-
tomeric forms, IR spectrum (ꢁ(NH) and ꢁ(C N) vibrations at 3184
and 1527 cm−1, respectively) shows that in the solid state it is sta-
bilized in the hydrazo form (Scheme 2) similarly to the reported
analog [11].
The 1H NMR spectra of 1–5 prepared from symmetrical 1,3-
diphenylpropane-1,3-dione show only one set of signals for each
compound in DMSO, where the broad signal at ꢀ ca. 13.2–14.1 can
be assigned to N–NH adjacent to the aryl unit similarly to the
reported analogs [8–13,37–42]. Moreover, the presence of two C
O
resonances in 13C{ H} NMR spectra in the range of 185.36–195.72
and a single C N resonance at ca. 133.4–136.5 indicates that 1–5
exist in solution in the hydrazo form. In the solid state their IR spec-
tra reveal the presence of NH, C O, C O· · ·H and C N vibration at
ca. 2927–3448, 1684–1635, 1596–1623 and 1501–1596 cm−1, cor-
respondingly, indicating that 1–5 are stabilized in the H-bonded
hydrazone forms.
1
3.2. Cyclic voltammetry
HOMO and LUMO levels are summarized in Table 1. As oxida-
tion is a withdrawal of an electron from the studied molecule, it
informs one about the energy level of the electron, which is the
most easily available, that is the one described by HOMO orbital.
The oxidation potential is read from the graph and translated into
an absolute scale by multiplying by (−1) and adding 5.064 [43,44]
to yield HOMO energy level with respect to vacuum. LUMO level is
determined from the reduction peak using analogous procedure.
On the other hand, 1H NMR spectrum of 6 formed from unsym-
metric 1-phenylbutane-1,3-dione in MeOD-d4 and DMSO-d6 at
room temperature consists of two sets of signals, indicating that
in these solvents the compound exists as a mixture of two tau-
tomeric forms – enol-azo and hydrazo (Scheme 2) [11]. With an
increase in the polarity of solvents (MeOD < DMSO) the tautomeric
balance shifts to the hydrazo form (86% enol-azo, 14% hydrazo in

1290
W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
Table 1
HOMO and LUMO levels and energy gaps determined by the cyclic voltammetry.
1–6
HOMO [V]
LUMO [V]
Energy gap [eV]
Energy gap [nm]
1
2
3
4
5
6
3.5
3.1
3.2
3.1
3.1
3.5
5.5
5.7
5.4
5.7
5.5
5.2
2.0
2.6
2.2
2.6
2.4
1.7
628
472
584
475
522
715
3.3. DFT calculations
exception. The procedure to generate the absorption spectra was
as follows: first the geometry was optimized by the DFT method
with or without PCM, and then a TDDFT calculation was performed
using the previously obtained geometries.
Table 2 presents the static dipole moments of the DFT optimized
molecules. As can be seen, the functional groups included into the
␤-diketone fragment and aromatic part of the molecules influences
the LUMO levels and energy gap. Besides, the energy gap of sym-
metrical ADB (1–5) is higher than that for the unsymmetrical one
(6).
All the geometry optimization jobs converged to hydrazo form
regardless the polarity of solvent simulated by PCM, even if enolazo
form was used as an initial geometry (Fig. 1). A clear correlation
between molecules’ dipole moment and solvent polarity can be
seen in the calculation results (Table 2). The dipole moment gen-
erally increases with increasing solvent polarity, 2 being the only
3.4. UV–vis absorption spectra
The experimental and theoretical UV–vis absorption spectra are
depicted in Figs. 2–7. All the plots are charted according to the same
scheme: top panel: DFT-derived spectra, bottom panel: experi-
ments, grey line: no PCM used, black solid, dashed and dotted line:
data in acetonitrile, dichloromethane and n-hexane, respectively.
As it is a considerable amount of data (over forty curves altogether),
it will be commented in two separate sections: first focusing on
TDDFT alone, and second on solvatochromism and performance of
PCM model in properly addressing it.
3.4.1. Experimental data and the TDDFT simulations
In general, time-dependent DFT prediction (grey line, top panel)
is a good approximation of the absorption spectra of the studied
azo compounds. Even though the first peak is shifted approxi-
mately 40 nm to the red, which is a well known drawback of the
DFT method, all the main peaks are correctly simulated. In most
of the studied cases the relative peak intensities were adequately
described by the theoretical prediction, and correspondence with
experimental data is especially good for 4 (Fig. 5).
