Sulfone-infused covalent organic polymer derived from poly(2-aminothiophenol) and erythrosine B as an excellent tool for C

Abstract

The generation of a low HOMO-LUMO energy gap makes organic polymer-based composites an important class of materials with outstanding catalytic efficiency. The present work describes the simple and direct synthesis of an excellent photocatalyst, PC (C₂₆H₁₆NO₇S)_n via doping of erythrosine-B dye on sulfone infused poly(2-amino thiophenol) assembly (PA, (C₆H₄NO₂S)_n). The O 1 s spectrum displays peaks at 531.8 eV and 533.3 eV, representing the O=C and O–C groups of the in-situ generated fluorescein loaded on PA surface. Through absorption study (Tauc’s plot), the optical band gap (Eg) for polymer PA (2.9 eV) and photocatalyst PC (2.1 eV) has been calculated. Further, due to the efficient absorbance in the range of 400–600 nm with a low optical band gap, the applicability of the catalyst, PC has been checked in photocatalytic C–H activation in thiophene, and the generation of C–C bond with p-nitro aryldiazonium salt.

Keywords

Poly (2-amino thiophenol)sulfone erythrosine-B photocatalytic reaction C–H activation

1 Introduction

Energy is a basic necessity of human beings and we require a large amount of energy to meet our daily needs [1]. This relies upon energy sources whose existence is finite and will be depleted over time. So, it is crucial to shift towards renewable energy sources such as wind energy, hydro-energy, solar energy, etc [2]. Among all, works on solar energy is the prominent one. Many scientists are working on developing light-harvesting materials to produce green energy through sunlight [3, 4]. One of the most efficient and promising methods for converting solar energy into usable chemical energy is artificial photosynthesis/photo-catalysis, which involves chemical bond generation between molecules in the presence of light and catalyst. Light-harvesting materials play a crucial role as photocatalysts in a diverse range of natural transformations, including catalytic H₂ production [5], the reduction of CO₂ into valuable chemicals [6], sulfoxidation reactions, and the formation of C–C, C–N, and C–H bonds [7–8]. Fabrication of these light-harvesting materials relies on using various fluorescent dyes or conjugated systems as a starting component [9]. In mimicking natural photosynthesis, the presence of an antenna in a polymer, which is a chromophore efficiently absorbs sunlight across the solar spectrum and transmits the energy to the reaction center. As the reaction centers become excited, a photo-induced electron transfer occurs, giving rise to charge-separated states that effectively store electrochemical energy [10]. Doping dyes in the 1-D polymeric conjugated polymer can cause a lowering of the HOMO- LUMO band gap, which results in the efficient transfer of electrons [11].

Based on density functional theory (DFT) study, conductive polymeric material such as poly(1-naphthylamine), polythiophene, polyaniline, polyacetylene, polypyrrole, polycarbazole, or poly(o-phenylene diamine) have a low band gap and hence exhibit visible absorption activity. This makes them ideal for the range of light that semiconductors can absorb [12]. Scientists have noted that by polymerizing substituted anilines, the activity of polyaniline could be improved, which opens up new possibilities for its practical applications. Poly(2-aminothiophenol) is classified as an aniline-based conducting polymer and demonstrates unique optical and electrical properties, similar to polyaniline, due to π-electron delocalization along its polymer backbone. These unique characteristics make it an ideal choice in the field of materials science [12 –15]. Magnetic nanoparticles derived from poly (2-amino thiophenol) have been studied as a solid-phase extraction system for heavy metal ions, such as lead (II), copper (II), and silver (I) [16]. The use of dopant in these polymers makes it more interesting and useful in nano-composite chemistry. For example, Bhoomi et al. reported the synthesis of a poly (2-aminothiophenol)-silver (P₂ATPAg) nanocomposite using conductive and electro-active silver nanoparticles (AgNPs) [17]. Gopalan et al. [18] introduced a modified electrode by doping gold nanoparticles into a conductive polymer matrix of poly (4-aminothiophenol) while Nabid et al. synthesized modified MWCNTs (multiwall carbon nanotubes) using conducting poly (2-aminothiophenol) (MWCNTs/P2AT) nano-composites [19].

