Search

Two kinds of fluorescent conjugated microporous polymers containing pyrazine moieties were prepared by the polymerization reaction of 2,5-di-triphenylamine-yl-pyrazine (DTPAPz) and N,N,N',N'-tetrapheny-2,5-(diazyl) pyrazine (TDPz) with 2,4,6-trichloro-1,3,5-triazine (TCT) through Friedel-Crafts reaction using the methanesulfonic acid as a catalysts. Both CMPs have high thermal stability and decomposition temperature reaches above 596 and 248 °C under nitrogen atmosphere, respectively. By right of porous morphology and electron-donating nitrogen, as well as electron-rich π-conjugated structures, the adsorption performance for iodine vapor on the CMPs is very excellent, which can reach 441% and 312%. In addition, fluorescence studies showed that the two CMPs exhibited high fluorescence sensitivity to electron-deficient iodine, o-nitrophenol (o-NP), and picric acid (PA) via fluorescence quenching.

Two bitetrazole‐based porous organic polymers (POPs), TBTZ and HBTZ, have been synthesized by nucleophilic substitution reactions with yields up to 79.08% and 78.81%, respectively. After a series of characterization, these two POPs show good chemical stability, thermal stability, and high pore properties. Through performance tests, we found that the two POPs show dual functions due to the introduction of bitetrazole, capturing iodine and fluorescence sensing I2 and 4‐nitrophenol (p‐NP). First, owing to the plenty of nitrogen affinity sites, both TBTZ and HBTZ show excellent iodine adsorption with 3.54 and 5.66 g g−1, respectively. The higher adsorption amount of HBTZ for iodine than TBTZ is due to the larger specific surface area of HBTZ than TBTZ, and stronger interaction of cyclophosphonitrile unit with iodine are than triazine ring with iodine. Second, on account of their excellent conjugated properties and nitrogen‐enriched structures, TBTZ and HBTZ exhibit high sensitivity to I2 and p‐NP with KSV of 3.97 × 103 and 5.49 × 104 L mol−1 and limits of detection of 8.00 × 10−10 and 5.46 × 10−11 mol L−1, respectively. The former is the photo‐induced electron transfer mechanism, while the latter is the energy transfer mechanism. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are novel porous organic materials with structural tunable features and have great potential applications in iodine adsorption and fluorescence sensing. We explore the effect of linker length on the function of the COFs prepared through the Schiff base aldehyde‐amine polycondensation with different linkers in lengths. The linker length affects the specific surface area, aperture, pore volume, and electron density of the COFs, thus affecting the ability to bind with other substances. The synthetic HPDA and HDAT in this report showed excellent iodine adsorption of 4.53 and 3.92 g g−1, respectively. Meanwhile, HPDA and HDAT are quite sensitive to the fluorescence sensing of picric acid (PA) and o‐nitrophenol (o‐NP) with their limits of detection of 1.86 × 10−11, 4.69 × 10−11 mol L−1, respectively. HPDA and HDAT can be outstanding adsorbents for iodine and excellent fluorescent sensors for PA and o‐NP, respectively. [ABSTRACT FROM AUTHOR]

We present the preparation and characterization of a novel class of secondary amine‐based porous organic polymers (POPs: TDPA and TTPBTA), and their iodine adsorption, fluorescence sensing properties for the first time. Two secondary amine‐based POPs were synthetized by Friedel−Crafts polymerization reaction catalyzed via methylsulfonic acid with yields of 22.51 and 54.44%. The thermal stability of resulting POPs run up to above 268 and 568°C, and their BET specific surface areas are 56.5 and 2.49 m2 g−1, respectively. Their iodine adsorption and fluorescent sensing properties are comparable to that of triphenylamine (TPA)‐based (tertiary amine) POPs. The resulting POPs display excellent sorption abilities to iodine molecules with the iodine adsorption capacity of about 3.93 and 1.64 g g−1. Adsorbed iodine is easily desorbed by heating or washing with organic solvents, which make them reusable. They can also adsorb iodine from cyclohexane solution. Moreover, the POPs possess excellent fluorescent sensing property for I2 with Ksv of 1.85 × 104 and 6.56 × 104 L mol−1, as well as the limits of detection (LODs) of 1.62 × 10−11 and 6.86 × 10−12 mol L−1. The performance of adsorbing and fluorescence sensing iodine can be explained by electron transfer mechanism. [ABSTRACT FROM AUTHOR]