3.4.2. Solvatochromism and the CPM model performance
All the theoretical simulations show strong dependence on the
solvent chosen for the PCM calculation, except from 4, which is only
weakly correlated with solvent type used. Generally, the more polar
the solvent, the stronger batochromic shift which is clearly visible
especially in the violet to green range of the spectra. As this area is of
the greatest interest to practical applications, we will concentrate
on this part of the spectrum and only shortly comment on the ultra-
violet range. Theoretical prediction of the UV part of the spectrum
is highly satisfactory and accurate and it proves TDDFT potential
to be used in optically active material research. The absence of any
peak below 230 nm in dichloromethane solutions is merely a result
of light absorption by the solvent itself.
The visible region of the spectra, on the other hand, is more inter-
esting and posed quite a challenge to the DFT methods to predict. It
is probably due to the ability of these compounds to be present in
many different forms (Scheme 2). Also, the electrons can be highly
delocalized in these conjugated systems. For all the cases except
from 4 the peak lowest in energy is highly dependent upon the
solvent used in calculation, and the difference between n-hexane
(the least polar) and acetonitrile (the most polar) is approximately
30 nm. When looking at the 1 and 3 plots (Figs. 2 and 4) it would
seem that all the PCM-including calculations failed to compare the
Fig. 1. Initial, final and one of the intermediate geometries of 1 in a DFT geometry
optimization. The final, energetically preferable geometry is the hydrazo form.

W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
1291
Table 2
Static dipole moments of DFT optimized molecules.
Dipole moment [Debye]
1
2
3
4
5
6
Acetonitrile
Ethanol
Dichloromethane
n-Hexane
6.77
6.76
6.41
5.28
4.01
3.31
3.32
3.33
4.86
4.49
5.69
5.69
5.17
5.09
4.45
4.59
4.57
4.17
2.91
2.45
5.79
5.78
5.4
4.27
3.66
9.19
9.18
8.9
7.84
7.05
No PCM used
“ordinary” TDDFT – they show very strong solvatochromism, which
cannot be seen in the experimental spectra. However, a closer look
at 2, 5 and 6 reveals an interesting result. When the substance is in
polar solvent, a new peak emerges about 40 nm to the red from the
next peak, and the peaks relative intensity rises with solvent polar-
ity – it is higher in acetonitrile than in dichloromethane, and the
peak is absent from spectra measured in n-hexane. We believe it is
precisely the peak TDDFT simulation with PCM model predicted. It
1,0
B
TDDFT
E
D
TDDFT ACN
TDDFT DCM
TDDFT nHEX
A
C
0,5
0,0
200
250
300
350
400
450
500
550
Wavelength [nm]
1,0
0,5
0,0
B
ACN
DCM
nHEX
N
C
N
H
D
O
OH
A
O
200
250
300
350
400
450
500
550
Wavelength [nm]
Fig. 2. UV–vis absorption spectra of 1. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.
1,0
TDDFT
ACN TDDFT
DCM TDDFT
nHEX TDDFT
A
B
D
E
0,5
C
0,0
1,0
200
250
300
350
400
450
500
550
600
Wavelength [nm]
O2N
C
ACN
DCM
nHEX
A
B
D
N
N
H
O
OH
0,5
0,0
O
E
200
250
300
350
400
450
500
550
600
Wavelength [nm]
Fig. 3. UV–vis absorption spectra of 2. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.

1292
W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
Fig. 4. UV–vis absorption spectra of 3. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.
1,0
B
TDDFT
C
TDDFT ACN
TDDFT DCM
TDDFT nHEX
D
A
0,5
E
0,0
1,0
200
250
300
350
400
450
500
Wavelength [nm]
ACN
DCM
nHEX
HO3S
A
D
B
C
HN
E
N
0,5
0,0
O
O
200
250
300
350
400
450
500
Wavelength [nm]
Fig. 5. UV–vis absorption spectra of 4. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.
Table 3
Excited states of 2, 5 and 6.