In the field of catalysis, gold nanoparticles doped poly(2-aminothiophenol) nanofibers have been observed as an interesting catalyst for the conversion of 4-nitrophenol to 4-aminohenol. In the morphology-dependent analysis, it has been observed that a large fiber diameter is more suitable than a low fiber diameter [20]. Poly(2-aminothiophenol)-stabilized gold nanoparticles has shown excellent catalytic activity to make a C–C bond on the reaction of aryl halides and aryl boronic acids in aerobic condition. The size of the gold as well as the thickness of the polymer is a crucial factor in making an efficient catalyst [21]. In the case, when the Pd-nanoparticles are doped in poly(o-aminothiophenol) results an efficient catalyst for Suzuki cross-coupling reactions to produce compounds of high importance [22]. In the literature, no report is available on doping any dye with poly(o-aminothiophenol) or its derivatives to produce a catalyst or photocatalyst. Herein, as per our current research interest in sulphur-chemistry [23], we have selected o-aminothiophenol as a starting material for the formation of poly (2-aminothiophenol) with sulfone (PA) functionality and further doped with erythrosine B as a dye to prepare photocatalyst, PC. As the literature says, the presence of sulfone functionality in any polymeric assembly improves the catalytic behavior drastically, so, we have checked the applicability of PC for photocatalytic C–H bond activation reaction [24].

2 Experimental section

2.1 Materials and methods

To perform experiments required chemicals such as 2-aminothiophenol, potassium iodide, iodine, and hydrogen peroxide solution (30%) have been purchased from Loba Chemie and used as received. Two solvents, DMS and ethyl acetate have been purchased from Loba Chemie and used in the experiment after dehydrating with known literature methods. For the ¹H NMR spectra, a Bruker Advance 500 MHz spectrometer has been used. IR data has been collected on a Perkin Elmer Spectrum IR Version 10.6.1 instrument. The photo-physical study (UV-Vis absorption study) has been performed on the UV-1900 UV-visible spectrophotometer by Shimadzu. An X-ray photoelectron spectroscopy (XPS) investigation has been carried out using a Kratos integrated imaging instrument (AXIS). Experiments have been performed at a 90° take-off angle, employing 300 W monochromatized Al Ka radiation. De-convolution of the data has been done using the VISION workstation software, assuming Gaussian peak shapes. The XRD analysis has been performed using an A D5000 diffractometer. The Shimatzu DTG-60H has been utilized to study the degradation process in terms of temperatures and corresponding weight loss percentages. The analysis has been conducted using a constant scan rate of 10 °C/min within a temperature range from ambient to 900 °C under N₂ atmospheres. Morphological studies have been performed on the JSM-IT500 model of JEOL.

2.2 Preparation and characterization

2.2.1 Synthesis of sulfone functionalized poly (2-amino thiophenol) (PA)

In a fully baked and dried round-bottomed flask, 500 mg (3.99 mmol) of 2-aminothiophenol is added to make a homogeneous solution in 10 ml of ethyl acetate at room temperature in an open environment. In this, 0.12 mL (3.99 mmol) of hydrogen peroxide (H₂O₂) and 6.6 mg (0.04 mmol) of potassium iodide (KI) are added and stirred for 4 hours (Scheme 1). A significant amount of black precipitate of sulfone functionalized poly (2-aminothiophenol) (PA) is obtained and purified by washing with ethyl acetate. Finally, the precipitate is dried at room temperature under vacuum. Yield = 48.7%.

Scheme 1

Synthesis of poly (2-aminothiophenol) with sulfone functionality (PA).

