View Article Online View Journal
ChemComm Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: R. Gomes, P. Bhanja and A. Bhaumik, Chem. Commun., 2015, DOI: 10.1039/C5CC02147B.
This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.
www.rsc.org/chemcomm
Page 1 of 3
ChemComm View Article Online
DOI: 10.1039/C5CC02147B
Journal Name
RSCPublishing
Ruth Gomes, Piyali Bhanja and Asim Bhaumik*
A new triazine functionalized hexagonally or ordered covalent organic polymer (TRITER-1)) has been synthesized via Schiff Schiffbase condensation reaction between a tailor made tri triamine 1,3,5-tris-(4-aminophenyl)triazine (TAPT) and terephthaldehyde. This ordered porous polymer show showed high BET surface area (716 m2g-1) and excellent CO2 uptake capacity of 58.9 wt% at 273 K under 5 bar pressure. Functionalized microporous and mesoporous materials have been intensively investigated during the last few decades due to their exceptionally high BET surface area,, feasibility of grafting reactive functional groups at the pore surface and wide diversity of framework compositions.1 They found huge potential application applications in heterogeneous catalysis,2 sensing of metal-ions/mole lecules,3 selective gas adsorption,4 light-harvesting,5 drug-delivery6 and so on on. In this context, removal of the primary green house gas CO2 by means of physical adsorption or sequestration is very important for environmental remediation as the increased CO2 level in atmosphere is the major cause of climate change and global warming.7 Thus, design and synthesis of functionalized porous material materials having high porosity, BET surface area and large CO2 uptake capacity is an emerging field of research. During last one decade decade, metal organic frameworks (MOFs),8 porous co-ordination ation polymer polymers,9 porous 10 11 carbons , porous organic polymers (POPs) and covalent organic frameworks (COFs)12 have been extensively studied as gas storage material. Among these, the first two types of materials which are linked by co-ordination bonds are associated with major drawbacks due to their low stability and water-affinity, whereas for porous carbon, POP, COF etc, formed by strong covalent linkage linkages can overcome such drawback. The CO2 uptake capacity of these porous polymers can be enhanced by tuning the pore size,, BET surface area and incorporating nitrogen rich functionality in the framework.13 Recently, several porous organic polymers have been synthesized via polycondensation reaction between an di/tri di/triamine and an aromatic di/trianhydride and they showed high CO2 adsorption capacity.14,15 Wu et al. have reported a two-step step synthesis strategy of the imide functionalized 1,3,5-triazine triazine frameworks TPIs@IC, which showed CO2 uptake up to 3.2 mmol g-1 at 273 K/1 bar bar.14a Stegbauer et al. have reported the synthesis of a TFPT-COF COF by condensation of 1,3,5-tris-(4-formylphenyl)triazine formylphenyl)triazine and 2,5-diethoxyterephthalohydrazide.14b
Herein, we report for the first time the direct one-step one synthesis of 1,3,5-tris-(4-aminophenyl)triazine aminophenyl)triazine (TAPT) from 44 aminobenzonitrile via superacid catalyzed trimerization reaction and a new triazine functionalized covalent imine-based imine porous polymer TRITER-1, having 2D-hexagonal hexagonal mesophase using this designed organic scaffold under non-templating templating synthesis synthe pathway. The polymer TRITER-1 has been synthesized by reacting the monomers m TAPT and terephthaldehyde in a one-pot one polycondensation approach.
Figure 1. A) Schematic representation of synthesis of TRITER-1. TRITER B) Proposed structure of TRITER-1
ChemComm Accepted Manuscript
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
A triazine triazine-based covalent organic polymer for efficient CO2 adsorption
ChemComm
Page 2 of 3 View Article Online
In a typical synthesis, the Schiff-base covalent imine framework of TRITER-1 is formed by refluxing these monomers at 150 ºC in anhydrous dimethylformamide solvent for 12 h under inert atmosphere (Fig. 1A). The details of the experimental procedure are provided in the ESI Section S1. The CO2 adsorption behavior of the polymer is studied at two different temperatures to understand the nature of adsorbent-adsorbate adsorbate interactions and to measure the isosteric heat of adsorption. ray diffraction pattern of the The small-angle powder X-ray polymer TRITER-1 is shown in Fig. 2A,, suggesting that the material exhibits ordered 2D-hexagonal mesophase. phase. The material shows a strong diffraction peak at 2 value 2.95 associated ed with two weak intensity peaks at 2 value 4.97 and 5.88 corresponding to the reflection planes 100, 110 and 200 of the 2D-hexagonal hexagonal mesophase. The observed average d spacing (d100) is 2.99 nm following the Bragg’s equation (n =2dsin , where n=1 for 100 plane and =0.15406 nm). The wide angle PXRD pattern of the covalentorganic polymer gave semicrystaline crystaline feature of the material (ESI. ( Fig. S1). The physico-chemical chemical properties of TRITER-1 TRITER are listed in ESI. Table 1. The high resolution transmission electron microscopic image of TRITER-1 also confirms the hexagonal arrangement of the uniformly ordered supermicropores with an average pore width of ca. 1.52 nm (ESI. Fig. S2). 2). On the other hand, the scanning electron microscopic images shows self-assembled assembled spherical particles of average dimension 95 nm (ESI Fig. S3).. The N2 adsorption /desorption isotherm of the porous covalent-organic organic polymer follows mostly the type I pattern with some associated feature of type IV isotherm (Fig. 2B). ). Adsorption of large amount of N2 in the low pressure region (0-0.1 0.1 bar) indicates the presence of micropores in the framework. The Brunauer Emmett Teller (BET) surface area and pore volume of the polymer are 716 m2g-11 and 0.32 ccg-1, respectively. The pore size distribution (Fig 2B. inset) inse of TRITER-1 estimated employing the nonlocal onlocal density functional theory (NLDFT) using N2 at 77 K carbon on cylindrical pore model suggested the presence of supermicropores with pore dimension of ca. 1.7 nm. This result is also supported by the HR-TEM HR image analysis of the material. The stacking between the 2D-hexagonal 2D
Figure 2. A) Small angle PXRD pattern of TRITER-1. B) N2 adsorption/desorption isotherms of TRITER-1 at 77 K. Pore size distribution is shown in the inset.
