UV absorbers for cellulosic apparels: A computational and experimental study

Article abstract of DOI:10.1016/j.saa.2017.07.037

Two triazine based Ultra Violet (UV) absorbers Sulfuric acid mono-(2-{4-[4-chloro-6-(4-{4-chloro-6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino-phenylamino)-[1,3,5]triazin-2-ylamino]-benzenesulfonyl}-ethyl) ester (1a) and 4-{4-chloro-6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino}-2-[4-chloro-6-(2-sulfooxy-ethanesulfonyl)-[1,3,5]triazin-2-ylamino]-benzenesulfonic acid (2a) with different substituents were designed computationally. The influence of different substituents on the electrochemical properties and UV spectra of the absorbers was investigated. The presence of electron deficient unit in 1a to the molecular core significantly reduces the LUMO levels and energy gap. The designed absorbers were synthesized via condensation reaction and characterized by UV–Vis, FT-IR, MS studies. The performance of synthesized compounds as UV absorbers and their fastness properties were assessed by finishing the cotton fabric through exhaust method at different concentration and results appeared in good range.

Full text of DOI:10.1016/j.saa.2017.07.037

Accepted Manuscript
UV absorbers for cellulosic apparels: A computational and
experimental study
Anum Sahar, Shaukat Ali, Tanveer Hussain, Muhammad Irfan,
Bertil Eliasson, Javed Iqbal
PII:
DOI:
Reference:
S1386-1425(17)30600-5
doi: 10.1016/j.saa.2017.07.037
SAA 15324
Spectrochimica Acta Part A: Molecular and Biomolecular
Spectroscopy
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Revised date:
Accepted date:
11 February 2017
9 July 2017
20 July 2017
Please cite this article as: Anum Sahar, Shaukat Ali, Tanveer Hussain, Muhammad Irfan,
Bertil Eliasson, Javed Iqbal , UV absorbers for cellulosic apparels: A computational
and experimental study, Spectrochimica Acta Part A: Molecular and Biomolecular
Spectroscopy (2017), doi: 10.1016/j.saa.2017.07.037
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ACCEPTED MANUSCRIPT
UV absorbers for Cellulosic Apparels : A Computational
and Experimental Study
Anum Sahar a, Shaukat Ali*a, Tanveer Hussain, Muhammad Irfan, Bertil Eliassond,
Javed Iqbal*a,c
a Department of Chemistry, University of Agriculture, Faisalabad, Pakistan
b Department of Textile Processing, National Textile University, Faisalabad, Pakistan
c Punjab Bio-energy Institute, University of Agriculture, Faisalabad, Pakistan
d
Department of Chemistry, Umea University, Umea, 90187, Sweden
Corresponding author: E-mail: javedkhattak79@gmail.com.javed.iqbal@uaf.edu.pk (J. I),
shaukatchemist@hotmail.com
Abstract
Two triazine based Ultra Violet (UV) absorbers Sulfuric acid mono-(2-{4-[4-chloro-
6-(4-{4-chloro - 6 - [ 4 - (2-sulfooxy - ethanesulfonyl) - phenylamino] - [1,3,5] triazin-2-
ylamino-
phenylamino)-[1,3,5]triazin-2-ylamino]-benzenesulfonyl}-ethyl) ester (1a) and 4-{4-Chloro-
6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino}-2-[4-chloro-6-(2-
sulfooxy-ethanesulfonyl)-[1,3,5]triazin-2-ylamino]-benzenesulfonic acid (2a) with different
substituents were designed computationally. The influence of different substituents on the
electrochemical properties and UV spectra of the absorbers was investigated. The presence
of electron deficient unit in 1a to the molecular core significantly reduces the LUMO levels
and energy gap. The designed absorbers were synthesized via condensation reaction and
characterized by UV-Vis, FT-IR, MS studies. The performance of synthesized compounds as

