Studies on synthesis, structural, luminescent and thermal properties of a new non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate

Article abstract of DOI:10.1016/j.physb.2016.12.009

A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors which stabilize the structure of the crystal. The compound crystallizes in triclinic system with space group P-1. Elemental analysis, thermal analysis, UV–Vis–NIR, FT-IR and NMR spectral analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of the title crystal were analyzed to recommend the material for optical applications. Z-scan was used to measure the effective third-order nonlinear optical susceptibility and nonlinear refractive index. The crystal structure was determined using single crystal XRD method and the structure was optimized using Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set. This hydrogen bond interactions led to the increase in first-order hyperpolarizability of ATHTP and was 30 times greater than that of urea. Hirshfeld analyses surface analysis was carried out to explore intermolecular interactions in the crystalline state.

Full text of DOI:10.1016/j.physb.2016.12.009

Author’s Accepted Manuscript
Studies on synthesis, structural, luminescent and
thermal properties of a new non-linear optical
crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-
2,4,6-trinitrophenolate
P. Dhamodharan, K. Sathya, M. Dhandapani
www.elsevier.com/locate/physb
PII:
S0921-4526(16)30577-4
http://dx.doi.org/10.1016/j.physb.2016.12.009
PHYSB309750
DOI:
Reference:
To appear in:
Physica B: Physics of Condensed Matter
Received date: 30 September 2016
Accepted date: 6 December 2016
Cite this article as: P. Dhamodharan, K. Sathya and M. Dhandapani, Studies on
synthesis, structural, luminescent and thermal properties of a new non-linea
optical
crystal:
4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6
trinitrophenolate, Physica B: Physics of Condensed Matter
http://dx.doi.org/10.1016/j.physb.2016.12.009
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Studies on synthesis, structural, luminescent and thermal properties of a new
non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-
trinitrophenolate
P. Dhamodharan, K. Sathya and M. Dhandapani*
Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science,
Coimbatore-641 020, Tamil Nadu, India.
*Corresponding author’s ; Phone: +91 94420 01232. srmvdhandapani@gmail.com
Abstract:
A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-
1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors
which stabilize the structure of the crystal. The compound crystallizes in triclinic system with
space group P-1. Elemental analysis, Thermal analysis, UV-Vis-NIR, FT-IR and NMR spectral
analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of
the title crystal were analyzed to recommend the material for optical useful applications. Z-scan
was used to measure the effective third-order nonlinear optical susceptibility and nonlinear
refractive index. The crystal structure was exploited using single crystal XRD and the obtained
structure was optimized using Gaussian 09 program B3LYP/6-311++G(d,p) level of basis set.
This hydrogen bond interactions leads to the increase in hyperpolarizability of ATHTP and was
30 times greater than that of urea. Hirshfeld analyses were carried out to explore covalent and
non covalent interactions.
Keywords:
Single crystal XRD, Phosphorescence, Hydrogen bonding, Hirshfeld, Hyperpolarizability.

1. Introduction
Supramolecular architectures assembled from numerous delicate non-covalent
interactions like hydrogen bonds, π ˗ π* stacking and electrostatic interactions etc., have large
interest in their wide applications in life and materials science [1, 2]. Intermolecular interactions
are really exciting to explore in any molecular material. An in-depth analysis of these
interactions becomes handy when the material is in the crystalline form. Organic materials are
attractive due to their electronic and optical properties and the molecular structure can be easily
modified for suitable applications. The growth of single crystals has gained much important for
the fabrication of technologically important devices. Triazoles and nitro phenols are capable of
forming predictable hydrogen bonding arrangements. Nitrophenols and their derivatives like
dinitrophenols and trinitrophenols can transfer proton to some inorganic and organic bases to
form stable molecular adducts. In these complexes, phenoxide ion enhances electron donating
character to positively charged partner increasing hyperpolarizability. Number organic crystals
formed between picric acid and triazole derivatives have been thoroughly studied in the recent
past due to their large second order optical nonlinearities, inherent ultra fast response time and
large optical threshold satisfying the technology requirements. Styphnic acid, otherwise known
as 2,4,6-trinitrobenzene-1,3-diol, is an interesting analogue of picric acid [3-6]. Investigations on
molecular adducts synthesized from triazoles and styphnic acid are scarce in literature.
In this research work, we report for the first time structural, spectral characterizations and
optical investigations of a new organic NLO material, 4-amino-4H-1,2,4-triazol-1-ium-3-
hydroxy-2,4,6-trinitrophenolate.