Figure 3. 13C CP MAS NMR spectra of the polymer TRITER-1. TRITER
layers may not be perfectly of eclipsed AA type, which increases the wall thickness and decrease the pore width of the TRITER-1 material (ESI, Fig. S4) The idea about the chemical environment of different carbon atoms present in the polymeric network of TRITER1 is obtained from the 13C CP MAS NMR and Fourier transform infrared spectroscopic analysis. The 13C CP MAS NMR spectrum for the polymer is shown in Fig. 3, which exhibits strong resonance signals at 171, 158, 153, 136, 129,, 122 and 116 ppm, corresponding to carbons at different chemical environment as shown in the framework structure of Fig. 3 (inset).. The formation of the triazine ring is confirmed from the signal at 171 ppm, whereas the peak p at 158 ppm confirms the formation of the imine bond. The peaks at 136, 129, 122 and 116 ppm originated from aromatic carbons at different chemical environment of the benzene ring. ring TAPT has been characterized by 1H, 13C NMR and Mass spectroscopy (ESI. Fig. S57) and this 13C CP MAS NMR data also closely matches with these 13 C signals. The absence of peak at ~ 190 ppm for the –CHO group of the precursor terephthaldehyde confirms the absence of any unreacted aldehyde group in TRITER-1.. Also, the absence of peak in the aliphatic region eliminates the idea of any tertiary tertia carbon being formed.15a FT-IR spectrum of TRITER-1 TRITER showed two distinct additional peaks at 1700 cm-1 and 1202 cm-1 as compared to that of the reactant amine TAPT, which can be assigned as the characteristic C=N stretching of imine (ESI. Fig. S8)). On the other hand, IR spectrum of TAPT monomer shows strong adsorption bands at 1503 cm-1 and 1360 cm-1 suggesting ting the successful formation of triazine ring. In addition, absence of absorption around 2235 cm-1 confirms no -C N group of the precursor 4-aminobenzonitrile aminobenzonitrile moiety being present in TRITER-1. The FT-IR IR spectrum of terephthaldehyde shows the aldehyde stretching at 1692 cm-11. The UV-Vis absorbance spectrum (ESI. Fig. S9) of TRITER-1 1 shows absorbance maxima at * 425 nm corresponding to the transition of the N-containing N conjugated aromatic system. The band gap energy estimated from this UV-Vis spectrum is 2.5 eV. Thermogravimetric hermogravimetric analysis (ESI. Fig. S10) of TRITER-1 suggests that the material is highly stable. The DTA profile shows the first major weight loss at 400 ºC. The C, H and N contents of TRITER-1 1 obtained from elemental analysis are C=78.67%, H=3.99% and N=16.03%, which agrees well with the theoretically calculated elemental analysis result (ESI, Table 2). Fig. 4 shows the CO2 adsorption isotherm of the covalent organic polymer TRITER-1 1 at 273 K and at 298 K up to 5 bar pressure. The isotherm shows hows gradually enhanced uptake of CO2 with increasing pressure of the adsorbate. The polymer shows a maximum uptake of 13.38 mmolg-1 (i.e.. 58.9 wt%) at 273 K and3.11 mmolg-1 ( i.e 13.7 wt %) at 298 K under 5 bar pressure. Such high uptake of Lewis acid CO2 can be attributed to the high BET surface
ChemComm Accepted Manuscript
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
DOI: 10.1039/C5CC02147B
Page 3 of 3
ChemComm View Article Online
3
4 5
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
6 7
Figure 4. CO2 adsorption/desorption isotherm of TRITER-1 at 273K and 298K.