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UV absorbers and their fastness properties were assessed by finishing the cotton fabric
through exhaust method at different concentration and results appeared in good range.
Key Words: Solar Radiations, Substituents effect, UV Absorbers, DFT, HOMO-LUMO,
Condensation reaction
Introduction
Solar radiations are increasingly valued due to their influence on living and non-living
material. Among these solar radiations, UV radiations pose severe threat to human body due
to their high energy contents [1-4]. Clothing is a most well-known practice for protection
point of view from these radiations and today, cotton fiber is the most used textile fiber which
gives 56 percent share for home and apparel but offered low ultraviolet protection due to low
weight and high porosity [5]. Subsequently, the global demand for new UV absorbers for
cotton fiber is nowadays of great interest as a result of augmented awareness about harmful
effects of UV rays [6].
So a serious consideration has been given to synthesize the textile fabrics which can
play the role of a shield between humans and unhealthy UV radiations. An effective UV
absorber must include; i) effective absorptions of UV rays especially in UV-B (320–400 nm)
and UV-A (280–320 nm) regions [7] ii) rapid transformation of UV energy into vibration
energy then convert it into heat energy in the surroundings without degradation of fabric and
iii) easy application on fabric without addition of colour [5, 8].
For designing the compounds of our interest, quantum mechanical calculations are
tremendously potent tools [9, 10] Computational study provides us a great help in theoretical

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calculations such as wavelength [11-13] and energetic properties [14-16] of chemical systems
in general and offer opportunity to mould desirable chemical and physical properties
containing molecular systems that reduce the loss of resources [17, 18]. The predicted
structures of desirable properties then become a target for synthesis [19]. Moreover,
meanwhile in this study our aim was to computationally design new UV absorbers and
investigate their electrochemical properties and excited state properties and later on
synthesize the molecules with desire properties. After careful assessment of calculated UV
properties of designed molecules, two molecules Sulfuric acid mono-(2-{4-[4-chloro-6-(4-{4-
chloro - 6 - [ 4 - (2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5]triazin-2-ylamino}-
phenylamino)-[1,3,5]triazin-2-ylamino]-benzenesulfonyl}-ethyl) ester (1a) and 4-{4-Chloro-
6-[4-(2-sulfooxy-ethanesulfonyl)-phenylamino]-[1,3,5] triazin-2-ylamino}-2-[4-chloro-6-(2-
sulfooxy-ethanesulfonyl)-[1,3,5]triazin-2-ylamino]-benzenesulfonic acid (2a) were
synthesized and their UV property was investigated. Furthermore, ultraviolet protective and
fastness properties of these absorbers have been evaluated to define their efficiency.
Computational Methods
In search of the best UV absorber for cotton apparels and to authenticate the most suitable
computational methodology to tailor such compounds computational approach was employed
by using DFT and TD-DFT level of theory [17]. Primarily, the 3D structure of UV absorbers
were created with the Gauss view [16] and executed initial conformational analysis,
optimization of geometries were carried out without any structural or symmetry restrictions
using DFT theory with three functionals CAM-B3LYP [20], WB97XD [21], B3LYP [22]
and the basis set 6-31G(d,p) [23, 24] was implemented in the Gaussian 09 package [25].
Geometry optimization generated different conformers that were submitted to frequency
calculations in order to detect the absence of imaginary frequencies, ensuring that the
obtained conformation is an energetic minimum of the simulated compound.