First excited
states
Acetonitrile
Energy [nm]
Dichloromethane
Energy [nm]
n-Hexane
Energy [eV]
Oscillator
strength
Energy [eV]
Oscillator
strength
Energy [eV]
Energy [nm]
Oscillator
strength
2.654
2.853
2.989
3.091
2.64
467
435
415
401
470
432
0.8776
0.1171
0.708
0.0935
0.9734
0.0717
2.688
2.852
3.019
3.087
2.6788
2.93
462
435
411
402
463
423
0.7593
0.2007
0.5778
0.1928
0.9207
0.0985
2
5
6
2.876
3.034
3.17
2.797
2.9534
431
409
391
443
420
0.8742
0.0212
0.6286
0.4901
0.0024
2.932

W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
1293
D
1,0
0,5
A
TDDFT
B
TDDFT ACN
TDDFT DCM
TDDFT nHEX
C
0,0
1,0
200
250
300
350
400
450
500
Wavelength [nm]
O
ACN
DCM
nHEX
HO
A
B
D
HN
N
0,5
0,0
C
O
O
200
250
300
350
400
450
500
Wavelength [nm]
Fig. 6. UV–vis absorption spectra of 5. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.
D
1,0
0,5
C
ACN TDDFT
DCM TDDFT
nHEX TDDFT
TDDFT
A
B
0,0
1,0
200
250
300
350
400
450
500
550
600
Wavelength [nm]
ACN
DCM
nHEX
A
O
B
C
OH
H
N
D
N
0,5
0,0
O
NO2
200
250
300
350
400
450
500
550
600
Wavelength [nm]
Fig. 7. UV–vis absorption spectra of 6. Top panel: spectra predicted by 6-31G(d) BLYP DFT with or without PCM; bottom panel: experimental spectra, approx. 50 mg/L. ACN
– acetonitrile, DCM – dichloromethane, and nHEX – n-hexane.
seems that the excited states are affected by polar solvents and the
PCM model predicted it in all the cases, but in reality it took place
only in 2, 5 and 6. The first excited states in the predicted spectra
are strongest in polar solvents (Table 3), in n-hexane they are either
weak (6), negligibly small (5) or completely absent (2). Apparently
these molecules, when placed in polar solvents, can absorb photons
of two different energies: one predicted by the PCM model, and the
other one by TDDFT with no PCM used. Thus, to properly predict
those spectra both these calculations must be taken into account.
Neither of the two calculation procedures was able to predict the
whole spectrum (namely both peaks in the visible range), probably
because calculations are limited to only one molecule conforma-
tion/excitation, while numerous different conformations coexist in
real solutions.
4. Conclusions
In this work we present time-dependent density func-
tional theory approach to investigate the UV–vis spectra of
new organic compounds: azoderivatives of ␤-diketones – 2-(2-
(2-hydroxyphenyl)hydrazono)-1,3-diphenylpropane-1,3-dione
(1),
lpropane-1,3-dione
-2-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonic
2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1,3-dipheny-
(2), 3-(2-(1,3–dioxo-1,3-diphenylpropan
acid

1294
W. Kuznik et al. / Spectrochimica Acta Part A 78 (2011) 1287–1294
2-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)hydrazinyl) [7] N. Terkia-Derdra, R. Andreu, M. Sallé, E. Levillain, J. Orduna, J. Garin, et al., Chem.
(3),
A Eur. J. 6 (2000) 1199–1223.
benzenesulfonic acid (4), 2-(2-(1,3–dioxo-1,3-diphenylpropan
-2-ylidene)hydrazinyl)benzoic acid (5), 2-(2-(2-hydroxy-4-
nitrophenyl)hydrazono)-1-phenylbutane-1,3-dione (6). Polari-
zable Continuum Model was used to simulate solvatochromic
effects.
[8] A.M. Maharramov, R.A. Aliyeva, I.A. Aliyev, F.G. Pashaev, A.G. Gasanov, S.I. Azi-
mova, R.K. Askerov, A.V. Kurbanov, K.T. Mahmudov, Dyes Pigments 85 (2010)
1–6.
[9] K.T. Mahmudov, M.N. Kopylovich, M.F.C. Guedes da Silva, P.J. Figiel, Y.A.
Karabach, A.J.L. Pombeiro, J. Mol. Catal. A: Chem. 318 (2010) 44–50.
[10] K.T. Mahmudov, A.M. Maharramov, R.A. Aliyeva, I.A. Aliyev, M.N. Kopylovich,
A.J.L. Pombeiro, Anal. Lett. 43 (2010) 2923–2938.