area of the polymer, supermicroporosity and the presence of nitrogen rich basic 1,3,5-triazine ring and imine functionality. The isosteric heat of adsorption (Qst) for TRITER-1 is calculated using ClausiusClapeyron equation and plotted as a function of the volume of CO2 adsorbed (ESI. Fig. S11). The high initial Qst value (38.1 kJmol-1) indicates strong adsorbate-adorbent interaction of the CO2 molecules with the polymeric framework.16 Also the isotherms showed reversible nature, suggesting that the material could liberate the adsorbed CO2 molecules without applying any external thermal energy. Further, the porous polymer has been recycled for four consecutive CO2 adsorption cycles and it is found that the uptake capacity reduce only by 3.24% after the fourth cycle (ESI. Fig. S12), suggesting future potential of TRITER-1 as an adsorbent.
Conclusions
In conclusion, we have reported the one-step synthesis of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) by trimerization of 4aminobenzonitrile. Schiff base polycondensation of TAPT with terephthaldehyde resulted a new high surface area, supermicroporous (pore size 1.5 nm) and N-rich (16.03%) covalent organic polymer TRITER-1. The material exhibits 2D-hexagonal mesophase in small angle PXRD. The high surface area and N-rich covalent organic framework material TRITER-1 showed very high CO2 uptake capacity of 58.9 wt% at 273 K and 13.7 wt% at 298 K up under 5 bar pressure. Very high CO2 uptake reported herein for TRITER-1 may motivate the researchers to design novel N-rich covalent organic polymers, which could open new avenues in environmental clean-up.
8
9
10
11
12
13
Acknowledgements
RG and PB thank CSIR, New Delhi for respective senior and junior research fellowship. AB wishes to thank DST, New Delhi for DST-SERB and DST-UKIERI project grants.
14
Notes and references
Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur 700 032, India, *Corresponding author. E-mail: [email protected] Electronic Supplementary Information (ESI) available: Experimental and characterization data of the covalent organic polymer, 1H and 13C NMR data of TAPT, Qst, recyclability test. For details please see DOI: 10.1039/c000000x/ 1 (a) Y. H. Xu, S. B. Jin, H. Xu, A. Nagai and D. L. Jiang, Chem. Soc. Rev., 2013, 42, 8012; (b) B. J. Smith, W. R. Dichtel, J. Am. Chem. Soc., 2014, 136, 8783; (c) W. M. Xuan, C. C. Ye, M. N. Zhang, Z. J. Chen and Y. Cui, Chem. Sci., 2013, 4, 3154; (d) E. Merino, E. Verde-Sesto, E. M. Maya, M. Iglesias, F. Sanchez and A. Corma, Chem. Mater., 2013, 25, 981. 2 (a) P. Borah, X. K. T. Nguyen and Y. L. Zhao, Angew. Chem. Int. Ed., 2012, 51, 7756; (b) S. Bhunia, B. Banerjee and A Bhaumik, Chem.
15
16
Commun., 2015, 51, 5020; (c) M. Rose, ChemCatChem, 2014, 6, 1166; (d) P. Puthiaraj and K. Pitchumani, Green Chem., 2014, 16, 4223. (a) K. Sarkar, K. Dhara, M. Nandi, P. Roy, A. Bhaumik and P. Banerjee, Adv. Funct. Mater., 2009, 19, 223; (b) L. Hou, C. L. Zhu, X. P. Wu, G. N. Chen and D. P. Tang, Chem. Commun., 2014, 50, 1441; (c) T. A. Fayed, M. H. Shaaban, M. N. El-Nahass and F. M. Hassan, Microporous Mesoporous Mater., 2014, 198, 144. (a) J. Yu and P. B. Balbuena, J. Phys. Chem. C, 2013, 117, 3383; (b) A. P. Katsoulidis, S. M. Dyar, R. Carmieli, C. D. Malliakas, M. R. Wasielewski and M. G. Kanatzidis, J. Mater. Chem. A., 2013, 1, 10465. H. Takeda, M. Ohashi, Y. Goto, T. Ohsuna, T. Tani and S. Inagaki, Chem. Eur. J., 2014, 20, 9130. H. Y. Lian, M. Hu, C. H. Liu, Y. Yamauchi and K. C. –W. Wu, Chem. Commun., 