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Then, excited sates of the molecules were calculated by employing TD-DFT level of theory
from the ground states of the optimized geometries with above said functional aiming to
calculate the UV-Vis spectra. All calculations were performed employing the implicit
solvation model IEFPCM [26] with water as solvent because it is used as solvent for finishing
of cotton. From DFT and TD-DFT calculations, several structural and electronic properties
were calculated, such as molecular orbital energies as well as its contribution to electronic
transition.
Experimental
Materials and Apparatus
Bleached mercerized 100% cotton fabric with plain weave weighing 97.8 g/m2 was
used throughout this work. All chemicals as well as solvents were procured from sigma
Aldrich, Merk and Fluka. Solvents were of analytical grade used without further purification.
Thin layer chromatography (TLC) was performed on Merk Cellulose F254 plate.
Spectroscopic measurements of synthesized UV absorbers in UV-Vis range, FT-IR studies
and Mass spectra were taken on Perkin Elmer (CE-7200) spectrophotometer, Perkin Elmer
(U-2001) and MALDI (matrix assisted laser desorption ionization) technique respectively.
Application tests on fabric were carried out on a HD-12E exhaust machine by general
procedure for monochlorotriazine reactive dyes. The UV transmittance measurement through
fabric was carried out with spectrophotometer (Beckman DK-2A). Whiteness Index of treated
fabrics was taken on Gretag Macbeth SpectroEye spectrophotometer. Light fastness tests
were carried out with the use of Xenotest (XF-15N Shimadzu).
Synthesis: Heterofunctional two new reactive triazine based UV absorbers 1a and 2a were
synthesized by following a condensation method as shown in scheme 1 [6].
Synthesis of UV absorber (1a) : For UV absorber (1a), solution of 1, 3-phenylendiamine-4
sulfonic (m-PDA) acid (1 mole) was added in cyanuric chloride suspension (2 mole,

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dispersed in ice water) slowly with constant stirring (Temp. 0-5°C, pH 3-3.5) and completion
of first condensation was confirmed through thin layer chromatography (Merk Cellulose F254
plate). To the above filtrate 4-(β-hydroxyethyl)sulphonylaniline solution (2 moles, 10%
Na2CO3, Temp. 40-45°C, pH 6-6.5) was added and second condensation was considered as
completed after the vanishing of free amine tested with Ehrlich reagent. Finally synthesized
compound was isolated by salting out (KCl), filtered, stabilized (phosphate buffer pH 7.0)
and dried at 40˚C.
Synthesis of UV absorber (2a): 2a was prepared by following the above mentioned
procedure but p-phenylenediamine was used instead of 1, 3-phenylendiamine-4 sulfonic (m-
PDA) acid.
Finishing Procedure : Finishing of cotton fiber with reactive UV absorbers was carried out
with general procedure of exhaust dyeing of cotton at liquor-fabric ratio of 30:1 as in the case
of monochlorotriazine reactive dyes cited in literature [6]. The application bath exhaustion%
was measured by using UV/Vis spectrophotometer (CE-7200) at λmax with 1cm quartz cells
for all UV absorbers. UV absorber exhaustion percentage was calculated from equation (1).
[ ( )]
Where C1 is the concentration of the application bath before and C2 is the
concentration of the application bath after finishing [27].
Determination of Ultraviolet Protection Factor (UPF) and Fastness Properties:
Ultraviolet protective property of finished cotton fabrics was evaluated using AATCC TM
183 test method. Durability of finished applied on fabric under laundry conditions is
extremely important and fastness properties have to be assessed. The finished fabric was
tested according to ISO standard methods. Whiteness of all treated samples was measured

