Physical optical properties and crystal structures of organic 5-sulfosalicylates - Theoretical and experimental study

Article abstract of DOI:10.1016/j.molstruc.2011.06.043

A discussion on the possible application of the organic 5-sulfosalicylates as organic materials with tunable optical and non-linear-optical (NLO) properties is performed on the basis of the experimental crystallographic and spectroscopic methods such as s

Full text of DOI:10.1016/j.molstruc.2011.06.043

Journal of Molecular Structure 1003 (2011) 1–9
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Physical optical properties and crystal structures of organic
5-sulfosalicylates – Theoretical and experimental study
⇑
⇑
Bojidarka B. Ivanova , Michael Spiteller
Institut für Umweltforschung, Universität Dortmund, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 April 2011
Received in revised form 27 June 2011
Accepted 28 June 2011
Available online 13 July 2011
A discussion on the possible application of the organic 5-sulfosalicylates as organic materials with tun-
able optical and non-linear-optical (NLO) properties is performed on the basis of the experimental crys-
tallographic and spectroscopic methods such as single crystal X-ray diffraction, electronic absorption,
diffuse reflectance and fluorescence spectroscopy in condense phase, conventional and linear-polarized
IR- and Raman spectroscopy in solid-state. The model systems 5-sulfosalicylic acid dihydrate (1),
4-aminobenzamidinium bis(5-sulfosalicylicilate) monohydrate (2) and 5-sulfosalicylicilate salt of glycin-
amide (3), comparing with the as well as theoretical quantum chemical calculations of the systems
neutral 5-sulfosalicylic acid (I), its mono-(Ia) and dianion (Ib), respectively.
Keywords:
Organic 5-sulfosalicylates
Crystals
Optical and NLO properties
Quantum chemistry
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
as single crystal X-ray diffraction, UV–VIS–NIS, diffuse reflectance
and fluorescence spectroscopy in solid-state, conventional and lin-
The self-assembly of the multifunctional organic acids in the
crystals as well as their coordination ability towards the metal ions
is currently of great importance, due to their usage in the crystal
engineering and materials research for design and synthesis of or-
ganic and metal–organic materials with tunable optical and non-
linear optical (NLO) properties [1–14]. From the coordination
chemistry point of view the 5-sulfosalicylic acid (5SSA, Scheme
1(I)) is especially attractive ligand, possessing three potential coor-
dination groups, i.e. AOH, ACOOH and ASO3H, thus coordination
to the metal ions in a variety of modes [1–4]. 5SSA has been also
intensively study due to the possibility to formation of the pro-
ton-transfer organic salts, mainly with N-heterocyclic basis with
tunable optical properties [15–18]. During all of these studies has
been found that in parallel with the excellent coordination and/
or protonation ability the obtained crystals of 5SSA are character-
ized with the transparency within large spectroscopic region, good
optical qualities, and reasonable rate of crystal growth as well as
high thermal stability [1]. However, still remain the question is it
possible to be use 5SSA as NLO-phore, such for example squaric
acid and its derivatives [19–22]? Herein we are reported the theo-
retical and experimental study of the three model systems (1)–(3),
depicted in Scheme 1 as well as corresponding neutral form of the
5SSA (I) and its mono-(Ia) and di-(Ib) anions. The ab initio and DFT
quantum chemical calculations as well as physical methods such
ear-polarized IR- and Raman spectroscopy in solid-state are used.
2. Experimental
2.1. Synthesis
The 5-sulfosalicylic acid dihydrate (1) was obtained by the re-
crystallization of 5-sulfosalicylic acid monohydrate (Sigma–Al-
drich) in water under stirring for 30 min at 150 °C. The obtained
after a week colourless crystals were filtered off, washed with
CH3OH and dried on P2O5 at 298 K. Yield 98%. Found (1): C, 33.07;
H, 3.93; calcd. for C7H10O8S: C, 33.07; H, 3.96%; Compounds 4-ami-
nobenzamidinium bis(5-sulfosalicylicilate) monohydrate (2) and 5-
sulfosalicylicilate salt of glycinamide (3) were obtained by mixing
of 4-aminobenzamidin (0.1352 g) or glycinamide (0.0741 g) with
0.4391 g or 0.2181 g 5-sulfosalicylicilic acid in 20 ml solvent mix-
ture methanol:water 1:1. The resulting colourless crystals were fil-
tered off, washed with CH3OH and dried on P2O5 at 298 K. Yield 95
(2) and 87 (3)%, respectively. Found (2): C, 42.33; H, 4.30; calcd. for
C21H25O13N3S2: C, 42.64; H, 4.26%; Found (3): C, 37.25; H, 3.49;
calcd. for C9H10O7N2S: C, 37.24; H, 3.47%.