Solvents of different polarities were used to collect experi-
mental spectra, and the same solvents were chosen for the PCM
calculations. It was found that the dipole moment and absorption
spectra are both dependent on solvent type and PCM calculations
may predict those changes, however for most of these compounds
they must be compared with “ordinary” TDDFT to obtain proper
description. Incorporation of the solvent influence model into the
calculations significantly changed the resultant theoretical absorp-
tion spectra. The spectral peak positions were shifted towards
red wavelength in solvent-related calculations with respect to
“solvent-free” TDDFT, and the shift was found to be proportional
to solvent polarity. In the case of acetonitrile (the most polar of the
solvents studied) this shift was as large as 40 nm. Additionally, in
the experimental spectra there were some peaks present in polar
solvents that were absent for non-polar solutions’ spectra. These
differences could be analyzed by comparison with the theoretical
spectra. It was shown that certain excited states (represented by the
above mentioned peaks) had vanishingly low or even zero oscilla-
tion strength when non-polar solvents were used in the calculation
with respect to polar ones. It is thus recommended to employ PCM
model to absorption spectra simulation of azoderivatives in various
solvents.
[11] M.N. Kopylovich, K.T. Mahmudov, M.F.C. Guedes da Silva, M.L. Kuznetsov, P.J.
Figiel, Y.A. Karabach, K.V. Luzyanin, A.J.L. Pombeiro, Inorg. Chem., 50 (2011),
doi:10.1021/ic101516k.
[12] M.N. Kopylovich, K.T. Mahmudov, M.F.C. Guedes da Silva, L.M.D.R.S. Martins,
M.L. Kuznetsov, T.F.S. Silva, A.J.L. Pombeiro, J. Phys. Org. Chem., 24 (2011),
doi:10.1002/poc.1824.
[13] A.M. Maharramov, R.A. Aliyeva, K.T. Mahmudov, A.V. Kurbanov, R.K. Askerov,
Rus. J. Coord. Chem. 35 (2009) 704.
[14] P. Gilli, L. Pretto, V. Bertolasi, G. Gilli, Acc. Chem. Res. 42 (2009) 33–44.
[15] V. Bertolasi, V. Ferretti, P. Gilli, G. Gilli, Y.M. Issa, O.E. Sherif, J. Chem. Soc. Perkin
Trans. 2 (1993) 2223–2228.
[16] V. Bertolasi, P. Gilli, V. Ferretti, G. Gilli, K. Vaughan, New J. Chem. 23 (1999)
1261–1267.
[17] P. Gilli, V. Bertolasi, L. Pretto, A. Lycka, G. Gilli, J. Am. Chem. Soc. 124 (2002)
13554–13567.
[18] V. Bertolasi, L. Pretto, G. Gilli, P. Gilli, Acta Crystallogr. B 62 (2006) 850–863.
[19] P. Gilli, V. Bertolasi, L. Pretto, G. Gilli, J. Mol. Struct. 790 (2006) 40–49.
[20] P. Simunek, V. Bertolasi, V. Machacek, J. Mol. Struct. 642 (2002) 41–51.
[21] J. McVie, D. Alastair, R.S. Sinclair, T.G. Truscott, J. Chem. Soc. Perkin Trans. 2
(1980) 286–290.
[22] F. Huang, Y. Wu, D. Gu, F. Gan, Thin Solid Films 483 (2005) 251–256.
[23] Z. Chen, F. Huang, Y. Wu, D. Gu, F. Gan, Inorg. Chem. Commun. 9 (2006) 21–24.
[24] J. Sokolnicki, J. Legendziewicz, W. Amirkhanov, V. Ovchinnikov, L. Macalik,
Hanuza, J. Spectrochim. Acta A 55 (1999) 349–367.
[25] M.A.N.D.A. Lemos, A.J.L. Pombeiro, J. Organometal. Chem. 332 (1987) C17–C20.
[26] A. Venâncio, M.F.C. Guedes da Silva, L.M.D.R.S. Martins, J.J.R. Fraústo da Silva,
A.J.L. Pombeiro, Organometallics 24 (2005) 4654–4665.
[27] A.J.L. Pombeiro, Eur. J. Inorg. Chem. 11 (2007) 1473–1482.
[28] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato,
X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada,
M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda,
O. Kitao, H. Nakai, T. Vreven, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, M.
Bearpark, J.J. Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, R. Kobayashi, J. Nor-
mand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N.
Rega, J.M. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J. Jaramillo,
R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W.
Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth, P. Salvador,
J.J. Dannenberg, S. Dapprich, A.D. Daniels, O. Farkas, J.B. Foresman, J.V. Ortiz, J.