2. Experimental section
2.1. Synthesis
Styphnic acid was prepared by nitrating the resorcinol following Tadeusz Urbanski’s et
al‘s procedure [7]. The reaction scheme is outlined step-1 of Figure 1. The chemicals used in the
synthesis were of analar grade (Sigma-Aldrich). The final product was recrystallized several
times to achieve superior quality. 4-amino-4H-1,2,4 triazole and laboratory synthesized 2,4,6-
trinitrobenzene-1,3-diol (styphnic acid) were dissolved in methanol in 1:1 stoichiometric
proportions separately and the two solutions were mixed to get an yellow color precipitate.
Yellow colored ATHTP crystals were obtained by solution growth-solvent evaporation technique
after ten days. The reaction scheme is shown in the step-2 of Figure 1. Elemental analysis
confirmed the elemental proportions C, H, N analysis: C8H7N7O8 (M.W: 329.21), Calculated
result (%): C, 29.19; H, 2.14; N, 29.78; Found: C, 29.12; H, 2.21; N, 29.56. Important functional
groups and formation of the compound were confirmed by FT-IR spectroscopic techniques. IR
(KBr) (cm−1) selected bonds: υ=3365 (s) (Ar-OH), 3140 (s) (Ar-NH), 2983 (s) (-CH), 1578 (m)
(NO2)asy, 1341 (m) (NO2)sy, 1286 (m) (C-N), 1296 (m) (C-O).
2.2. Characterization techniques
Elemental analysis (CHN) was performed in a flash EA 1112 full automatic trace element
analyzer. The Fourier-transform infrared spectrum of ATHTP was recorded in the region 4000-
400 cm−1 by JASCO FT/IR 5300 infrared spectrophotometer. The optical transmittance of solid
material was measured in
a
JASCO (V-570) UV/VIS/NIR spectrophotometer.
Photoluminescence spectrum of ATHTP crystal was recorded in the wavelength range of 440-
700 nm using Horiba Jobin-Yvon-FL3-22 Flurolog spectroflurometer.

13
1H, C and DEPT-135 NMR spectra were recorded in a Bruker Avance 400 MHz FT-
NMR spectrophotometer with tetramethylsilane as an internal standard using DMSO-d6 as the
solvent. Thermal analyses (TG/DTA) were performed by a Mettler Toledo Star SW 8.10
TG/DTA thermal analyzer in the range 30-800C under nitrogen atmosphere at a heating rate of
20C per minute. Single crystal data were collected using Oxford XCalibur, Gemini
diffractometer equipped with EOS CCD detector at 25C using MoKα radiations (0.71073Å).
The data were reduced using CrysAlisPro Software and absorption correction using multi Ψ-scans.
Structure was solved using SHELXS-97 and refined by full-matrix least squares against F2 using
SHELXL-97 software [8, 9]. Non-hydrogen atoms were refined with anisotropic thermal
parameters. Third-order NLO property of ATHTP was investigated using z-scan technique and in
this measurement, a He-Ne laser (λ= 632.8 nm) was used as the light source.
3. Computational Details
The molecular structure of ATHTP in the ground state was optimized and the structural
parameters have been computed using Gaussian 09 program package at the Becke3-Lee–Yang-
Parr (B3LYP) level with 6-311++G(d,p) basis set [10-13]. First-order hyperpolarizability
calculations have been performed using Gaussian 09 program.
4. Results and Discussion
4.1. Structural Analysis
Single crystal data were collected using Oxford XCalibur, Gemini diffractometer
equipped with EOS CCD detector at 25C using MoKα radiations (0.71073 Å). The compound,
ATHTP, crystallizes in triclinic system. The lattice parameters are a = 7.8000(16) Å, b =
8.9000(18) Å, c = 9.932(2) Å, α = 87.22(3)°, β = 75.97(3)° and = 66.30(3)°. The unit cell