2.2.2 Synthesis of photocatalyst, (PC)

In a Teflon-lined hydrothermal autoclave reactor, 300 mg (1.9 mmol) of poly (2-aminothiophenol) (PA) and 3.3 g (3.82 mmol) of Erythrosine B are dissolved in 3 ml of dimethyl formamide (DMF). After that, the reaction mixture is heated at 210 °C for 8 hours (Scheme 2). As a result, a black-colour precipitate is formed, which is filtered and purified using the Soxhlet extraction method. Methanol is employed as the solvent during the extraction process to remove impurities. The obtained compound is referred to as PC (∼350 mg, ∼37%). The PC has been characterized through various techniques such as X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and UV-visible spectrophotometry.

Scheme 2

Synthesis of photocatalyst, (PC).

3 Results and discussion

3.1 XPS study

The XPS spectra of the polymer, PA are shown in Figure S1. In the C 1 s spectrum, a peak at 284.4 eV indicates the presence of C=C (sp²) bonds while in the N 1 s spectrum, the binding energies 399.1 eV correspond to pyridinic (–C=N–C) bonds. In the S 2p spectrum, two bands at 162.28 eV and 163.84 eV are attributed to the S–C (2p_1/2) and S–C (2p_3/2) entities. In addition to this, another band at the binding energy of 167.7 eV indicates the development of the –SO₂ (sulfone) group in the polymer [25]. These findings align with the previously reported literature. The XPS spectra of the photo-catalyst, PC have been presented in Fig. 1. The survey scan (Figure S2) shows the peak presence of carbon, sulfur, nitrogen, and oxygen. The C 1 s spectrum exhibits binding energy peaks at 284.5 eV, 285.6 eV, and 288.8 eV, corresponding to C=C (sp²), C–OH, and C(O)OH functionality, respectively. While, a binding energy peak at 399.3 eV in the N 1 s spectrum supports the stability of the imine bond (C=N–C) in PC as observed in the polymer, PA. The S 2p spectrum reveals two peaks at 162.28 eV and 163.81 eV, attributed to the presence of S–C covalent bonds (2p_1/2 and 2p_3/2). A suppressed peak at 167.7 eV indicates the presence of the –SO₂ (sulfone) group. The O 1 s spectrum displays peaks at 531.8 eV and 533.3 eV, representing the O=C and O–C groups of the in-situ generated fluorescein derivative, respectively [25]. The absence of I₂ in the atomic % analysis favors the removal of I- groups by H atoms. In a study, Barbano et. al. reported thermally induced release of iodine from Erythrosine B at higher temperatures during food processing [26]. The O/C ratio (ratio between the oxygen and carbon elements, as determined by the height of peaks) in PC is greater than the PA, supports the secondary interaction between H-atoms (ring-H & OH of ring as well as COOH groups) of in-situ generated fluorescein and O-atom (–SO₂ (sulfone) of polymer, PA [25]. The same trend was observed for the N-atom (–C=N–C) peak heights before and after loading of the in-situ generated fluorescein. These observations favor the presence of secondary interaction as well as loading of dye on PA for the generation of photocatalyst, PC.

Fig. 1

XPS spectra of photocatalyst, PC.

3.2 Infrared spectroscopy study

Infrared spectroscopy plays a crucial role in the analysis of present functional groups in polymers as well as composites that are either insoluble or have low solubility in common organic solvents. IR data of polymer, poly(2-amino thiophenol) (PA), and a composite (PC) has been recorded and a comparative study has been performed (Fig. 2). For PA, the infrared spectrum shows two prominent bands at 1139 cm^–1 and 1305 cm^–1, indicating the presence of a sulphone group [27] while bands at 1610 cm^–1 and 1019 cm^–1 correspond to the C=N and C–N groups, respectively. These findings suggest the formation of a ring system involving C=N–C and sulphone groups. In the case of PC, some new bands are observed along with some similar to those observed in PA. A novel peak at 1745 cm^–1 represents the presence of the carbonyl group of in situ generated fluorescein. According to the literature, the C=O peak in erythrosine B is observed at 1602 cm^–1, whereas in fluorescein, it emerges at 1727 cm^–1 [27]. This observation strongly suggests that an in situ transformation occurs in erythrosine B and leads to the formation of fluorescein. The in situ generated fluorescein interacts with polymer PA through secondary interactions (H-bonding and pi–pi interactions) leading to the formation of PC.