2.2. Physical methods
The X-ray diffraction intensities were measured on a Bruker
⇑
Corresponding authors. Tel.: +49 231 755 4080; fax: +49 231 755 4089.
E-mail addresses: B.Ivanova@infu.uni-dortmund.de (B.B. Ivanova), Spiteller@-
Smart X2S diffractometer, using micro source Mo K
a radiation
infu.tu-dortmund.de (M. Spiteller).
and employing the scan mode. The data were corrected for
x
0022-2860/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2011.06.043

2
B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
OH
OH
OH
COOH
COOH
COO
SO3H
SO3
SO3
(I)
(Ia)
(Ib)
H2N
NH2
OH
OH
OH
COOH
COOH
COOH
O
2
x
H2O
x
x
H3N
x
2H2O
NH2
SO3
SO3
SO3H
NH3
(1)
(2)
(3)
Scheme 1. Chemical diagram of 5-sulfosalicylic acid (I), its mono- (Ia) and dianion (Ib) as well as the compounds studied 5-sulfosalicylic acid dihydrate (1),
4-aminobenzamidinium bis(5-sulfosalicylicilate) monohydrate (2) and 5-sulfosalicylicilate salt of glycinamide (3).
Lorentz and Polarization effects. An absorption correction based on
multiple scanned reflections [23–25]. The crystal structures were
solved by direct methods using SHELXS-97 [23–25]. The crystal
structures were refined by full-matrix least-squares refinement
against F2 [26–28]. Anisotropic displacement parameters were
introduced for all non-hydrogen atoms. The hydrogen atoms at-
tached to carbon were placed at calculated positions and refined
allowing them to ride on the parent carbon atom. The hydrogen
atoms bound to nitrogen and the oxygen were constrained to the
positions which were confirmed from the difference map and re-
fined with the appropriate riding model, which the exception of
the amino and water hydrogen atoms. The experimental refine-
ment data are collected in Table 1.
Electrospray ionization (ESI) mass spectrometry. A triple quadruple
mass spectrometer (TSQ 7000 Thermo Electron, Dreieich, Germany)
equipped with an ESI 2 source was used and operated at the follow-
ing conditions: capillary temperature 180 °C; sheath gas 60 psi,
corona 4.5 lA and spray voltage 4.5 kV. Sample was dissolved in
acetonitrile (1 mg ml–1) and was injected in the ion source by an
autosampler (Surveyor) with a flow of pure acetonitrile (0.2 ml
min–1). Data processing was performed by Excalibur 1.4 software.
Non-polarized solid-state IR spectra were recorded using the KBr
disk technique. The oriented samples were obtained as a suspension
in a nematic liquid crystal (ZLI 1695, Merck). The UV–VIS–NIR and
fluorescence spectra were recorded on Tecan Safire Absorbance/
Fluorescence XFluor 4 V 4.40 spectrophotometer. Solid-state UV–
Vis spectra were measured on a PerkinElmer Lambda 750 in reflec-
tance mode. The reflection spectra were automatically converted
to absorbance spectra using Kubelka–Munk theory.
The IR-spectra were measured on a Thermo Nicolet 6700 FTIR
,
spectrometer (4000–400 cmꢀ1 2 cmꢀ1 resolution, 200 scans)
equipped with a Specac wire-grid polarizer. Solid-state Raman spec-
tra were recorded on Nicolet NXR 9610 FT-Raman spectrometer.
HPLC-MS/MS measurements were made following a reported
procedure by Threlfall et al.1s using TSQ 7000 instrument (Thermo
Electron Corporation). Two mobile phase compositions were used:
(A) 0.1% v/v aqueous HCOOH and (B) 0.1% v/v HCOOH in CH3CN.