2012, 48, 5151. (a) N. Stern, Stern Review on the Economics of Climate Change, Cambridge University Press, Cambridge,2006; (b) R. K. Pachauri and A. Reisinger, IPCC Fourth Assessment Report, Intergovernmental Panel on Climate Change, 2007; (c) P. Nugent, Y. Belmabkhout, S. D. Burd, A. J. Cairns, R. Luebke, K. Forrest, T. Pham, S. Q. Ma, B. Space, L. Wojtas, M. Eddaoudi and M. J. Zaworotko, Nature, 2013, 495, 80. (a) J. Liu, P. K. Thallapally, B. P. McGrail, D. R. Brown and J. Liu, Chem. Soc. Rev., 2012, 41, 2308; (b) S. Hasegawa, S. Horike, R. Matsuda, S. Furukawa, K. Mochizuki, Y. Kinoshita and S. Kitagawa, J. Am. Chem. Soc., 2007, 129, 2607; (c) T. M. McDonald, W. R. Lee, J. A. Mason, B. M. Wiers, C. S. Hong and J. R. Long, J. Am. Chem. Soc., 2012, 134, 7056. (a) S. Noro, J. Mizutani, Y. Hijikata, R. Matsuda, H. Sato, S. Kitagawa, K. Sugimoto, Y. Inubushi, K. Kubo and T. Nakamura . Nat. Commun., 2015, 6:5851 doi: 10.1038/ncomms6851; (b) P. Li, Y.-B. He, J. Guang, L.-H. Weng, J. C.-G. Zhao, S. C. Xiang and B. L. Chen, J. Am. Chem. Soc., 2014, 136, 547. (a) M. Nandi, K. Okada, A. Dutta, A. Bhaumik, J. Maruyama, D. Derksa and H. Uyama, Chem. Commun., 2012, 48, 10283; (b) B. Ashourirad, A. K. Sekizkardes, S. Altarawneh and H. M. El-Kaderi, Chem. Mater., 2015, 27, 1349; (a) X. Zhu, S. M. Mahurin, S-H An, C-L Do-Thanh, C. Tian, Y. Li, L. W. Gill, E. W. Hagaman, Z. Bian, J-H Zhou, J. Hu, H. Liu and S. Dai Chem. Commun., 2014, 50, 7933; (b) A. Modak, M. Pramanik, S. Inagaki and A. Bhaumik, J. Mater. Chem. A, 2014, 2, 11642; (c) J. Wang, S. Xu, Y. Wang, R. Cai, C. Lv, W. Qiao, D. Long and L. Linga, RSC Adv., 2014, 4, 16224; (d) R. Gomes and A. Bhaumik, J. Solid. State. Chem., 2015, 222, 7; (e) P. Arab, M. G. Rabbani, A. K. Sekizkardes, T. Islamoglu and H. M. El-Kaderi, Chem. Mater., 2014, 26, 1385. (a) F. J. Uribe-Romo, J. R. Hunt, H. Furukawa, C. Klock, M. O’ Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 4570; (b) M. G. Rabbani, A. K. Sekizkardes, Z. Kahveci, T. E. Reich, R. Ding and H. M. El-Kaderi, Chem. Eur. J., 2013, 19, 3324; (c) Y. J. Choi, J. H. Choi, K. M. Choi and J. K. Kang, J. Mater. Chem., 2011, 21, 1073. (a) R. Luebke, J. F. Eubank, A. J. Cairns, Y. Belmabkhout, L. Wojtas and M. Eddaoudi, Chem. Commun. 2012, 48, 1455; (b) J. S. Qin, D. Y. Du, W. L. Li, J. P. Zhang, S. L. Li, Z. M. Su, X. L. Wang, Q. Xu, K. Z. Shao and Y. Q. Lan, Chem. Sci., 2012, 3, 2114; (c) K. Liu, B. Y. Li, Y. Li, X. Li, F. Yang, G. Zeng, Y. Peng, Z. J. Zhang, G. H. Li, Z. Shi, S. H. Feng and D. T. Song, Chem. Commun., 2014, 50, 5031. (a) S. Wu, S. Gu, A. Zhang, G. Yu, Z. Wang, J. Jianc and C. Pan, J. Mater. Chem. A, 2015, 3, 878; (b) L. Stegbauer, K. Schwinghammer and B. V. Lotsch, Chem. Sci., 2014, 5, 2789; (c) S. Chandra, S. Kandambeth, B. P. Biswal, B. Lukose, S. M. Kunjir, M. Chaudhary, R. Babarao, T. Heine and R. Banerjee, J. Am. Chem. Soc., 2013, 135, 17853; (d) M. K. Bhunia, S. K. Das, P. Pachfule, R. Banerjee and A. Bhaumik, Dalton Trans., 2012, 41, 1304. (a) M. G. Schwab, B. Fassbender, H. W. Spiess, A. Thomas, X. Feng, and K. Mullen, J. Am. Chem. Soc. 2009, 131, 7216; (b) H. A. Patel, F. Karadas, J. Byun, J. Park, E. Deniz, A. Canlier, Y. Jung, M. Atilhan and C. T. Yavuz, Adv. Funct. Mater., 2013, 23, 2270; (c) H. Furukawa and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 8875; (d) S. Hug, M. B. Mesch, H. Oh, N. Popp, M. Hirscher, J. Senkerd and B. V. Lotsch, J. Mater. Chem. A, 2014, 2, 5928. S. T. Yang, J. Y. Kim, J. Kim and W. S. Ahn, Fuel, 2012, 97, 235.