volume (V) is = 611.5(2) Å3 and the number of molecules in unit cell (Z) is 2. The asymmetric
unit consists 4-amino-4H-1,2,4-triazolium moiety and styphnate moiety conforming a proton
migration from styphnic acid to 4-amino-4H-1,2,4-triazol during synthesis.
The C(3)-(O8) bond length (1.328 Å) is a little shorter than found in phenols, (1.36 Å),
which is due to delocalization of the pair of electrons of oxygen onto the adjacent nitro groups in
the styphnate moiety [14]. The C-C-C bond angles at Carbon atoms having nitro groups as
substituents are notably larger than those at C atoms having H atoms as substituents. Bent et al
[15] explained by the strong electron attracting power of the nitro group reducing the s character
of the C σ orbital to the N atom and increasing s character of the C σ orbital to the adjacent C
atoms, thus causing the bond angles to be greater than 120. In agreement with these
observations, the nitro group substituted C atoms in ATHTP have C-C-C bond angles of 127.20
at C (2) and 122.4 at C (6). The lone hydrogen substituted ring C atom has a C-C-C bond angle
of 121.1. The pair of electrons on O (8) of the ring is conjugated with a π bond on the benzene
ring, causing the C(3)-(O8) bond length to be shortened and the C-C(3)-C bond angle to be less
than 120.
The crystal structure is stabilized by the presence of various covalent bonds and hydrogen
bonds like C-H...O, N-H...O and also bifurcated hydrogen bonds. Hydrogen (H1) atom of
styphnate moiety forms bifurcated hydrogen bonding with neighbouring oxygen atom (O1) of
nitro group in the other styphnate moiety and ring nitrogen atom (N5) of triazole moiety through
C-H...O and C-H...N hydrogen bonding. Another hydrogen bond occurs between oxygen atom
(O5) of the styphnate and –CH (C7-H2) of the triazole moiety through C7-H2...O5 hydrogen
bonding. The amino N(7)-H(5b) also participates in the N-H...O hydrogen bonding with oxygen
atom (O3) of nitro group in styphnate moiety. In the ATHTP crystal structure, one of the nitro

groups (O1-N1-O2) is largely deviated from the plane of the benzene ring with an angle of
71.97. The ORTEP, crystal packing diagram, crystallographic data and structural geometrical
parameters of ATHTP are given in Figures. 2, 3 and Tables1, 2, respectively.
4.2. UV-Vis-NIR spectral analysis
The recorded UV-Vis absorption spectrum of ATHTP in methanol solvent is shown in
Figure S1. The spectrum exhibits charge transfer π-π* and n–π* bands of styphnic acid and 4-
amino-4H-1,2,4-triazole moieties of the proton transfer complex salt. This charge transfer arises
due to the promotion of fractional negative charge from donor to the acceptor molecule (i.e.
styphnic acid molecule to the 4-amino-4H-1,2,4-triazole molecule) and appears on the longer
wavelength side of the spectrum at 392 nm. This band confirms the presence of intermolecular
charge transfer activity in ATHTP. The n–π* band of 4-amino-4H-1,2,4-triazole in the complex
salt appears at 258 nm. The π-π* transition of styphnic acid appears at 358 nm.
UV-Vis-NIR transmittance spectrum of ATHTP recorded in the solid state is shown in
Figure 4. The transmittance of grown crystal ATHTP was recorded in the range 200-1400 nm.
There is no considerable absorption of light within the entire visible range. The lower cut off the
grown crystal is around 290 nm and it is an essential parameter for frequency doubling process
using diode and solid state laser [16]. The absence of the absorption in the visible range of the
crystal is incredibly helpful in opto electronic applications.
4.3. Photoluminescent properties
Fluorescence occurs generally in molecules that are aromatic or having conjugated
double bonds with a high degree of resonance stability. The study of photoluminescence is of
great current interest because of its applications in chemical sensors, photo chemistry and

electroluminescent display. The powdered sample of ATHTP was significantly more intense
green emission in the electro-magnetic spectrum with a maximum at 490 nm (λex = 440 nm). It
shows an efficient luminescence in the longer wavelength ranges it shown in Figure 5. The
results indicate that the ATHTP crystal has a green emission property suggesting that it can be
used for display and solid-state lightening applications [17].
3.1.
4.4. Thermal analysis
The TG/DTA thermogram (Figure 6) of ATHTP exhibits no thermal events till 178C
before the start of the decomposition illustrating the absence of physically adsorbed or lattice
water in the crystal. The DTA curve of ATHTP shows an endothermic peak at 178 C which can
be attributed to the melting point of the sample. The sharpness of endothermic peak shows the
good degree of crystallinity and purity of the sample. The TG curve shows that a single stage
weight loss (>85%) occurring between 178 C and 500C. With temperature increasing, volatile
substances such as ammonia and CH4, NO2 and CO molecule get liberated. The final residue is
carbon.
4.5. NMR Spectral Studies
1H and 13C NMR spectra were recorded with tetramethylsilane as an internal standard
1
using DMSO-d6 as the solvent which are shown in Figure 7. The H NMR spectrum of the
ATHTP shows three proton signals indicating the presence of three different proton
environments in the molecule. The δ value of C(5)-H proton is observed in up field at δ 8.6 ppm
in styphnate moiety. The singlet at δ 6.8 ppm is due to the presence of –NH2 proton of triazole
moiety. The peak at δ 9.5 ppm is due to presence of two –CH protons present in triazole moiety.
The solvent peak is observed at δ 2.5 ppm for DMSO-d6 solvent. The N-H+ proton of triazole