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after introducing UV absorbers and after their exposure to UV radiations by Xenotest
apparatus.
Results and discussion
Frontier Molecular Orbital : Geometries of UV absorbers 1a and 2a were optimized
without imposing any constraint. The geometry optimization shows that both the UV
absorbers demonstrate structural similarities, since they possess the same triazine and vinyl
sulphone paraester moieties. The structural difference results from different substituent
attached with bridging moiety. Afterwards, molecular orbital calculations were carried out.
Table 1 shows the HOMO-LUMO and HOMO-1-LUMO+1 energy levels and energy gaps of
these absorbers 1a and 2a respectively with CAM-B3LYP, B3LYP and WB97XD at 6-31G
(d,p) basis set employed in Gaussian 09 program. Comparison of the calculated HOMO-
LUMO and HOMO-1 to LUMO+1 energy gaps reveals that the ΔE increases as follows:
1a<2a, in all the three approaches, showing that the SO3H unit produce opposite effects on
the energy gap when compared with –H unit due to electron withdrawing nature of SO3H
unit.
The calculated energy gap between HOMO and LUMO for 1a is 7.43, 4.91 and 8.71
eV with CAM-B3LYP, B3LYP and WB97XD respectively and same for 2a is 7.77, 5.06 and
8.77eV (Table 1). Due to high values of the calculated energy gap, it is anticipated that these
molecules will absorb in the shorter region of the UV-Vis spectrum. As 2a shows greater
energy gap values with respect to 1a, so 2a will absorb in lower region of spectrum as
compared with 1a which is consistent with experimental results. Moreover due to high levels
of the HOMO’s and low levels of LUMO’s, it is predicted that most of the excitations are
from the HOMO to LUMO or HOMO to LUMO+1. The energy values of HOMO, HOMO-1
and HOMO-2 are relatively very close therefore they appear in the same energetic region.
HOMO and LUMO sketches of 1a and 2a are shown in Fig. 1.

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HOMO and LUMO distribution pattern of 1a and 2a is almost same with little
difference due to presence of substituent on benzene ring. It is clear from the distribution
pattern from Fig. 1 that HOMO of 1a is mostly localized over two triazine rings and
phenylendiamine sulphonic acid ring while HOMO-1 is spread over one triazine ring and
aniline ring. The LUMO of 1a is spread over one triazine ring, aniline ring and little bit on
phenylendiamine sulphonic acid ring while LUMO+1 is mostly localized over two triazine
rings, phenylendiamine sulphonic acid ring and aniline ring. The HOMO of 2a is present on a
triazine ring, phenylendiamine group and slightly on second triazine ring while HOMO-1 is
spread over a triazine ring, aniline ring and slightly on sulphonyl group. LUMO and
LUMO+1 of 2a are distributed over a triazine ring, aniline ring with little contribution on
sulphonyl group of other/opposite side chain.
Density of States (DOS): Density of the states (DOS) of the molecule 1a and 2a were also
calculated with CAM-B3LYP/ 6-31G (d,p) and shown in Fig. 2. The results of density of
state contribution supported the facts demonstrated by the frontier molecular orbital. Further
evaluation of FMOs regarding percentage composition in addition to DOS around HOMOs as
well as LUMOs also confirmed that components with different electron withdrawing or
donating intensities may change the distribution of electron on molecular orbitals. Similarly,
the DOS demonstrates the energies of all the occupied as well as unoccupied MOs of these
UV absorbers.
Synthesis :The designed target UV absorbers (1a and 2a) were prepared and their structure
elucidated by spectroscopic techniques. The first step comprises the nucleophilic substitution
of first Cl-atom of s-triazine by NH2 of diamine through first condensation reaction to yield (I
and II respectively) with an efficient yield. The second Cl-atom is substituted by NH2 of 4-
(β-hydroxyethyl)sulphonylaniline through second condensation reaction to give final
products which were further characterized by UV-Vis., FT-IR and ESI-MS studies.