ChemComm Accepted Manuscript
DOI: 10.1039/C5CC02147B
ChemComm Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: R. Gomes, P. Bhanja and A. Bhaumik, Chem. Commun., 2015, DOI: 10.1039/C5CC02147B.
This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.
www.rsc.org/chemcomm
Page 1 of 3
ChemComm View Article Online
DOI: 10.1039/C5CC02147B
Journal Name
RSCPublishing
Ruth Gomes, Piyali Bhanja and Asim Bhaumik*
A new triazine functionalized hexagonally or ordered covalent organic polymer (TRITER-1)) has been synthesized via Schiff Schiffbase condensation reaction between a tailor made tri triamine 1,3,5-tris-(4-aminophenyl)triazine (TAPT) and terephthaldehyde. This ordered porous polymer show showed high BET surface area (716 m2g-1) and excellent CO2 uptake capacity of 58.9 wt% at 273 K under 5 bar pressure. Functionalized microporous and mesoporous materials have been intensively investigated during the last few decades due to their exceptionally high BET surface area,, feasibility of grafting reactive functional groups at the pore surface and wide diversity of framework compositions.1 They found huge potential application applications in heterogeneous catalysis,2 sensing of metal-ions/mole lecules,3 selective gas adsorption,4 light-harvesting,5 drug-delivery6 and so on on. In this context, removal of the primary green house gas CO2 by means of physical adsorption or sequestration is very important for environmental remediation as the increased CO2 level in atmosphere is the major cause of climate change and global warming.7 Thus, design and synthesis of functionalized porous material materials having high porosity, BET surface area and large CO2 uptake capacity is an emerging field of research. During last one decade decade, metal organic frameworks (MOFs),8 porous co-ordination ation polymer polymers,9 porous 10 11 carbons , porous organic polymers (POPs) and covalent organic frameworks (COFs)12 have been extensively studied as gas storage material. Among these, the first two types of materials which are linked by co-ordination bonds are associated with major drawbacks due to their low stability and water-affinity, whereas for porous carbon, POP, COF etc, formed by strong covalent linkage linkages can overcome such drawback. The CO2 uptake capacity of these porous polymers can be enhanced by tuning the pore size,, BET surface area and incorporating nitrogen rich functionality in the framework.13 Recently, several porous organic polymers have been synthesized via polycondensation reaction between an di/tri di/triamine and an aromatic di/trianhydride and they showed high CO2 adsorption capacity.14,15 Wu et al. have reported a two-step step synthesis strategy of the imide functionalized 1,3,5-triazine triazine frameworks TPIs@IC, which showed CO2 uptake up to 3.2 mmol g-1 at 273 K/1 bar bar.14a Stegbauer et al. have reported the synthesis of a TFPT-COF COF by condensation of 1,3,5-tris-(4-formylphenyl)triazine formylphenyl)triazine and 2,5-diethoxyterephthalohydrazide.14b
Herein, we report for the first time the direct one-step one synthesis of 1,3,5-tris-(4-aminophenyl)triazine aminophenyl)triazine (TAPT) from 44 aminobenzonitrile via superacid catalyzed trimerization reaction and a new triazine functionalized covalent imine-based imine porous polymer TRITER-1, having 2D-hexagonal hexagonal mesophase using this designed organic scaffold under non-templating templating synthesis synthe pathway. The polymer TRITER-1 has been synthesized by reacting the monomers m TAPT and terephthaldehyde in a one-pot one polycondensation approach.
Figure 1. A) Schematic representation of synthesis of TRITER-1. TRITER B) Proposed structure of TRITER-1
ChemComm Accepted Manuscript
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
A triazine triazine-based covalent organic polymer for efficient CO2 adsorption
ChemComm
Page 2 of 3 View Article Online
In a typical synthesis, the Schiff-base covalent imine framework of TRITER-1 is formed by refluxing these monomers at 150 ºC in anhydrous dimethylformamide solvent for 12 h under inert atmosphere (Fig. 1A). The details of the experimental procedure are provided in the ESI Section S1. The CO2 adsorption behavior of the polymer is studied at two different temperatures to understand the nature of adsorbent-adsorbate adsorbate interactions and to measure the isosteric heat of adsorption. ray diffraction pattern of the The small-angle powder X-ray polymer TRITER-1 is shown in Fig. 2A,, suggesting that the material exhibits ordered 2D-hexagonal mesophase. phase. The material shows a strong diffraction peak at 2 value 2.95 associated ed with two weak intensity peaks at 2 value 4.97 and 5.88 corresponding to the reflection planes 100, 110 and 200 of the 2D-hexagonal hexagonal mesophase. The observed average d spacing (d100) is 2.99 nm following the Bragg’s equation (n =2dsin , where n=1 for 100 plane and =0.15406 nm). The wide angle PXRD pattern of the covalentorganic polymer gave semicrystaline crystaline feature of the material (ESI. ( Fig. S1). The physico-chemical chemical properties of TRITER-1 TRITER are listed in ESI. Table 1. The high resolution transmission electron microscopic image of TRITER-1 also confirms the hexagonal arrangement of the uniformly ordered supermicropores with an average pore width of ca. 1.52 nm (ESI. Fig. S2). 2). On the other hand, the scanning electron microscopic images shows self-assembled assembled spherical particles of average dimension 95 nm (ESI Fig. S3).. The N2 adsorption /desorption isotherm of the porous covalent-organic organic polymer follows mostly the type I pattern with some associated feature of type IV isotherm (Fig. 2B). ). Adsorption of large amount of N2 in the low pressure region (0-0.1 0.1 bar) indicates the presence of micropores in the framework. The Brunauer Emmett Teller (BET) surface area and pore volume of the polymer are 716 m2g-11 and 0.32 ccg-1, respectively. The pore size distribution (Fig 2B. inset) inse of TRITER-1 estimated employing the nonlocal onlocal density functional theory (NLDFT) using N2 at 77 K carbon on cylindrical pore model suggested the presence of supermicropores with pore dimension of ca. 1.7 nm. This result is also supported by the HR-TEM HR image analysis of the material. The stacking between the 2D-hexagonal 2D
Figure 2. A) Small angle PXRD pattern of TRITER-1. B) N2 adsorption/desorption isotherms of TRITER-1 at 77 K. Pore size distribution is shown in the inset.