Fig. 2

IR spectra of PA and PC.

3.3 Thermo gravimetric analysis

The thermal stability of PA and PC has been examined by TGA. The TGA graph of polymer, PA (Figure S3) shows the decomposition process in two stages. In the first stage, between 30°C and 200°C, the removal of adsorbed/absorbed water takes place with a weight loss of 20.14% while in the second stage (200°C–900°C) the decomposition of the polymer skeleton takes place. The decomposition of photocatalyst (PC) follows closely the same pattern as that of PA and its decomposition also takes place in two steps (Fig. 3). In the first step, the removal of moisture takes place from 70° to 160°C [28]. In 2nd stage, the decomposition of skeletal polymer (PA) as well as of loaded fluorescein takes place in the temperature range of 160°C to above 800°C with ∼44% of residue left. The comparative study reveals that the photocatalyst PC is more stable than the polymer, PA.

Fig. 3

Thermo-gravimetric analysis of photocatalyst, (PC).

3.4 SEM (Scanning electron microscopy)

Scanning electron microscopy (SEM) study has been used to investigate the morphology (Fig. 4). The SEM micrographs are presented below, a) the polymer PA, and, b) the polymer PA after erythrosine B doping (photo-catalyst PC). The polymer PA exhibits the presence of particles ranging from 55 to 645 nm with varying lateral dimensions. The majority of the observed surfaces and edges appear smooth. The SEM image of photo-catalyst PC shows the presence of multiple layers might be attributed to intermolecular hydrogen bonding interactions between the in-situ generated fluorescein and with –SO₂ (sulfone) as well as –N=(imine) sites in the polymer chain [29].

Fig. 4

Morphology study of a) polymer (PA) and b) photo catalyst after doping with Erythrosine B (PC).

3.5 X-ray diffraction study

To study the nature of the compounds, X-ray diffraction studies of polymer PA and photocatalyst PC have been carried out. The PC exhibits two moderate-intensity peaks (Fig. 5) while the polymer PA shows a low-intensity peak (Figure S4). As per the literature report [30], a compound with a crystalline nature develops sharp peaks in XRD graphs, whereas in the case of an amorphous compound, generally very weak intensity peaks or broad/flat XRD graphs are observed. In the PC, the intensity of both peaks is not so strong, so it can be concluded that the PC falls under the category of low crystalline materials.

Fig. 5

XRD plot of photocatalyst (PC).

3.6 Absorption study

The optical properties of the polymeric structure of poly (2-aminothiophenol) (PA) and photocatalyst (PC) have been studied by UV-visible absorption spectroscopy. The absorption band of PA is observed at 600 nm (broad) while a strong resonance absorption peak appears at 530 nm for PC indicating the development of composites PC (Fig. 6). Tauc’s relation was utilized to determine the optical band gap of both the PA and the PC by analyzing their respective absorption spectra [31, 12b].

Fig. 6

Absorption spectra of poly (2-aminothiophenol) (PA) and photocatalyst (PC) (2 mg in 50 mL DMF).

$(ɛ h ν) = C (h ν - Eg) n$ (1)

In the Tauc relation (Equation 1), C is a constant, ɛ represents the molar extinction coefficient, Eg denotes the average band gap of the material, and the value of n depends on the type of transition. For the special case when n = Ɖ, Eg in equation (1) represents the direct allowed band gap. In our investigation of the average band gap, we utilized (ɛhν) ² versus hν plots, as depicted in both Figure S5 and Figure S6. By using this equation the optical band gap (Eg) for polymer PA (2.9 eV) and photocatalyst PC (2.1 eV) has been calculated. The optical band gap of PC (2.1 eV) is more suitable for photocatalytic activity. Therefore, only photocatalyst PC was selected for further investigation in the C–H bond activation.