moiety in the complex is far downfield shifted and does not appear in the spectrum [18]. The
signal for hydroxyl proton is also far shifted to downfield which is also not seen in the spectrum
due to deshielding effect of oxygen atom [19].
In general, aromatic carbons give signals with chemical shift values from 100 to 200 ppm
[20]. The experimental chemical shifts of the compound occur in the range of δ 125.8-156.1 ppm.
The external magnetic field experienced by the carbon nuclei is affected by the electronegativity
of the atoms attached to them. The chemical shift of equivalent carbons (C1, C3) is observed in
the downfield at δ 156.1 ppm due to their attachment with more electronegative oxygen atom.
The carbon atoms C4 and C6 are chemically equivalent so the lone signal for these two carbon
atoms occurs at δ 135.4 ppm. The signal for C2 carbon which is attached to nitro group appears
at δ 125.8 ppm. The chemical shift of C5 carbon atom appears at 126.2 ppm. The other signal
observed at δ 144.4 ppm is due to presence of two chemically equivalent carbons (C7, C8)
present in the triazole moiety. The solvent peak (DMSO-d6) is observed at around δ40 ppm.
Presence of different types of -CH, CH2 and CH3 carbons can be clearly identified using
DEPT-135 spectral analysis. The signals observed at δ 126.2 and 144. 4 ppm are due to CH (C5)
of styphnate moiety and CH (C7, C8) of triazole moiety. The DEPT-135 NMR spectrum of
ATHTP is shown in Figure S2.
4.6. Optimized geometry
The optimized molecular structure of ATHTP was calculated using, B3LYP/6-
311++G(d,p) level of basis set. It is found that most of the optimized bond lengths are slightly
higher than the experimental values. The deviations can be attributed to the fact that the
theoretical calculations were performed assuming isolated molecules in the gaseous phase and
the experiments were conducted using crystals [21, 22].

The molecule is stabilized by inter- and intra-molecular hydrogen bonding. Out of the
three hydrogen bond interactions, N-H...O and C-H…O are found to be intermolecular in nature.
The O-H…O hydrogen bond is intramolecular. The molecular structure of ATHTP with atom
numbering scheme adopted in the computations is given in Figure 8.
The dihedral angle of 159.6º pertaining to C13-C19-N10-O24 and -18.6º to
C13-C19-N10-O23 confirm that the nitro group is coplanar with phenyl ring. The hydrogen bond
distance of O25-H26….O23 (2.48Aº) and O-H-O angle (146.5º) confirm O-H….O intramolecular
hydrogen bonding. The decrease in endocyclic angle C19-C9-C16 (113.9º) and increase in
exocyclic angles C16-C9-O27 (123.5º) and C19-C9-O27 (122.4º) from expected 120 confirms
the intermolecular hydrogen bonding in the ring moiety.
O27 of the styphnate forms bifurcated hydrogen bonds O27…H29-N4 and O27….H28-
C6 with the triazole moiety. (H28) of triazole moiety also participates in the bifurcated hydrogen
bond with two oxygen atoms (O24 and O27) of styphnate moiety viz., C6-H28…O24 and
C6-H28…O27. The elongation of N4-H29 and N1-C7 bond length values compared to other N-
C and N-H bonds confirms the formation of intermolecular hydrogen bonding, O27…H29-N4.
There is an increase in bond length of N4-H29, viz., 1.37 Å due to hydrogen bonding whereas
the bond length of N4-H30 is unaffected (1.032 Å).
4.7. Hyperpolarizability calculations
Quantum chemical methods were used for assessing the molecular NLO property of
ATHTP. Hyperpolarizability is useful in understanding the relationship of the structure depended
their nonlinear properties. Polarizability (α0) and first-order hyperpolarizability (β) of ATHTP
were calculated using B3LYP/6-311++G(d,p) level of basis set. The calculated β value is very
useful as this clearly indicates the direction of charge delocalization or polarization. The