2.3. Computational details
Quantum chemical calculations are performed with GAUSSIAN 98
and Dalton 2.0 program packages [29,30]. The geometries of the
studied species I, Ia and Ib were optimized at two levels of theory:
second-order Moller–Pleset perturbation theory (MP2) and density
functional theory (DFT) using the 6-31++G(d,p) basis set. The DFT
method employed is B3LYP, which combines Backe’s three-param-
eter non-local exchange function with the correlation function of
Lee, Yang and Parr. Molecular geometries of the studied species
were fully optimized by the force gradient method using Bernys’
algorithm. For every structure the stationary points found on the
molecule potential energy hypersurfaces were characterized using
standard analytical harmonic vibrational analysis. The absence of
the imaginary frequencies, as well as of negative eigenvalues of
the second-derivative matrix, confirmed that the stationary points
correspond to minima of the potential energy hypersurfaces. The
calculation of vibrational frequencies and infrared intensities were
checked to establish which kind of performed calculations agree
best with the experimental data. The UV spectra in the gas phase
and water are obtained by CIS/6-31++G(d,p) and TDDFT calcula-
tions at same basis set [31]. For all the species considered we have
calculated geometries at the second order of Møller-Plesset pertur-
bation theory [32] (MP2) using the polarized SBK basis set. [33] The
effect of geometry on the visible–UV energies was fairly small. In
addition, polarized SBK MP2 is an efficient, medium level corre-
lated method which normally gives very accurate geometries at
modest computational cost. For the calculation of the visible–UV
energies we used both all-electron 6-311+G(2d,p) bases [34] and
Table 1
Crystallographic and refinement data for compounds (1)–(3).
(1)
(2)
(3)
Empirical
formula
Mr
Crystal size,
mm
Crystal
system
Space group
T (K)
k (Å)
a (Å)
b (Å)
c (Å)
C7H6O8S
C21H21N3O13S2
C9H12N2O7S
250.18
587.53
292.27
0.50 ꢁ 0.44 ꢁ 0.32 0.23 ꢁ 0.21 ꢁ 0.17 0.40 ꢁ 0.30 ꢁ 0.22
Triclinic
Monoclinic
Triclinic
ꢀ
ꢀ
P21/n
P1
P1
200(2)
199(2)
0.71073
7.1585(11)
9.3512(15)
35.924(6)
90
90.216(5)
90
2404.8(7)
4
199(2)
0.71073
6.925(2)
6.967(2)
11.480(3)
83.184(8)
74.285(8)
70.771(8)
503.2(2)
2
0.71073
8.128(2)
8.591(3)
9.713(3)
64.322(6)
86.766(9)
81.477(9)
604.5(3)
2
a
(°)
b (°)
(°)
c
V (°)
Z
l
(mmꢀ1
)
200(2)
1.651
0.299
1.623
0.301
1.606
qcalc
(mg mꢀ3
)
2h (°)
25.15
1.066
25.17
0.999
22.95
1.409
Goodness-of-
fit on F2
R1 (I > 2
r
(I))
0.0842
0.0414
0.0513

B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
3
the polarized SBK bases and employed both HF and DFT type meth-
ods. In a few cases we also have also utilized the large ‘‘correlation
consistent’’ basis sets from Dunning’s group [35] at the aug-cc-
pVDZ and aug-cc-pVTZ [35]. The DFT studies have been done
mainly with the hybrid B3LYP potential. [36] Basically, CIS de-
scribes the excited state wave function at a level comparable to
Hartree–Fock, using single excitations from the HF determinant.
The TD HF method, includes some double excitations, giving a
slightly correlated description of both ground and excited states.
To describe the species in aqueous solution we use both an explicit
super molecule and micro hydration approach, in which several
water molecules are coordinated to the solute at the optimized
geometry of the super molecule, and a polarizable continuum ap-
proach. The geometries of all the super molecules in the present
study were obtained by a similar approach, but utilizing the polar-
ized SBK basis set at the MP2 level. The geometries have been ver-
ified to be local energy minima by frequency analysis, but are not
necessarily the global minima. These species are in fact just simple
approximations to the real hydrated species. We have not system-
atically studied the effect of varying the number of water mole-
cules in the super molecule, although we have employed a very
large super molecule. A ‘‘mixed’’ approach, employing both micro
hydration and a polarizable continuum was also used [37]. We
have utilized primarily the COSMO or CPCM version [38] of the
polarizable continuum model, although we have also tested the
computationally less stable is density polarized continuum model.