Figure 3. 13C CP MAS NMR spectra of the polymer TRITER-1. TRITER
layers may not be perfectly of eclipsed AA type, which increases the wall thickness and decrease the pore width of the TRITER-1 material (ESI, Fig. S4) The idea about the chemical environment of different carbon atoms present in the polymeric network of TRITER1 is obtained from the 13C CP MAS NMR and Fourier transform infrared spectroscopic analysis. The 13C CP MAS NMR spectrum for the polymer is shown in Fig. 3, which exhibits strong resonance signals at 171, 158, 153, 136, 129,, 122 and 116 ppm, corresponding to carbons at different chemical environment as shown in the framework structure of Fig. 3 (inset).. The formation of the triazine ring is confirmed from the signal at 171 ppm, whereas the peak p at 158 ppm confirms the formation of the imine bond. The peaks at 136, 129, 122 and 116 ppm originated from aromatic carbons at different chemical environment of the benzene ring. ring TAPT has been characterized by 1H, 13C NMR and Mass spectroscopy (ESI. Fig. S57) and this 13C CP MAS NMR data also closely matches with these 13 C signals. The absence of peak at ~ 190 ppm for the –CHO group of the precursor terephthaldehyde confirms the absence of any unreacted aldehyde group in TRITER-1.. Also, the absence of peak in the aliphatic region eliminates the idea of any tertiary tertia carbon being formed.15a FT-IR spectrum of TRITER-1 TRITER showed two distinct additional peaks at 1700 cm-1 and 1202 cm-1 as compared to that of the reactant amine TAPT, which can be assigned as the characteristic C=N stretching of imine (ESI. Fig. S8)). On the other hand, IR spectrum of TAPT monomer shows strong adsorption bands at 1503 cm-1 and 1360 cm-1 suggesting ting the successful formation of triazine ring. In addition, absence of absorption around 2235 cm-1 confirms no -C N group of the precursor 4-aminobenzonitrile aminobenzonitrile moiety being present in TRITER-1. The FT-IR IR spectrum of terephthaldehyde shows the aldehyde stretching at 1692 cm-11. The UV-Vis absorbance spectrum (ESI. Fig. S9) of TRITER-1 1 shows absorbance maxima at * 425 nm corresponding to the transition of the N-containing N conjugated aromatic system. The band gap energy estimated from this UV-Vis spectrum is 2.5 eV. Thermogravimetric hermogravimetric analysis (ESI. Fig. S10) of TRITER-1 suggests that the material is highly stable. The DTA profile shows the first major weight loss at 400 ºC. The C, H and N contents of TRITER-1 1 obtained from elemental analysis are C=78.67%, H=3.99% and N=16.03%, which agrees well with the theoretically calculated elemental analysis result (ESI, Table 2). Fig. 4 shows the CO2 adsorption isotherm of the covalent organic polymer TRITER-1 1 at 273 K and at 298 K up to 5 bar pressure. The isotherm shows hows gradually enhanced uptake of CO2 with increasing pressure of the adsorbate. The polymer shows a maximum uptake of 13.38 mmolg-1 (i.e.. 58.9 wt%) at 273 K and3.11 mmolg-1 ( i.e 13.7 wt %) at 298 K under 5 bar pressure. Such high uptake of Lewis acid CO2 can be attributed to the high BET surface
ChemComm Accepted Manuscript
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
DOI: 10.1039/C5CC02147B
Page 3 of 3
ChemComm View Article Online
3
4 5
Published on 13 May 2015. Downloaded by University of Connecticut on 14/05/2015 10:41:03.