3.7 Photocatalytic C–H bond activation

The photocatalytic activity of PC has been investigated in terms of the C–H bond activation by using p-nitro diazonium aryl salt and thiophene. The reaction of p-nitro diazonium aryl salt with thiophene generates a good yield of product. In the reaction, in a 5 ml reaction tube, p-nitro diazonium aryl salt (0.23 mmol) is taken in 1 ml DMSO. After this, 2.3 mmol thiophene, and 5 mg PC are added to the reaction tube and an inert atmosphere is maintained throughout the reaction period (Scheme 3). Afterward, the mixture is placed in the light reaction chamber (blue LED having a cut-off filter at 420 nm). The reaction progress is monitored by TLC and finally, the product is separated by diethyl ether/water (Yield: 95%). The final product has been characterized by using ¹H NMR and ¹³C NMR [31] (Figure S7, S8).

Scheme 3

The reaction of p-nitro diazonium aryl salt and thiophene.

Scheme 4

Photocatalytic reaction mechanism involving C–H bond activation.

For the optimization of the C–H bond activation reaction, different conditions have been explored (Table 1). In the study, 1 equivalent of p-nitro diazonium aryl salt (1a) with various equivalences of thiophene in the presence of 5 mg of PC in DMSO has been investigated. The ultimate optimization led to exceptional results by utilizing 10 equivalents of thiophene. Under these conditions, the reaction results in a remarkable 99.3% yield, with a conversion rate of 99.5% for the substrate [11b]. To ensure the significance of the newly designed photocatalyst and the influence of light, control experiments were performed. The outcomes of these experiments, along with the optimization results, are summarized in Table 1.

Table 1

The optimal reaction conditions for C–H bond activation

Sr. No	Optimization conditions	Yields (%)	Selectivity (%)
1	1 equivalent of thiophene, DMSO, 5 mg PC	22	25
2	10 equivalent of thiophene, DMSO, 5 mg PC	99.3	99.5
3	15 equivalent of thiophene, DMSO, 5 mg PC	91	94
4	15 equivalent of thiophene,, No PC, No light, 84 h	08	12
5	15 equivalent of thiophene, DMSO, 5 mg PC, No light, 84 h	18	24

3.8 Mechanistic aspects of C–H bond activation

In this mechanism, a photoredox photocatalyst (PC) plays a crucial role (Scheme 4). When exposed to solar light, PC gets excited to its singlet state, ¹PC*, and further stabilizes into a triplet state (³PC*) through the inter-state crossing, which is relatively more stable. The subsequent photocatalytic reaction proceeds through this triplet state (³PC*) via single electron transfer (SET) [11b , 33] and generates the aryl radical (1b) from p-substituted aryl diazonium salt. The reaction of the aryl radical (1b) with thiophene (2a) generates radical intermediate (2b) which further results in a carbocation intermediate (2c). The generation of carbocation intermediate is possible through two possible routes; (a) the oxidation of radical intermediate by PC radical cation, and (b) the oxidation of radical intermediate by p-substituted aryl diazonium salt in a radical chain transfer mechanism. Finally, the removal of hydrogen from intermediate 2c restores the aromaticity of system and facilitates the formation of the desired coupling product 3a.

4 Conclusion

A modified synthetic procedure has been used to synthesize sulfone-infused poly(2-aminothiophenol) (PA) by using potassium iodide (KI), and Hydrogen peroxide (H₂O₂) as a strong combination of oxidizing agents. The PA is further used to generate PC. This metal-free photocatalyst, PC shows excellent activity in C–H bond activation reaction and generation of compounds of high importance with superb yields and selectivity in DMSO. In future research endeavors, the reactivity of PA will be analyzed with other dyes as well as nano-metal oxides for the generation of more efficient photocatalysts.