[39] The COSMO solvation approach has been applied both to bare
anionic solutes and to the micro hydrated species. For the very
largest species considered, we have employed the ONIOM method,
[40] in which different parts of the super molecule can be treated
at different levels of accuracy, using different basis sets or even dif-
ferent quantum methods. We employed the 6-311+G(2d,p) basis
for the S atoms and the 6-31G⁄ basis for the surrounding water
molecules in the CIS ONIOM calculations. We are performed as
well the calculations at MO5-2X, and MO6-2X XC functionals
[41–43]. As far as the DFT, at B3LYP level of theory, has some seri-
ous shortcomings, it is inaccurate for interactions dominated by
medium-range correlation energy, like our systems. For so-called
M06-class (and, earlier, M05-class) functionals, has been enforced
some fundamental exact constraints such as the uniform-electron–
gas limit and the absence of self-correlation energy. The M06-class
functionals depend on spin-up and spin-down electron densities,
spin density gradients, spin kinetic energy densities, and, for
nonlocal functionals, Hartree–Fock exchange. Our data show that
M06-2X, a hybrid meta functional, is a functional with good accu-
racy for medium-range correlation energy, and barrier heights.
M06-2X, has excellent predicts accurate valence and Rydberg elec-
tronic excitation energies, and is an excellent functional for
aromaticꢀaromatic stacking interactions. The optical properties
of the crystals were calculated at the above levels of theory, using
the crystallographic data set as input parameters according the
approaches, demonstrated in [20,21,44–46], utilizing the triple-f
quality TZVP, triple-f plus double polarization TZ2P, Los Alamos
National Laboratory’s
2 double-f as well as quasirelativistic
effective core pseudopotentials from Stuttgart-Dresden. The large
‘‘correlation consistent’’ basis sets [47–50] aug-cc-pVDZ and aug-
cc-pVTZ (augmented correlation-consistent polarized valence dou-
ble and triple zeta levels) are also applied in few cases.
2.4. Statistical analysis
The experimental and theoretical spectroscopic patterns were
processed by R4Cal OpenOffice STATISTICs for Windows 7 [51] pro-
gram package. Baseline corrections and curve-fitting procedures were
applied. The baseline was calculated using the standard linear
equation. The curve-fitting nonlinear procedure was applied. In
the case of the Levenberg–Marquardt method, the merit equation
used is v2 the equation. The final solution is found when a mini-
mum in the reduced v2 equation is reached. It is a statistical mea-
sure of ‘‘goodness-of-fit’’, inversely proportional to the known
variance of the data set. The statistical significance of each regres-
sion coefficient was checked by the use of t-test (calculation of the
number of significance using data from the experimental error,
usually higher than 0.100). The model fit was determined by F-test
[20,21,44,45].
3. Results and discussion
3.1. Crystal structures of (1)–(3)
The 5-sulfosalicylic acid dihydrate (1), crystallizes in the triclinic
P1 space group (Fig. S1). The 5SSA molecules form infinite layers
ꢀ
through the intermolecular interaction OHꢂ ꢂ ꢂOS (2.614, 3.033 Å)
(Fig. 1). The interlayer space is occupied by the solvent water
molecules taking part in the hydrogen bond networks themselves
Fig. 1. Unit cell and hydrogen bonding networks in the crystals (1)–(3); photographs of the crystals without and under irradiation at kmax = 365 nm.

4
B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
I
Ia
Ib
(
Ia
)
(I
)
Ib)
(
νOH
Scheme 2. Optimized geometries of the 5SSA (I), its mono-(Ia) and dianion (Ib).
and with the 5SSA molecules as well (2.407, 2.732, 2.600 Å). Similar
to the theoretically obtained stable conformer of 5SSA (Scheme 2),
an intramolecular OHꢂ ꢂ ꢂO bond of 2.628 Å is experimentally found
(Fig. 1). The ASO3H fragment is with a distorted pyramidal sub-
structure, characterizing with SAO bond lengths of 1.446, 1.444,
1.458 Å. The obtained structural parameters of (1) correlated well
with those of corresponding 5-sulfosalicylic acid penta- and trihy-
drate [52–54]. Compound (2), i.e. 4-aminobenzamidinium bis(5-
sulfosalicylicilate) monohydrate crystallizes in the monoclinic
P21/n space group (Fig. S1). The 4-aminobenzamidinium dication
and the 5SSA anions as well as the solvent molecule for a 3D network
(Fig. 1) by the following intermolecular hydrogen bonds, N+H3ꢂ ꢂ ꢂO
(2.806, 2.744, 2.976, 2.977 Å), N+H2ꢂ ꢂ ꢂO (2.743, 3.043, 2.986 Å) and
OHꢂ ꢂ ꢂO (2.990, 2.922 Å). The ASOꢀ3 sub-fragment is characterized
with S-O bond lengths within 1.441–1.459 Å. The 5-sulfosalicylici-
o.p. (v4)
Scheme 3. Visualization of the selected transition moments of the I, Ia and Ib,
respectively.