calculated first-order polarizability (β) and the ground state dipole moment (μg) of synthesized
crystal is 3.89 x 10-30esu. Table 4 shows that βtot has the largest calculated value for ATHTP
crystal while βtot is comparably decreased for the constituents such as styphnic acid and 4-amino-
4H-1,2,4-triazole of the ATHTP crystal. The total first-order polarizability (β) in the ATHTP
crystal is approximately 30 times greater than that of urea (0.13x10-30 esu). Comparison of static
first hyperpolarizability for the constituents of ATHTP is shown in Table 3.
4.8. Hirshfeld surface analysis
Hirshfeld surface depends on the geometry of the molecules, orientation of the molecules
in the neighborhood and the nature of atoms that make close contacts in the chosen molecule. In
other words, it gives a detailed explanation on the immediate environment of a molecule in a
crystal. For each point on the surface, two distances are defined; de, the distance from the point
to the nearest nucleus external to the surface and di, the distance to the nearest nucleus internal to
the surface. These are useful in exploring the type (C–H…π, O–H…O, H…H etc.) as well as the
proximity of intermolecular contacts in a molecular crystal. The dnorm surface (de+di) shows
intermolecular contacts relative to the van der Waals radii by way of a simple red, white and blue
color scheme: red indicating higher electron density and hydrogen bonding capability and blue
representing lower electron density site [23].
Curvedness is a measure of curvature in Hirshfeld surface. Low values of curvedness are
associated with essentially flat areas of the surface, while areas of sharp curvature possess a high
curvedness and tend to divide the surface into patches associated with contacts between
neighboring molecules. The low curvedness suggests close contacts and this is possibly
indicative of covalent bonding interactions [24]. The large flat region indicated by a blue outline
on the curvedness surfaces indicates π…π stacking of the molecules. The shape index is the

measurement of shape of Hirshfeld surface. The red triangles on shape index represent concave
regions indicating atoms of the π…π stacked molecule above them and the blue triangles
represent convex regions indicating the ring atoms of the molecule inside these surfaces. Figure
9 represents Hirshfeld parameters, curvedness, shape index and dnorm and 2D fingerprint plot of
ATHTP crystal. Hirshfeld two-dimensional (2D) fingerprint plots offer considerable promise for
exploring packing modes and intermolecular interactions in molecular crystals. This analysis
allows a quick and easy identification of the significant intermolecular interactions map on the
molecular surface. CrystalExplorer, a computer program was used for calculation of Hirshfeld
surfaces and 2D fingerprint plots [25].
The larger circular depressions (deep red) visible on the side of the 3D Hirshfeld surfaces
correspond to the significant hydrogen bonding contacts. While the red color points indicate the
short contacts of H...H, N…H and H...O interactions. The proportion of O…H/H…O interactions
covers 37.4% of the total Hirshfeld surfaces with two distinct spikes in the 2D fingerprint plots
indicating hydrogen bonding interactions are the most significant interactions in the crystal. The
H…H interactions, which are reflected in the middle of scattered points in the 2D fingerprint plot
comprise 12.2% of the total Hirshfeld surfaces. Apart from the above interactions, the presence
of π…π (C…C), lone pair….π (N…C, O…C) and lone pair…lone pair (O…O, N…N and
O…N) interactions are also observed. The C-H…π interactions also have a small contribution to
the total Hirshfeld surfaces of ATHTP.
4.9. z -scan analysis
Z-scan technique is a standard technique for determining the nonlinear index of refraction
(n2) and nonlinear absorption coefficient (β) in solids, liquids. The Z-scan technique is a straight
forward method using which the nonlinear optical coefficient can be measured with a high