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UV absorber (1a)
Colour: colourless, Yield: 75%; Molecular formula; C28H23Cl2N10Na3O16S5, UV/Vis. spectra
in water (λmax): 292 nm, IR (KBr cm-1):3433 (N-H), 3007(N-H), 1408 (C-N in aromatic
amine), 1135(C-S), 840(C3N3-s-triazine), 736(C-Cl); ESI-MS: m/z 994[M (Na, K salt)]-, m/z
972[M-Na]-, m/z 323[M-2Na-K/3]- were detected.
UV absorber (2a)
Colour: colourless, Yield: 81%; Molecular formula; C28H24Cl2N10Na2O12S4, UV/Vis. spectra
in water (λmax ): 282 nm, IR (KBr cm-1):3417 (N-H), 3007(N-H), 1442 (C-N in aromatic
amine), 1116(C-S), 831(C3N3-s-triazine), 736(C-Cl); ESI-MS: m/z 913[M-Na ]-, m/z 445[M-
2Na/2]- were detected.
Optical Properties
Comparison of experimental and theoretically measured UV-Vis spectra of 1a and 2a with
B3LYP, CAM-B3LYP and WB97XD at 6-31G (d,p) is shown in Fig. 3. The UV-Vis
spectrum of 1a consists of two absorption band, one absorption band in low energy region
260 nm to 300 nm and other in higher energy region below 255 nm for the CAM-B3LYP and
WB97XD. The higher energy band for B3LYP is ranging from 250 nm to 290 nm and lower
energy absorption band is above 290 nm. The low energy electronic transition is due to
HOMO to LUMO and HOMO to LUMO+1 overlapping (Table 2). The relatively high
oscillator strength (f) values of 1a are due to π-π* electronic transitions and these peaks show
relatively strong molecular orbital overlapping. The larger oscillator strengths are due to
better overlapping of HOMO to LUMO+1 transition. As HOMO of 1a is mostly localized
over two triazine rings and phenylendiamine sulphonic acid ring while the LUMO of 1a is
spread over one triazine ring, aniline ring and little bit on phenylendiamine sulphonic acid
ring while LUMO+1 is mostly localized over two triazine rings, phenylendiamine sulphonic

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acid goup and aniline ringwhich describe the strong overlapping of the triazine and
phenylendiamine sulphonic acid rings.
The UV-Vis spectrum of 2a consists of one absorption band in low energy region
ranging from 250 nm to 320 nm. Absorber 2a shows low oscillator strength which is due to
weak overlapping of molecular orbital in electronic transition. The low molecular orbital
transition is due to HOMO of 2a is present on a triazine ring and, phenylendiamine ring while
LUMO and LUMO+1 of 2a are distributed over a triazine ring, aniline ring with little
contribution on sulphonyl group of opposite side chain.
It is important to control the substitution effect on molecular levels which can be best
achieved by TD-DFT simulations. Low energy bands are mainly affected by substitution
patterns which may change the HOMO levels of the compounds. In case of 2a the Cl-atoms
are present on two triazine rings which extend the π-delocalization on triazine rings. Cl-atoms
stabilize the HOMO than LUMO due to its inductive effect (-I), which results in greater
HOMO-LUMO energy gap. A blue shift observed and 2a have λmax at 282 nm. Introducing
the –SO3H group on phenylendiamine ring in 1a changes the π-delocalization and can
change the HOMO levels which results in bathochromic shift of this absorber. The absorber
1a shows λmax at 292 nm.
Ultraviolet Protective Factor and Fastness Properties
Both the synthesized UV absorber absorbs light in the UV-range of 280-400 nm that is
specific for UV absorbers. Substantivity of these absorbers was measured during testing on
cotton fabric and exhaustion % values of absorbers (1a-2a) and commercially available
absorber (Rayson C Liquid) are enlisted in Fig 4. It can be seen that exhaustion %age
decreases as the concentration of the UV absorber increases and it is above 72% in all the
concentrations applied in this study. Maximum exhaustion on fabric is shown at 1%