between the OH-group and the ACOOH one with bond lengths
within 2.580–2.613 Å, depending of the used level of theoretical
approximation. The dianionic form Ib is characterized with a dis-
position of the -OH proton between both O-centres of the hydro-
xyl- and COOꢀ-groups. The deprotonation of the ASO3H group in
Ia and Ib result to the observation of he pyramidal sub-structure
of the ASOꢀ3 group with bond lengths within 2.512–2.620 Å, thus
correlation well with the experimental crystallographic data. The
Ia is characterized with higher values of dipole, quadrupole (XX),
octapole (XXX) and hexadecapole (XXXX) moments (Table 2).
The XX and XXXX values of Ia and Ib are comparable, in contrast
to the values of XXX of Ia, value about 125 times higher than the
value of Ib, respectively. The calculated btot values of the I, Ia and
Ib are 95.6, 139.7 and 13.3 (ꢁ10ꢀ30 cm5 esuꢀ1) respectively, using
the equation ||b|| = ðbx2 þ by2 þ b2z Þ1=2. The values of I and Ia are with-
in 1.4 – 4.2 higher than urea, using as standard [55], thus illustrat-
ing the potential for the application of co-crystals of SS5 as well as
ionic crystals of the monoanion of the acid as NLO materials [55–
60]. The obtained values of btot for the crystals of (1)–(3) are
191.7, 558.6 and 349.3 (ꢁ10ꢀ30 cm5 esuꢀ1), or values about 5.4–
8.4 times higher than urea. It must be note, that obtained higher
values of the btot in the crystals, comparing with the corresponding
values of the isolated molecular species, arise the question for the
ꢀ
late salt of glycinamide (3) crystallizes in also in triclinic P1 space
group (Fig. S1). The cations form dimers through NHꢂ ꢂ ꢂO bond
(2.873 Å). The cations and anions participate in the intermolecular
N+H3ꢂ ꢂ ꢂO interactions with bond lengths of 2.764, 2.886, 2.933,
2.886 Å (Fig. 1). The intramolecular OHꢂ ꢂ ꢂO bond is characterized
with the bond length of 2.625 Å.
3.2. Theoretical calculations
As a strong triprotic acid with proton-donation ASO3H, ACOOH
and AOH groups, characterizing with the K1 > 0.1, K2 = 1.4 ꢁ 10ꢀ3
and K3 = 4 ꢁ 10ꢀ14, the quantum chemical calculations of 5SSA
are performed on neutral molecule (I), and its anions Ia, Ib
(Scheme 1), stabilized by the interaction with strong bases [54].
The optimized molecular geometries are depicted in Scheme 2.
Such as the crystallographic data of (1)–(3), the 5SSA both in I or
Ia is characterized with the strong intramolecular OHꢂ ꢂ ꢂO bond
Table 2
Theoretical calculated values of the dipole, quadrupole, octapole and hexadecapole moments of I, Ia and Ib, respectively.