6 7
Figure 4. CO2 adsorption/desorption isotherm of TRITER-1 at 273K and 298K.
area of the polymer, supermicroporosity and the presence of nitrogen rich basic 1,3,5-triazine ring and imine functionality. The isosteric heat of adsorption (Qst) for TRITER-1 is calculated using ClausiusClapeyron equation and plotted as a function of the volume of CO2 adsorbed (ESI. Fig. S11). The high initial Qst value (38.1 kJmol-1) indicates strong adsorbate-adorbent interaction of the CO2 molecules with the polymeric framework.16 Also the isotherms showed reversible nature, suggesting that the material could liberate the adsorbed CO2 molecules without applying any external thermal energy. Further, the porous polymer has been recycled for four consecutive CO2 adsorption cycles and it is found that the uptake capacity reduce only by 3.24% after the fourth cycle (ESI. Fig. S12), suggesting future potential of TRITER-1 as an adsorbent.
Conclusions
In conclusion, we have reported the one-step synthesis of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) by trimerization of 4aminobenzonitrile. Schiff base polycondensation of TAPT with terephthaldehyde resulted a new high surface area, supermicroporous (pore size 1.5 nm) and N-rich (16.03%) covalent organic polymer TRITER-1. The material exhibits 2D-hexagonal mesophase in small angle PXRD. The high surface area and N-rich covalent organic framework material TRITER-1 showed very high CO2 uptake capacity of 58.9 wt% at 273 K and 13.7 wt% at 298 K up under 5 bar pressure. Very high CO2 uptake reported herein for TRITER-1 may motivate the researchers to design novel N-rich covalent organic polymers, which could open new avenues in environmental clean-up.
8
9
10
11
12
13
Acknowledgements
RG and PB thank CSIR, New Delhi for respective senior and junior research fellowship. AB wishes to thank DST, New Delhi for DST-SERB and DST-UKIERI project grants.
14
Notes and references
Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur 700 032, India, *Corresponding author. E-mail: [email protected] Electronic Supplementary Information (ESI) available: Experimental and characterization data of the covalent organic polymer, 1H and 13C NMR data of TAPT, Qst, recyclability test. For details please see DOI: 10.1039/c000000x/ 1 (a) Y. H. Xu, S. B. Jin, H. Xu, A. Nagai and D. L. Jiang, Chem. Soc. Rev., 2013, 42, 8012; (b) B. J. Smith, W. R. Dichtel, J. Am. Chem. Soc., 2014, 136, 8783; (c) W. M. Xuan, C. C. Ye, M. N. Zhang, Z. J. Chen and Y. Cui, Chem. Sci., 2013, 4, 3154; (d) E. Merino, E. Verde-Sesto, E. M. Maya, M. Iglesias, F. Sanchez and A. Corma, Chem. Mater., 2013, 25, 981. 2 (a) P. Borah, X. K. T. Nguyen and Y. L. Zhao, Angew. Chem. Int. Ed., 2012, 51, 7756; (b) S. Bhunia, B. Banerjee and A Bhaumik, Chem.
15
16
Commun., 2015, 51, 5020; (c) M. Rose, ChemCatChem, 2014, 6, 1166; (d) P. Puthiaraj and K. Pitchumani, Green Chem., 2014, 16, 4223. (a) K. Sarkar, K. Dhara, M. Nandi, P. Roy, A. Bhaumik and P. Banerjee, Adv. Funct. Mater., 2009, 19, 223; (b) L. Hou, C. L. Zhu, X. P. Wu, G. N. Chen and D. P. Tang, Chem. Commun., 2014, 50, 1441; (c) T. A. Fayed, M. H. Shaaban, M. N. El-Nahass and F. M. Hassan, Microporous Mesoporous Mater., 2014, 198, 144. (a) J. Yu and P. B. Balbuena, J. Phys. Chem. C, 2013, 117, 3383; (b) A. P. Katsoulidis, S. M. Dyar, R. Carmieli, C. D. Malliakas, M. R. Wasielewski and M. G. Kanatzidis, J. Mater. Chem. A., 2013, 1, 10465. H. Takeda, M. Ohashi, Y. Goto, T. Ohsuna, T. Tani and S. Inagaki, Chem. Eur. J., 2014, 20, 9130. H. Y. Lian, M. Hu, C. H. Liu, Y. Yamauchi and K. C. –W. Wu, Chem. Commun., 