degree of accuracy. The study of nonlinear refraction by the Z-scan method depends on the
position (Z) of the thin sample under investigation along a focused Gaussian laser beam. The
sample causes an additional focusing and defocusing depending on whether nonlinear refraction
is positive or negative. Measurements of open and closed apertures are shown in Figure 10. The
third-order nonlinear optical parameters can be calculated using standard equations [26]. The
estimated nonlinear refractive index (n2) and absorption coefficient (β) and third-order
susceptibility (3) of ATHTP crystal are 1.06 x 10-7 cm2/W and 4.05 x 10-4 cm/W and 2.1 x 10-7
esu respectively. The positive value of refractive index reveals the self-focusing nature and the β
value exhibits the two-photon absorption process and the absolute susceptibility value is due to
the π-electron cloud movement from the donor to acceptor which makes the molecule highly
polarized [27, 28].
5.
Conclusion
Single crystals of 4-amino-4H-1,2,4-triazolium styphnate were grown from saturated
solution by slow evaporation method at room temperature. Various spectral techniques such as
FTIR, 1H, 13C and DEPT-135 NMR confirmed the molecular structure of ATHTP. The structure
of ATHTP was confirmed using single crystal X-ray diffraction studies and ATHTP belong to
triclinic system. The crystal structure is stabilized by the presence of various covalent bonds and
hydrogen bonds C-H...O, N-H...O and also bifurcated hydrogen bonds. The cut off wavelength
of ATHTP from the transmittance spectrum is 290 nm and excitation of luminescence spectrum
suggests the suitability of ATHTP crystal for various opto electronic applications and it can be
used as a new green-light emitting material. The thermal stability of the title crystal was
determined by TG-DTA studies and it can be exploited for any application up to 178C. The
third-order nonlinear optical susceptibility is found to be 2.1 x 10-7 esu. The nonlinear refractive

index indicates that ATHTP exhibits self-focusing optical nonlinearity. Quantum chemical
calculations show that the first-order polarizability (β) of synthesized crystal is 3.89 X10-30esu.
First-order hyperpolarizability (β) of ATHTP is 30 times greater than that of urea. Thus ATHTP
can act as a promising material for nonlinear optical applications and it can also possibly be used
for the fabrication of electro optic devices. Hirshfeld surface analysis of ATHTP crystal
demonstrated that among the different kinds of interactions, O…H is more prominent.
Acknowledgements
One of the authors, Dr. M. Dhandapani, would like to thank the University Grants
Commission (UGC), New Delhi, India for the financial support (Major Research Project Grant
No. 43-200/2014(SR) to carry out the research work. P. Dhamodharan, thanks the
Dr. R. Nagarajan, School of Chemistry and UGC Networking Centre, Hyderabad, for awarding
visiting research fellowship.
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[28] Y. S. Zhou, E. B. Wang, J. Peng, Polyhedron 18 (1999) 1419.
Figure 1 Synthesis of styphnic acid and 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-
trinitrophenolate
Figure 2 Asymmetric unit of the compound with atomic labeling scheme at 50% probability level
Figure 3 Packing diagram of ATHTP along a, b and c axis
Figure 4 UV-Vis-NIR spectrum of ATHTP
Figure 5 Phosphorescence emission spectrum of ATHTP
Figure 6 TG/DTA curves of ATHTP
Figure 7 1H and 13 C NMR spectra of ATHTP
Figure 8 Optimized molecular structure of ATHTP

Figure 9 Hirshfeld dnorm, Shape index, Curvedness and fingerprint plots of ATHTP
Figure 10 Z-scan patterns in open and closed aperture.
Figure 1

Figure 2
Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Table 1: Crystal data and structure refinement for ATHTP Crystal
Empirical formula
Formula weight
Temperature
C8 H7 N7 O8
329.21
298(2) K
Wavelength
0.71073 Å
Triclinic
Crystal system
Space group
P-1
Unit cell dimensions
a = 7.8000(16) Å
b = 8.9000(18) Å
c = 9.932(2) Å
= 87.22(3)°.
= 75.97(3)°.
 = 66.30(3)°.
3
Volume
Z
611.5(2) Å
2
3
Density (calculated)
1.788 Mg/m
-1
Absorption coefficient
F(000)
0.161 mm
336
Crystal size
0.18 x 0.15 x 0.12 mm
2.12 to 26.24°.
Theta range for data collection
Index ranges
-9<=h<=9, -11<=k<=11, -12<=l<=12
Reflections collected
Independent reflections
Completeness to theta = 26.24°
6459
2437 [R(int) = 0.0198]
98.6 %
Refinement method
Full-matrix least-squares on F2
Data / restraints / parameters
2437 / 0 / 210
Goodness-of-fit on F2
Final R indices [I>2sigma(I)]
R indices (all data)
1.053
R1 = 0.0525, wR2 = 0.1574
R1 = 0.0554, wR2 = 0.1611
0.097(13)
Extinction coefficient
Largest diff. peak and hole
0.530 and -0.526 e A-3
CCDC:
1034328