Dipole moment [D]
(I)
3.2
(Ia)
(Ib)
12.3
5.9
Quadrupole moment [D-Å]
XX
YY
ZZ
XY
XZ
YZ
(I)
(Ia)
(Ib)
ꢀ87.7
ꢀ146.4
ꢀ196.6
ꢀ80.8
ꢀ93.1
ꢀ119.5
ꢀ88.7
ꢀ98.7
ꢀ100.5
9.0
9.6
0.2
0.2
ꢀ2.0
ꢀ14.5
0.0
4.6
ꢀ0.1
Octapole moment [D-Å2]
XXX
9.8
125.0
0.9
YYY
ZZZ
3.1
XYY
XXY
XXZ
42.6
ꢀ1.5
ꢀ1.9
XZZ
0.4
34.9
33.5
YZZ
ꢀ9.1
ꢀ2.5
1.2
YYZ
5.3
6.4
6.9
XYZ
(I)
(Ia)
(Ib)
ꢀ18.8
ꢀ15.8
30.3
ꢀ31.4
ꢀ50.2
ꢀ29.6
33.9
ꢀ6.3
ꢀ2.7
ꢀ2.6
ꢀ7.5
36.3
ꢀ7.7
ꢀ30.9
Hexadecapole moment [D-Å3]
XXXX
YYYY
ZZZZ
XXXY
32.3
XXXZ
186.7
ꢀ1.8
ꢀ1.8
YYYX
152.7
YYYZ
ꢀ7.8
ꢀ8.5
ꢀ8.3
ZZZX
17.6
22.7
23.5
ZZZY
ꢀ3.2
3.2
XXYY
XXZZ
YYZZ
XXYZ
ꢀ20.2
15.2
YYXZ
17.9
ZZXY
ꢀ4.5
(I)
(Ia)
(Ib)
ꢀ2907.9
ꢀ3837.3
ꢀ4571.1
ꢀ810.2
ꢀ922.4
ꢀ1102.8
ꢀ203.1
ꢀ236.4
ꢀ240.7
ꢀ598.0
ꢀ711.7
ꢀ974.2
ꢀ492.2
ꢀ646.9
ꢀ672.0
ꢀ196.3
ꢀ213.2
ꢀ213.0
ꢀ79.8
ꢀ170.6
ꢀ18.6
ꢀ14.7
ꢀ21.7
117.5
30.944
3.2
12.5
ꢀ19.2

B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
5
Fig. 2. Solid-state IR-spectra of (1) and (3) within 4000–400 cmꢀ1 IR-region.
coherent character of the discussed parameter, as molecular char-
acteristic within the frame of the molecular ensemble in the crys-
tals, depending of the self-assembly. As could see, the lower value
is obtained for (3) calculated according the crystallographic 3D
networks, formed by the intermolecular interactions, including
hydrogen bonding as well as electrostatic forces. In contrast the
Fig. 3. Solid-state Raman spectra of the crystals of (1)–(3) within 200–30 cmꢀ1; curve-fitted spectroscopic patterns, using preliminary baseline correction method, by
non-linear multipeak Lorenzian–Gaussian function at ratio 1:1; A-total area under the curve from the baseline centre of the peak; w2 ‘‘sigma’’, approximately 0.441 the
FWHM; w/2 – is the standard deviation, respectively.

6
B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
calculated layers (or chains) self-assembly in (1) and (2), result to
the higher values of the btot
strongly of the space system, and number of the molecules per unit
cell [71–74].
.
The calculated IR-spectra of the studied species (Scheme 2) are
depicted in Fig. S2. The IR-band at 3354 cmꢀ1 (I), 3318 cmꢀ1 (Ia)
and at 2164 cmꢀ1 (Ib) belongs to the mOH stretching vibration of
the intramolecular hydrogen bonded OH-group (Scheme 3). The
IR-bands about 715, 660 and 570 cmꢀ1 correspond to the out-
of-plane (o.p.) vibrations of the 5SSA skeleton. The calculated
Raman spectra within 200–30 cmꢀ1 are summarized in the Table
4. The obtained theoretical patterns are performed studying the
molecular self-assembly both in the unit cell as well as in the
asymmetric units in the crystals. For the (1) and (3), where the
Z = 2 the calculations are carried out, by the unit cell content. The
crystal of (2), with Z = 4 is calculated, using the different self-assem-
blies of the interacted species of dimers, as well as the observed tet-
ramer, respectively.