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concentration of the UV absorber. It is clear from the results shown in Fig. 4 that synthesized
UV absorbers (1a-2a) have good and comparable exhaustion properties on fabric with
commercially available absorbers in market.
According to Australian standard [2], ultraviolet protective factor (UPF) ranges are
depicted in Table 3. Results of UPF of treated fabric with UV absorber (1a-2a) and
commercially available absorber (Rayson C Liquid) and un-treated fabric are graphically
presented in Fig. 5. The treated fabric fall in very good UPF range at 3% concentration of UV
absorber (1a-2a) when compared to untreated cotton fabric but have low value of UPF than
commercially available UV absorber which fall in excellent range at same concentration. It is
crystal clear from results that both the UV absorbers increased the UPF of fabric as the %
concentration increase but they impart slightly yellowish colour at 5% on white fabric. In the
case of absorber (1a), which absorb UV light more and give good improvement in protecting
properties as compared to absorber (2a) but less than commercially available absorber
“Rayosan C Liquid” for cellulosic fibers. This behaviour may be due to high exhaustion of
absorber (1a) than absorber (2a).
UPF of treated fabric was also measured after several washes. The UPF was measured
after each washing and repeated it ten times. Treated fabric with UV absorbers (1a-2a)
remains in good range of UPF for 1a and for 2a it is in very good range of UPF. It is also
clear from the Fig. 6 that the UPF factor is almost remain same after ten washes (little bit
reduction in UPF) for 1a and 2a. Both UV absorbers are also in fairly good agreement in
terms of UPF with the commercially available absorbers in market after ten washings as
shown in Fig 6. This study revealed that designed UV absorber 1a and 2a have very good
washing fastness properties.
Xenotest was also employed to test the light fastness of absorbers Fig 7. The treated
fabric with UV absorber (1a-2a) and commercially available absorber (Rayson C Liquid) was

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subjected to xenotest for 12 hours. After exposition, UV absorber (1a-2a) and standard
produced reduction in its UPF properties little bit but it was almost same for designed and
commercially available UV absorber. The results of UV absorber (1a-2a) are very close to
the commercially available absorber (Rayson C Liquid) Fig 7.
It is clear that one of the most important characteristic of white cotton fabric is
retaining of their white colour during use. The synthesized UV absorbers did not decrease the
whiteness of fabric as much at 3% concentration but after exposition to light fastness testing
decrease its whiteness little bit as compared to standard but remain in good agreement with
the commercially available UV absorbers as shown in Fig 8. This behaviour may be due to
photo-destruction of residues of triazine.
It is clear from above discussion that both designed UV absorbers 1a and 2a have very good
light and washing fastness properties. We have compared their UPF properties with
commercially available UV absorbers and found that these can be used to enhance the UV
protection of cellulosic fabrics along with commercially available ones.
Conclusion
In search of viable UV protecting cotton fabric, two UV absorbers molecules (1a, 2a) are
designed and synthesized. Initially, electronic and optical properties of the designed
molecules are studied theoretically by employing density functional theory (DFT) and time
dependent density functional theory (TD-DFT). Theoretical determinations revealed that both
designed UV absorber molecules (1a, 2a) show absorption in UV region that is specific for
UV protectors. On the basis of these confirmations, these molecules were synthesized and
applied on the cellulosic fabric. The application of absorbers on cellulosic fabric indicated
that these compounds retained the good ultraviolet protective factor (UPF) which is
comparable with commercially available absorbers in market. Current study opened a new

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prospect for search of such molecules that will be persistent after laundry action and can be
utilized commercially.
Acknowledgements
This work is supported by department of Chemistry, University of Agriculture, Faisalabad,
Pakistan. The computations/simulations/[SIMILAR] were performed on resources provided
by the Swedish National Infrastructure for Computing (SNIC) at Umeå University, 901 87,
Umeå, Sweden.
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B. Mennucci, G. Petersson, Gaussian 09, Revision A. 02, Gaussian, Inc., Wallingford, CT, 200 (2009).
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disulfide-bis-ethylsulfone, Dyes and Pigments, 47 (2000) 151-167.