Footnotes

Acknowledgments

We would like to express our sincere gratitude to the Council of Scientific & Industrial Research (CSIR) for providing a JRF fellowship to Renu Devi and SERB-DST (YSS/2015/001237) for their generous financial support. We would also like to extend our thanks to Manipal University for the SEM, XRD, and TGA facilities.

References

Jia

, Dai

, Wang

Refining energy sources in winemaking industry by using solar energy as alternatives for Fossil Fuels: A review and perspective, Renewable and Sustainable Energy Reviews 88 (2018), 278–296.

Renewable energy sources for developing countries, Solar Energy 30(4) (1983), 389.

Zhi-hua

et al. Recent progress in biomimetic light-harvesting materials, Acta Polymerica Sinica 012(10) (2012), 1108–1117.

Sinha Ray

Environmentally friendly polymer nanocomposites using polymer matrices from fossil fuel sources, Environmentally Friendly Polymer Nanocomposites (2013), 157–207.

Stathi

, Deligiannakis

, Louloudi

Co-catalytic enhancement of H2 production by Sio2 nanoparticles, , Catalysis Today 242 (2015), 146–152.

Albero

, García

Photocatalytic CO2 reduction, Green Chemistry and Sustainable Technology (2015), 1–31.

, Wang

, Jiang

Controllable sulfoxidation and sulfenylation with organic thiosulfate salts via dual electron- and energy-transfer photocatalysis, ACS Catalysis 7(11) (2017), 7587–7592.

Fagnoni

et al. Photocatalysis for the formation of the C–C bond, Chemical Reviews 107(6) (2007), 2725–2756. (b) X. Zhou, et al., Photocatalytic dehydrogenative C–C coupling of acetonitrile to succinonitrile, Nature Communications 13(1) (2022). (c)W.Wang, et al., Photocatalytic C–C coupling from carbon dioxide reduction on copper oxide with mixed-valence copper(I)/copper(II), Journal of the American Chemical Society 143(7) (2021), 2984–2993. (d) Y.-M. Lee, et al., Dioxygen activation by a Non-Heme Iron(II) complex: Formation of an iron(iv)–oxo complex via C–H activation by a putative iron(iii)–Superoxo species, Journal of the American Chemical Society 132(31) (2010), 10668–10670. (e) T.B. Boit, et al., Activation of C–O and C–N bonds using non-precious-metal catalysis, ACS Catalysis 10(20) (2020), 12109–12126.

Gong

et al. B-diketone boron difluoride dye-functionalized conjugated microporous polymers for efficient aerobic oxidative photocatalysis, Catalysis Science & Technology 11(11) (2021), 3905–3913.

10.

Llansola-Portoles

M.J.

et al. Artificial photosynthetic antennas and reaction centers, Comptes Rendus Chimie 20(3) (2017), 296–313.

11.

Mehta

S.K

, Kumar

, Chaudhary

, Bhasin

K.K.

Nucleation and growth of surfactant-passivated cds and HgS nanoparticles: Time-dependent absorption and luminescence profiles, Nanoscale 2(1) (2010), 145–152. b) C. Singh, et al., Flexible covalent porphyrin framework film: An emerged platform for photocatalytic C–H bond activation, 257 Applied Surface Science 544 (2021), 148938.

12.

Zoller

, Fabry

D.C.

, Rueping

Unexpected dual role of titanium dioxide in the visible light heterogeneous catalyzed C–H arylation of Heteroarenes, ACS Catalysis 5(6) (2010), 3900–3904. (b) D.P. Hari, P. Schroll and B. König, Metal-free, visible-light-mediated direct C–H arylation of heteroarenes with aryl diazonium salts, Journal of the American Chemical Society 134(6) (2012), 2958–2961. (c) J. Kappen, M. Skorupa and K. Krukiewicz, Conducting polymers as versatile tools for the electrochemical detection of cancer biomarkers, Biosensors 13(1) (2022), 31.