2012, 48, 5151. (a) N. Stern, Stern Review on the Economics of Climate Change, Cambridge University Press, Cambridge,2006; (b) R. K. Pachauri and A. Reisinger, IPCC Fourth Assessment Report, Intergovernmental Panel on Climate Change, 2007; (c) P. Nugent, Y. Belmabkhout, S. D. Burd, A. J. Cairns, R. Luebke, K. Forrest, T. Pham, S. Q. Ma, B. Space, L. Wojtas, M. Eddaoudi and M. J. Zaworotko, Nature, 2013, 495, 80. (a) J. Liu, P. K. Thallapally, B. P. McGrail, D. R. Brown and J. Liu, Chem. Soc. Rev., 2012, 41, 2308; (b) S. Hasegawa, S. Horike, R. Matsuda, S. Furukawa, K. Mochizuki, Y. Kinoshita and S. Kitagawa, J. Am. Chem. Soc., 2007, 129, 2607; (c) T. M. McDonald, W. R. Lee, J. A. Mason, B. M. Wiers, C. S. Hong and J. R. Long, J. Am. Chem. Soc., 2012, 134, 7056. (a) S. Noro, J. Mizutani, Y. Hijikata, R. Matsuda, H. Sato, S. Kitagawa, K. Sugimoto, Y. Inubushi, K. Kubo and T. Nakamura . Nat. Commun., 2015, 6:5851 doi: 10.1038/ncomms6851; (b) P. Li, Y.-B. He, J. Guang, L.-H. Weng, J. C.-G. Zhao, S. C. Xiang and B. L. Chen, J. Am. Chem. Soc., 2014, 136, 547. (a) M. Nandi, K. Okada, A. Dutta, A. Bhaumik, J. Maruyama, D. Derksa and H. Uyama, Chem. Commun., 2012, 48, 10283; (b) B. Ashourirad, A. K. Sekizkardes, S. Altarawneh and H. M. El-Kaderi, Chem. Mater., 2015, 27, 1349; (a) X. Zhu, S. M. Mahurin, S-H An, C-L Do-Thanh, C. Tian, Y. Li, L. W. Gill, E. W. Hagaman, Z. Bian, J-H Zhou, J. Hu, H. Liu and S. Dai Chem. Commun., 2014, 50, 7933; (b) A. Modak, M. Pramanik, S. Inagaki and A. Bhaumik, J. Mater. Chem. A, 2014, 2, 11642; (c) J. Wang, S. Xu, Y. Wang, R. Cai, C. Lv, W. Qiao, D. Long and L. Linga, RSC Adv., 2014, 4, 16224; (d) R. Gomes and A. Bhaumik, J. Solid. State. Chem., 2015, 222, 7; (e) P. Arab, M. G. Rabbani, A. K. Sekizkardes, T. Islamoglu and H. M. El-Kaderi, Chem. Mater., 2014, 26, 1385. (a) F. J. Uribe-Romo, J. R. Hunt, H. Furukawa, C. Klock, M. O’ Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 4570; (b) M. G. Rabbani, A. K. Sekizkardes, Z. Kahveci, T. E. Reich, R. Ding and H. M. El-Kaderi, Chem. Eur. J., 2013, 19, 3324; (c) Y. J. Choi, J. H. Choi, K. M. Choi and J. K. Kang, J. Mater. Chem., 2011, 21, 1073. (a) R. Luebke, J. F. Eubank, A. J. Cairns, Y. Belmabkhout, L. Wojtas and M. Eddaoudi, Chem. Commun. 2012, 48, 1455; (b) J. S. Qin, D. Y. Du, W. L. Li, J. P. Zhang, S. L. Li, Z. M. Su, X. L. Wang, Q. Xu, K. Z. Shao and Y. Q. Lan, Chem. Sci., 2012, 3, 2114; (c) K. Liu, B. Y. Li, Y. Li, X. Li, F. Yang, G. Zeng, Y. Peng, Z. J. Zhang, G. H. Li, Z. Shi, S. H. Feng and D. T. Song, Chem. Commun., 2014, 50, 5031. (a) S. Wu, S. Gu, A. Zhang, G. Yu, Z. Wang, J. Jianc and C. Pan, J. Mater. Chem. A, 2015, 3, 878; (b) L. Stegbauer, K. Schwinghammer and B. V. Lotsch, Chem. Sci., 2014, 5, 2789; (c) S. Chandra, S. Kandambeth, B. P. Biswal, B. Lukose, S. M. Kunjir, M. Chaudhary, R. Babarao, T. Heine and R. Banerjee, J. Am. Chem. Soc., 2013, 135, 17853; (d) M. K. Bhunia, S. K. Das, P. Pachfule, R. Banerjee and A. Bhaumik, Dalton Trans., 2012, 41, 1304. (a) M. G. Schwab, B. Fassbender, H. W. Spiess, A. Thomas, X. Feng, and K. Mullen, J. Am. Chem. Soc. 2009, 131, 7216; (b) H. A. Patel, F. Karadas, J. Byun, J. Park, E. Deniz, A. Canlier, Y. Jung, M. Atilhan and C. T. Yavuz, Adv. Funct. Mater., 2013, 23, 2270; (c) H. Furukawa and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 8875; (d) S. Hug, M. B. Mesch, H. Oh, N. Popp, M. Hirscher, J. Senkerd and B. V. Lotsch, J. Mater. Chem. A, 2014, 2, 5928. S. T. Yang, J. Y. Kim, J. Kim and W. S. Ahn, Fuel, 2012, 97, 235.
ChemComm Accepted Manuscript
DOI: 10.1039/C5CC02147B