3.4. Electronic absorption, diffuse reflectance and fluorescence
properties
The electronic transmission spectra of the obtained compounds
are characterized with the bands about 200, 230 and 290 nm with
the em values about 16,700, 15,000 and 4000 l molꢀ1 cmꢀ1 of the
5SSA and its anion Ia (Fig. S4). Similar to the corresponding IR-char-
acteristics, the deprotonation of the ASO3H effect insignificant the
corresponding K-, B- of the benzene fragment and n ? p⁄ transition
of the C@O one. The data correlated well with the theoretically
predicted values (Table 3) at different level of approximation. As
can be see the MO6-2X XC and MO5-2X [26–28] described in a good
agreement the electronic transitions in these systems, such as the
B3LYP/6-31++G(2p,2d) level. Moreover the predicted higher f values
of the studied systems by the first two functional correlate better to
the experimental em ones. The obtained theoretically HOMO–LUMO
gaps (SchemeS1) of the SS5 species, are characterizedwith the open-
shell singlet ground state as well as the stabilization and charge
redistribution. The compounds studied are characterized with the
transparency within whole 290–1100 nm region. The optical prop-
erties in solid-state (Fig. 4), both diffuse reflectance (DF) as well as
fluorescence, show emissions of light at kex 365 nm, Fig. 1, within
3.3. Vibrational properties
The solid-state IR-spectra of the neutral I type 5SSA in (1) and Ia
form in (2) and (3), respectively, are characterized with the low-
intensive IR-bands at 1610, 1578 cmꢀ1 of the in-plane (i.p.) vibra-
tions of the 5SSA skeleton (theoretical values of 1607, 1575 cmꢀ1),
which are weak effect of the deprotonation of the ASO3H group in
the salts. Same is valid for the corresponding o.p. v4 and v11 vibra-
tions about at 715, 660 and 575 cmꢀ1 (Fig. 2). The typical for the
450–550 nm, believed to enhance to
p ?
p⁄ transitions in the SS5.
asymmetric sub-fragment –SO3H IR-bands within 1415 85 cmꢀ1
It is interesting to discuss the observation of the low intensive bands
as
ðm
Þ and 1195 60 cmꢀ1
(
msSO2). The mSAO stretching vibration is
SO2
observed within region 795 35 cmꢀ1. The deprotonation of the dis-
Table 4
cussed group in the salts (2) and (3) leads to a higher local symmetry
and a low-frequency shifting of the mSAO vibrations of the XY3 system
Solid-state Raman frequencies and assignment of the studied compounds within 200–
30 cmꢀ1 [cmꢀ1 (THz)].
; m
(ASOꢀ3 ). The IR-spectra of both the salts (2) and (3) are character-
ized additionally with the corresponding characteristic IR-bands
of the counterions, such for example the typical for the amide
group vibrations in the glycinamide (3333, 3249, 1707 cmꢀ1).
The solid-state Raman spectra of the studied crystals within
4000–200 cmꢀ1 are characterized with underlined fluorescence
gap (Fig. S3), difficult the detail assignment of corresponding fre-
quencies within the mid-IR region. For the aim of the THz-technol-
ogies, for determination of the chemical substances within the
THz-region, according the recent studies in the field [61–67], the
region of 6.0–0.9 THz show the well define and intensive modes
(Table 4), belonging to the H-bonding deformations, lattice and
skeletal vibrations, as well as coupling modes, respectively. The
specific interactions in the crystals of (1)–(3) result to the strong
individual patterns within the 200–30 cmꢀ1, region, allowing their
determination in the crystalline state (Fig. 3). The excitation about
(1)
(2)
(3)
Theor. Exp.
Theor. Exp.
Theor. Exp.
H-bonding deformations
OHꢂ ꢂ ꢂOS, OHꢂ ꢂ ꢂO,
165
166
154
150
N+H3ꢂ ꢂ ꢂO, N+H2ꢂ ꢂ ꢂO
(4.95) (4.98) (4.62) (4.5)
130
(3.9)
119
132
(3.96)
119
110
(3.3)
80
111
120
118
(3.54)
(3.33) (3.57) (3.57) (3.6)
Skeletal modes
80
(2.4)
80
(2.4)
80
(2.4)
(2.4)
71
71
(2.13) (2.13)
50
(1.5)
55
(1.65)/
46
Torsion of entire side
chain about the
aromatic system
37
38
37
38
37
36
(1.11) (1.14) (1.11) (1.14) (1.11) (1.08)
a
70 cmꢀ1 (Table 4), assigned to the CC N deformations as well as
those to the with underlined LO-TO splitting effect, depending
Table 3
Theoretical and experimental (in water) absorption UV-bands of I, Ia, Ib, (1), (2) and (3), respectively.