13.

Molapo

K.M.

et al. Electronics of conjugated polymers (I): Polyaniline, International Journal of Electrochemical Science 7(12) (2012), 11859–11875.

14.

Rahman

Md.

et al. Electrochemical sensors based on organic conjugated polymers, Sensors 8(1) (2008), 118–141.

15.

Azzam

E.M.

, Abd

H.M.

El-Salam and R.S. Aboad, Kinetic preparation and antibacterial activity of nanocrystalline poly(2-aminothiophenol), Polymer Bulletin 76(4) (2018), 1929–1947.

16.

Sedghi

et al. Application of magnetic nanoparticles modified with poly(2-amino thiophenol) as a sorbent for solid phase extraction and trace detection of lead, copper and silver ions in food matrices, RSC Advances 5(83) (2015), 67418–67426.

17.

Boomi

et al. Improved conductivity and antibacterial activity of poly(2-aminothiophenol)-silver nanocomposite against human pathogens, Journal of Photochemistry and Photobiology B: Biology 178 (2018)a, 323–329.

18.

Gopalan

A.I.

et al. Gold nanoparticles dispersed into poly(aminothiophenol) as a novel electrocatalyst— fabrication of modified electrode and evaluation of electrocatalytic activities for Dioxygen Reduction, Journal of Molecular Catalysis A: Chemical 256(1–2) (2006), 335–345.

19.

Nabid

M.R.

et al. Preparation and application of poly(2-amino thiophenol)/MWCNTs nanocomposite for adsorption and separation of cadmium and lead ions via solid phase extraction, Journal of Hazardous Materials 203–204 (2012), 93–100.

20.

Han

et al. Highly uniform self-assembled conducting polymer/gold fibrous nanocomposites: Additive-free controllable synthesis and application as efficient recyclable catalysts, Langmuir 27(20) (2011), 2181–2187.

21.

Han

, Liu

, Guo

Facile synthesis of highly stable gold nanoparticles and their unexpected excellent catalytic activity for suzuki–miyaura cross-coupling reaction in water, Journal of the American Chemical Society 131(6) (2009), 2060–2061.

22.

Chen

et al. Poly(O-aminothiophenol)-stabilized Pd nanoparticles as efficient heterogenous catalysts for Suzuki cross-coupling reactions, RSC Adv 7(74) (2017), 47104–47110.

23.

(a) A.P. Singh, et al., A novel, selective, and extremely responsive thienyl-based dual fluorogenic probe for tandem superoxide andHG2+chemosensing, Dalton Trans 42(10) (2013), 3285–3290. (b) A.P. Singh, et al., Extremely selective “turn-on” fluorescence detection of hypochlorite confirmed by proof-of-principle neurological studies via esterase action in living cells, The Analyst 138(10) (2013), 2829. (c)V.S. Rana, et al.,Anovel pyrene-based aggregation-induced enhanced emission active Schiff base fluorophore as a selective “turn-on” sensor for Sn2+ ions and its application in lung adenocarcinoma cells, Journal of Photochemistry and Photobiology A: Chemistry 436 (2023), 114409. (d) N. Sandhu, et al., X-Ray Crystallographic, Electrochemical, Quantum Chemical and Anti-Microbial Analysis of Fluorescein Based Schiff Base, Journal of Molecular Structure 1221 (2020), 128762. (f) S. Sehrawat, et al., Study of 5-Bromo-2-Thiophene Carboxaldehyde Derived Novel Schiff Base as a Biologically Active Agent as Well as X-Ray Crystallographic Study of C–S Coupled Benzothiazole, Journal of Molecular Structure 1269 (2022), 133782.