Table 2: Comparison Bond lengths [Å] and Bond angles [°] of ATHTP molecule
Atoms
Observed
Calculated
1.341
1.375
1.402
1.246
1.469
1.449
1.257
1.232
1.424
1.222
1.230
1.464
1.227
1.377
1.454
1.234
1.329
1.357
1.304
1.387
1.412
1.316
1.431
Atoms
Observed
Calculated
N(6)-C(7)
N(6)-C(8)
N(6)-N(7)
C(3)-O(8)
C(3)-C(2)
C(3)-C(4)
N(1)-O(1)
N(1)-O(2)
N(1)-C(2)
N(3)-O(5)
N(3)-O(6)
N(3)-C(6)
O(4)-N(2)
C(4)-C(5)
C(4)-N(2)
N(2)-O(3)
N(4)-C(7)
N(4)-N(5)
N(5)-C(8)
C(6)-C(5)
C(6)-C(1)
C(1)-O(7)
1.323
1.347
1.399
1.328
1.367
1.407
1.205
1.206
1.449
1.212
1.213
1.443
1.208
1.377
1.417
1.241
1.296
1.357
1.293
1.365
1.434
1.246
C(7)-N(6)-C(8)
C(7)-N(6)-N(7)
C(8)-N(6)-N(7)
O(8)-C(3)-C(2)
O(8)-C(3)-C(4)
C(2)-C(3)-C(4)
O(1)-N(1)-O(2)
O(1)-N(1)-C(2)
O(2)-N(1)-C(2)
O(5)-N(3)-O(6)
O(5)-N(3)-C(6)
O(6)-N(3)-C(6)
C(5)-C(6)-C(1)
C(5)-C(6)-N(3)
C(1)-C(6)-N(3)
O(7)-C(1)-C(2)
O(7)-C(1)-C(6)
C(2)-C(1)-C(6)
C(5)-C(4)-C(3)
C(5)-C(4)-N(2)
C(3)-C(4)-N(2)
O(4)-N(2)-O(3)
107.07
123.14
129.77
118.55
124.92
116.52
122.8
107
127.9
124.7
122.4
123.5
113.9
119.7
119
118.57
118.59
122.31
118.09
119.6
121.2
124.6
116.7
118.6
120.9
117
122.47
116.73
120.78
120.49
127.32
112.19
120.05
119.09
120.84
121.59
121.9
122.8
119.5
117.5
122.1
116.9
120.8
118
C(1)-C(2)
1.418
115.75
103.51
106.3
121.55
112.09
O(4)-N(2)-C(4)
N(5)-C(8)-N(6)
O(3)-N(2)-C(4)
C(3)-C(2)-C(1)
C(3)-C(2)-N(1)
120.33
111.1
118.08
127.21
117
118.6
111.1
122.7
118.8
118.4
C(1)-C(2)-N(1)
C(8)-N(5)-N(4)
N(4)-C(7)-N(6)
C(6)-C(5)-C(4)
C(7)-N(4)-N(5)
112.9
103.6
105.2
121.9
121.9
RMSD values for Bond lengths and Bond angels are 0.03821Å and 3.413, respectively.
*Calculated from optimized structure from DFT.

Table 3: Comparison of static first hyperpolarizability for the constituents of ATHTP
Hyperpolarizability
Styphnic acid
4-amino-4H-1,2,4-
triazole
ATHTP
tensor
xxx
yyy
zzz
0.0047
-21.5119
-0.0001
-46.595
0.0017
0.0001
-381.98
-58.17
1.299
xyy
xxy
xxz
xzz
-0.004
47.9402
0.0032
-15.3840
0.000
-0.0001
-50.47
16.379
8.116
3.047
-0.0003
0.3413
yzz
yyz
-11.4252
-0.0010
0.0001
0.0007
-2.398
11.283
xyz
β total
3.6845
-0.0001
-15.190
0.1295*10-30 esu
0.535*10-30 esu
3.89*10-30 esu
Highlights





Single crystals were grown by slow evaporation solution growth technique.
N-H…O, O-H...O and C-H…O type of interactions lead to stable network.
The thermal stability of the compound was investigated by TG/DTA analyses.
The third-order nonlinear optical susceptibility is found to be 2.1 x 10-7 esu.
Hirshfeld analyses explore covalent and non covalent interactions.