k (nm) (f)
B3LYP/6-31++G(2p,2d)
MO5-2X
CAM-B3PW91
(I)
(Ia)
(Ib)
199 (0.6241)
205 (0.5788)
205 (0.6721)
MO6-2X XC
202 (0.8962)
200 (0.8762)
205 (0.8999)
225 (0.4761)
220 (0.6991)
220 (0.8453)
288 (0.2221)
291 (0.1189)
290 (0.2044)
200 (0.8561)
210 (0.7781)
210 (0.8618)
229 (0.8801)
230(0.8410)
230 (0.8971)
CAM-B3LYP
215 (0.4009)
220 (0.4500)
220 (0.4671)
290 (0.2268)
290 (0.2671)
290 (0.2689)
200 (0.6682)
205 (0.6066)
205 (0.5681)
220 (0.5001)
220 (0.5301)
220 (0.4033)
290 (0.1117)
295 (0.1261)
295 (0.1171)
(I)
(Ia)
(Ib)
230 (0.8987)
230 (0.7952)
230 (0.7988)
292 (0.2355)
290 (0.2341)
290 (0.2344)
210 (0.4789)
190 (0.4567)
190 (0.4671)
285 (0.4461)
285 (0.4464)
285 (0.4571)
Experimental electronic spectra
(1)
(2)
(3)
200
205
203
228
230
229
291
290
292

B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
7
Fig. 4. Solid-state diffuse reflectance (DS) and fluorescence (F) spectra in solid-state; curve-fitted spectroscopic patterns, using preliminary baseline correction method, by
non-linear multipeak Gaussian function at ratio 1:1; A-total area under the curve from the baseline centre of the peak; w2 ‘‘sigma’’, approximately 0.863 the FWHM; w/2 – is
the standard deviation, respectively [68–70].
HOMO
LUMO
HOMO
LUMO
HOMO
LUMO
(1)
(2)
(3)
Ecal [eV]
4.05
308.6
0.0031
76 %
3.77
330.6
0.0077
81 %
4.05
306.7
0.0104
84 %
λ
f
cal [nm]
State
Scheme 4. Theoretical Results on Energy and Frontier Orbitals, presented as HOMO and LUMO gaps of the crystals (1)-(3) at CAM-B3PW91/6-31+G(d,p) level of theoretical
approximation.
about 305 nm (1) and 315/330 nm ((2) and (3), respectively (Fig. 4)
in the DS spectra. The origin of those bands needs further discussion.
The correlation between the crystallographic data and electronic
spectra shows different structural motifs, thus excluding the possi-
bility for the origin of the observed transitions within the frame of
isolated molecule. The quantum chemical calculations of the optical
properties of the studied crystals, using the unit cell contents as well
as the two neighbouring unit cells are also performed. Interesting
feature lies in the frontier orbital analysis, proposing an interlayer
CT effect in the crystals. The obtained HOMO–LUMO MO gaps
(Scheme 4) are localized in the SS5 in the frame of the different lay-
ers. The transition was calculated to be within 4.05–3.77 eV, respec-
tively, the results of which are well-correlated with the bands within
308–330 nm in the diffuse reflectance spectra. The frontier orbital
analyses reveal that the
p-electron density in the excited-state is
mainly delocalized at the SS5 as chromophore moiety, in (1) and
(3), in sharp contrast, to (2), where it is largely spread around the cat-
ionic moiety. So, the observed results show that we could principally

8
B.B. Ivanova, M. Spiteller / Journal of Molecular Structure 1003 (2011) 1–9
assigned the observed solid-state phenomena as a result of the
interlayers CT-states. On the other side for the solid-state spectra
the corresponding CT bands both in the diffuse reflectance as well
as the fluorescence spectra are multicomponent splitted. The ob-
served relatively low value of the r2 of the non-linear curve-fitting
method, with the apply Gaussian function of 97.9% (Fig. 4) is a result
of the obtained low S/N value within 350–400 cmꢀ1, respectively
[20,21].
spectra of the crystals (Figure S2); UV–VIS–NIS transmission spectra
in solution within 190–1100 nm (Figure S3). Supplementary data
associated with this article can be found, in the online version, at
doi:10.1016/j.molstruc.2011.06.043.
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The design of the novel materials with NLO application and
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Appendix A. Supplementary data
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre, CCDC
776415–776417 Copies of this information may be obtained from
the Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (Fax:
+44 1223 336 033; e-mail: deposit@ccdc.cam.ac.uk or http://
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