ACCEPTED MANUSCRIPT
Scheme and Figure Captions
Scheme 1: Synthetic route for UV absorbers (1a-2a)
Fig. 1: Schematic view of the HOMO, LUMO, HOMO-1 and LUMO+1 of absorber 1a and
2a at CAM-B3LYP/6-31G (d,p).
Fig. 2: Density of the state of the UV absorber 1a and 2a calculated with CAM-B3LYP/6-
31G (d,p).
Fig. 3: Experimental and theoretically calculated UV/Vis spectra of 1a and 2a with B3LYP,
CAM-B3LYP and WB97XD at 6-31G (d,p)
Fig. 4: Exhaustion % of absorbers (1a-2a) and rayosan C liquid on cotton fabric at different
% concentration
Fig. 5 Ultraviolet Protection Factor (UPF) of un-treated, treated fabric with 1a, 2a and
rayosan C liquid at different % concentration
Fig.6: Ultraviolet Protection Factor (UPF) of treated fabric (at 3% concentration) by absorber
(1a-2a) and rayosan C liquid after laundry action (10 times)
Fig. 7: UPF before and after 12 h exposure to Xenotest at 3% concentration of 1a, 2a and
rayosan C liquid.
Fig. 8: Whiteness Index (%) of un-treated, treated cotton fabric with 1a, 2a and rayosan C
liquid after UV light exposure at 3% concentration
Table 1: Theoretically calculated HOMO, LUMO, HOMO-1, LUMO+1 levels and energy
gaps for the absorber (1a and 2a) at 6-31G (d,p) basis set.
Table 2: The experimental and calculated λmax, excitation energies (ΔE), oscillator strength
(f) and electronic transition contribution calculated at 6-31G (d,p) basis set.
Table 3: Ultraviolet protection categories

ACCEPTED MANUSCRIPT
Cl
N
N
2
Cl
N
Cl
0-5oC
pH 3-3.5
NH2
NH2
HO3S
H2N
H2N
Cl
Cl
N
N
N
Cl
N
Cl
N
N
NH
HO3S
HN
HN
N
NH
N
N
Cl
N
N
N
Cl
Cl
II
Cl
I
NH2
2
35-40oC
pH 6-6.5
SO2
OSO3H
Cl
N
N
H
Cl
N
N
SO2
N
N
H
N
N
SO2
NH
NaO3SO
NaO3S
HN
NaO3SO
HN
N
NH
N
N
N
N
Cl
N
Cl
1a
2a
HN
SO2
HN
NaO3SO
SO2
NaO3SO
Scheme 1: Synthetic route for UV absorbers (1a-2a)

ACCEPTED MANUSCRIPT
Fig. 1: Schematic view of the HOMO, LUMO, HOMO-1 and LUMO+1 of absorber 1a and 2a at
CAM-B3LYP/6-31G (d,p).
Fig. 2: Density of the state of the UV absorber 1a and 2a calculated with CAM-B3LYP/6-31G (d,p).

ACCEPTED MANUSCRIPT
Fig. 3: Experimental and theoretically calculated UV/Vis spectra of 1a and 2a with B3LYP, CAM-
B3LYP and WB97XD at 6-31G (d,p)
1a
2a
100
Rayosan C Liquid
90
80
70
60
50
40
30
20
10
0
1
2
3
4
5
% Concentration
Fig. 4: Exhaustion % of absorbers (1a-2a) and rayosan C liquid on cotton fabric at different
% concentration

ACCEPTED MANUSCRIPT
1a
60
50
40
30
20
10
0
2a
Rayosan C Liquid
Untreated Fabric
1
2
3
4
5
% Concentration
Fig. 5 Ultraviolet Protection Factor (UPF) of un-treated, treated fabric with 1a, 2a and
rayosan C liquid at different % concentration
1a
2a
50
45
40
35
30
25
20
15
10
5
Rayosan C Liquid
Untreated Fabric
0
1
2
3
4
5
6
7
8
9
10
Washes
Fig.6: Ultraviolet Protection Factor (UPF) of treated fabric (at 3% concentration) by absorber
(1a-2a) and rayosan C liquid after laundry action (10 times)