Cioslowski, D.J. Fox, Gaussian 09, Revision A.02, Gaussian, Inc., Wallingford, CT,
2009.
Acknowledgments
This work has been partially supported by the Foundation for
Science and Technology (FCT), Portugal, and its PPCDT (FEDER
funded) and “Science 2007” programs. M.N.K. and K.T.M. express
gratitude to the FCT for a post-doc fellowship and a working con-
tract. The authors gratefully acknowledge the Portuguese NMR
Network (IST-UTL Center) for the NMR facility. Calculations have
been carried out in Wroclaw Center for Networking and Supercom-
puting (http://www.wcss.wroc.pl), grant No. 135. We would like to
[29] A.R. Allouche, Gabedit is a Free Graphical User Interface for Computational
Chemistry Packages. It is available from http://gabedit.sourceforge.net/.
[30] S. Miertus, E. Scrocco, J. Tomasi, Chem. Phys. 55 (1981) 117–129.
[31] S. Miertus, J. Tomasi, Chem. Phys. 65 (1982) 239–245.
˙
thank Prof. Jerzy Zak and PhD Wojciech Domagała for their valuable
comments on the electrochemical measurements.
[32] A.A. Granovskt, PC GAMESS Version 7.1.E (Firefly), Copyright (c) 1994, Moscow
State University, Moscow, Russia, 2008.
[33] M.W. Schmidt, K.K. Balridge, J.A. Boatz, S.T. Elbert, M.S. Gordon, J.H. Jensen,
S. Koseki, K.A. Matsunaga, S.J. Nguen, T.L. Su, M. Windus, J.A. Dupuis, Mont-
gomery, J. Comput. Chem. 14 (1993) 1347–1363 (PCGAMESS is partially based
on GAMESS (US) ver. 6 June 1999, Iowa State Univ).
[34] F.R. Japp, F. Klingemann, Liebigs Annalen der Chemie 247 (1988) 190–225.
[35] H.C. Yao, P. Resnick, J. Am. Chem. Soc. 84 (1962) 3514–3517.
[36] H.C. Yao, J. Org. Chem. 29 (1964) 2959–2963.
[37] M.N. Kopylovich, K.T. Mahmudov, A.J.L. Pombeiro, J. Hazard. Mater. 186 (2011),
doi:10.1016/j.jhazmat.2010.11.119.
[38] J. Marten, W. Seichter, E. Weber, Zeitschrift für anorganische und allgemeine
Chemie 631 (2005) 869–877.
[39] J. Marten, W. Seichter, E. Weber, U. Bohme, J. Phys. Org. Chem. 20 (2007)
716–731.
[40] C. Bustos, C. Sanchez, R. Martınez, R. Ugarte, E. Schott, C.D. Mac-Leod, M.T.
Garland, L. Espinoza, Dyes Pigments 74 (2007) 615–621.
[41] J. Marten, W. Seichter, E. Weber, U. Bohme, CrystEngComm 10 (2008) 541–547.
[42] E. Weber, J. Marten, W. Seichter, J. Coord. Chem. 62 (2009) 3401–3410.
[43] S. Trasatti, Pure Appl. Chem. 58 (1986) 955–966.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.saa.2010.12.080.
References
[1] M. Czerwinski, J. Bieleninik, J. Napieralski, I.V. Kityk, J.R.I. Kasperczyk Mervin-
skii, Eur. Polym. J. 33 (1997) 1441–1447.
[2] M.G. Brik, E. Gondek, T. Uchacz, P. Szlachcic, P. Jarosz, K.J. Plucinski, Chem. Phys.
370 (2010) 194–200.
[3] D.R. Kanis, M. Ratner, T.J. Marks, Chem. Rev. 94 (1994) 193–201.
[4] P. Calaminici, K. Jug, A.M. Koester, C. Arbez-Gindre, C.G. Screttas, J. Comput.
Chem. 23 (2002) 291–297.
[5] J.L. Brédas, D. Beljonne, V. Coropceanu, J. Cornil, Chem. Rev. 104 (2004)
4971–5003.
[6] S.A. Locknar, L.A. Peteanu, Z.G. Shuai, J. Phys. Chem. A 103 (1999) 2184–
2196.
[44] V.V. Pavlishchuk, A.W. Addison, Inorg. Chim. Acta 298 (2000) 97–102.