24.

a) Y. Luo, et al., Sulfone-modified covalent organic frameworks enabling efficient photocatalytic hydrogen peroxide generation via one-step two-electron O2 reduction, Angewandte Chemie International Edition 62(26) (2023). (b) X.Wang, et al., Sulfone-containing covalent organic frameworks for photocatalytic hydrogen evolution fromwater, Nature Chemistry 10(12) (2018), 1180–1189.

25.

(a)W.J. Van Ooij and A. Sabata, Characterization of films of organofunctional silanes by TOFSIMS and XPS, Journal of Adhesion Science and Technology 5(10) (1991), 843–863. (b) D. Yu. Osadchii, A.I. Olivos-Suarez, A.V. Bavykina and J. Gascon, Revisiting nitrogen species in covalent triazine frameworks, Langmuir 33(50) (2017), 14278–14285. (c) A. Munir, et al., Ultrasmall NI/NIO nanoclusters on thiol-functionalized and exfoliated graphene oxide nanosheets for durable oxygen evolution reaction, ACS Applied Energy Materials 2(1) (2018), 363–371. (d) E.A.M. Hassan, et al., Synergistic effect of hydrogen bonding and π–π stacking in interface of CF/Peek Composites, Composites Part B: Engineering 171 (2019), 70–77.

26.

Barbano

D.M.

, Dellavalle

M.E.

Thermal Degradation of FD & C Red No. 3 and Release of Free Iodide, J Food Prot 47(9) (1984), 668–669.

27.

(a)W.R. Feairheller and J.E. Katon, The vibrational spectra of Sulfones, Spectrochimica Acta 20(7) (1964), 1099–1108. (b) Table 5: Characteristic ir absorption frequencies of organic functional groups. doi:10.7717/peerj-matsci.4/table-5. (c) A.Y. Léon Bermúdez and R. Salazar, Synthesis and characterization of the polystyrene –313 asphaltene graft copolymer by Ft-IR Spectroscopy, CT&F –Ciencia, Tecnologya y Futuro 3(4) (2008), 157–167.

28.

Giroud

, Dorge

, Trouvé

Mechanism of thermal decomposition of a pesticide for safety concerns: Case of mancozeb, Journal of Hazardous Materials 184(1–3) (2010), 6–15.

29.

Zhang

et al. The effect of hydrogen bonding on self-assembled polyaniline nanostructures, Advanced Functional Materials 14(7) (2004), 693–698.

30.

Schreiner

, Jansen

, Ectors

, Volkmann

XRD analysis of phase development and peak broadening during the production of AAC, ce/papers 2(4) (2018), 117–120.

31.

(a) P. Makuła, M. Pacia and W. Macyk, How to correctly determine the band gap energy of modified semiconductor photocatalysts based on UV–vis spectra, The Journal of Physical Chemistry Letters 9(23) (2018), 6814–6817.

32.

Zoller

, Fabry

D.C.

, Rueping

Unexpected dual role of titanium dioxide in the visible light heterogeneous catalyzed C–H arylation of Heteroarenes, ACS Catalysis 5(6) (2015), 3900–3904.

33.

(a) S. Singh, et al., In situ prepared nrcpfs as highly active photo platforms for in situ bond formation between aryldiazonium salts and Heteroarenes, Photochemistry and Photobiology 98(4) (2022), 748–753. (b) R. Devi, et al., Synthesis of well-defined ester-linked covalent organic polymer and its potential applications in C–H bond activation, Journal of Photochemistry and Photobiology A: Chemistry 447 (2024), 115248.

Sulfone-infused covalent organic polymer derived from poly(2-aminothiophenol) and erythrosine B as an excellent tool for C–H activation

Abstract

Keywords

1 Introduction

2 Experimental section

2.1 Materials and methods

2.2 Preparation and characterization

2.2.1 Synthesis of sulfone functionalized poly (2-amino thiophenol) (PA)

3.1 XPS study

4 Conclusion

Footnotes

Acknowledgments

References