ACCEPTED MANUSCRIPT
Before
After
50
45
40
35
30
25
20
15
10
5
0
1a
2a
Rayosan C Liquid Untreated Fabric
Treated Fabric
Fig. 7: UPF before and after 12 h exposure to Xenotest at 3% concentration of 1a, 2a and
rayosan C liquid.
1a
2a
120
Rayosan C Liquid
Untreated Fabric
100
80
60
40
20
0
0
6
12
Time in hours
Fig. 8: Whiteness Index (%) of un-treated, treated cotton fabric with 1a, 2a and rayosan C
liquid after UV light exposure at 3% concentration

ACCEPTED MANUSCRIPT
Table 1: Theoretically calculated HOMO, LUMO, HOMO-1, LUMO+1 levels and energy gaps for
the absorber (1a and 2a) at 6-31G (d,p) basis set.
HOMO
(eV)
LUMO
(eV)
E. Gap HOMO-1 LUMO+1 E.Gap
Functional
Absorber
(eV)
(eV)
8.48
(eV)
0.98
(eV)
7.91
1.13
6.78
7.49
CAM-B3LYP
B3LYP
6.60
8.52
2.47
0.57
7.06
9.06
2.25
0.45
4.12
7.95
4.80
8.61
1a
WB97XD
CAM-B3LYP
B3LYP
8.01
6.81
8.73
0.57
1.90
0.02
8.25
6.89
8.84
0.48
1.83
0.07
7.43
4.91
8.71
7.77
5.06
8.77
2a
WB97XD
Table 2: The experimental and calculated λmax, excitation energies (ΔE), oscillator strength
(f) and electronic transition contribution calculated at 6-31G (d,p) basis set.
Oscillator
strength
(ƒ)
Electronic
Transition
Contribution
Calc.
Exp.
λmax
(nm)
ΔE
(eV)
λmax
(nm)
Absorber
Functional
B3LYP
CAM-B3LYP
WB97XD
335.8
280.4
277
3.69
4.42
4.48
4.2
0.257
1.7936
1.741
H-0->L+0(+95%)
H-0->L+1(+61%)
H-0->L+1(+63%)
H-0->L+1(+89%)
292
292
292
282
282
282
1a
B3LYP
295.6
256.3
252.2
0.0218
0.4287
0.2218
H-0->L+2(+31%)
H-1->L+1(+24%)
H-2->L+1(+27%)
H-0->L+2(+19%)
CAM-B3LYP
WB97XD
4.84
4.92
2a
Table 3: Ultraviolet protection categories
Sr. No UPF Range
Protection Category
Excellent
1
2
3
40-50, 50 +
25-39
Very Good
Good
15-24

ACCEPTED MANUSCRIPT
Graphical abstract
O2S
OSO3Na
Cl
NH
2a
N
N
N
N
H2N
NH
O2S
N
Cl
NH
N
Cl
OSO3Na
II
Cl
N
NH2
HN
NH
N
HO3SO
HN
O2
S
N
N
N
N
H2N
5
Cl
N
Cl
.
Cl
3
2
-
N
N
C
3
o
Cl
5
H
-
5
Cl
.
p
0
C
6
o
O2S
-
0
2
Cl
6
4
N
N
-
OSO3Na
H
5
p
3
Cl
NH
N
H2N
Cl
N
N
I
NH
a
1
Cl
N
N
SO3H
NH2
SO3H
N
N
H
O2
S
Cl
NH
N
Cl
OS
O3N
a
N
N
N
N
N
H
H
SO3Na
Two triazine based Ultra Violet (UV) absorbers (1a, 2a) with different substituents were
designed and synthesized. The performance of synthesized compounds as UV absorbers and
their fastness properties were assessed by finishing the cotton fabric through exhaust method
at different concentration and results appeared in good range.

ACCEPTED MANUSCRIPT
Highlights:
 Two triazine based Ultra Violet (UV) absorbers with different substituents have been
designed computationally and synthesized.
 The application of absorbers on cellulosic fabric indicated that these compounds
retained the good ultraviolet protective factor (UPF) which is comparable with
commercially available absorbers in market.
 These molecules are anticipated to be persistent after laundry action and can be
utilized commercially.