The covalent triazine‐based framework (TDPDB) has been prepared by Friedel‐Crafts polymerization reaction of N,N′‐diphenyl‐N,N′‐di(m‐tolyl)benzidine (DPDB) with 2,4,6‐trichloro‐1,3,5‐triazine (TCT) catalyzed by methanesulfonic acid. The yield of the reaction (94.85%) is very high. TDPDB was provided with Brunauer‐Emmett‐Teller specific surface area of 592.18 m2 g−1 and pore volume of 0.5241 cm3 g−1. TDPDB demonstrated an excellent capacity for capturing iodine (3.93 g g−1) and an outstanding ability to fluorescent sensing to iodine with Ksv of 5.83 × 104 L mol−1. It also showed high fluorescent sensing sensitivity to picric acid. [ABSTRACT FROM AUTHOR]

Two tetraphenylethylene-based fluorescent conjugated microporous polymers were obtained by the polymerization of a CH 3 SO 3 H catalyzed Friedel−Crafts polymerization reaction. The resulting CMPs show high thermal stability with a decomposition temperature above 575 and 487 °C, and have the porosity with BET surface area of 564.8 and 44.1 m2 g−1, respectively. Due to the introduction of tetraphenylethylene units, the CMPs have excellent fluorescence sensing performance for I 2 with high Ksv of 1.53 × 105 and 9.07 × 104 L mol−1. Taking advantage of such porosity, effective sorption sites, and charge-transfer interactions, which display excellent I 2 adsorption capacity in vapor with the uptake of up to 3.41 and 2.91 g g−1. Image 1 • Two TPE-based CMPs were prepared by Friedel−Crafts polymerization reaction catalyzed a CH 3 SO 3 H. • The TPE-based CMPs have the porosity with BET surface area of 564.8 and 44.1 m2 g−1. • The TPE-based CMPs exhibit high sensitivity to iodine with Ksv of 1.53 × 105 and 9.07 × 104 L mol−1. • The TPE-based CMPs display high I 2 adsorption capacity with the uptake of up to 3.41 and 2.91 g g−1. [ABSTRACT FROM AUTHOR]

• The CMPs possess high BET surface area, can both adsorb and fluorescent sense iodine. • The both CMPs show excellent efficient absorption performance for iodine vapor up to 4.15 and 3.65 g g−1. • TS-TAD and TS-TADP exhibits high sensitivity to I 2 , o-NP, and PA via fluorescence quenching. Two new spirobifluorene-based conjugated microporous polymers, TS-TAD and TS-TADP, were constructed via Friedel-Crafts coupling reactions. TS-TAD and TS-TADP possess high BET surface area of 828 and 783 m2 g−1, large pore volume of 1.51 and 0.54 cm3 g−1, good stability, and display excellent guest uptake of 4.15 and 3.65 g g−1 in iodine vapour as well as reversible adsorption of iodine in solution. The specific surface areas of CMPs were increased by the introduction of bispirofluorene rings compared with the corresponding parent polymers. TS-TAD has a similar structure to TS-TADP, but possesses larger specific surface area and pore values than TS-TADP, hence, TS-TAD has a higher adsorption capacity for iodine than TS-TADP. Moreover, the adsorption rate of TS-TAD is slower than that of TS-TADP in I 2 vapor, while it is faster than that of TS-TADP in cyclohexane solution. We also highlight that the both resulting CMPs exhibit outstanding performance for fluorescent sensing to iodine and nitroaromatic compounds, thus making the resulting CMPs ideal absorbent materials for reversible iodine capture, sensing iodine and nitroaromatic compounds to address environmental issues. [ABSTRACT FROM AUTHOR]

Abstract Poly{tris[4-(2-thienyl)phenyl]amine} (PTPATTh) and poly[tris(4-carbazoyl-9-yl phenyl)amine] (PTPATCz) are thiophene-based and carbazole-based conjugated microporous polymers with triphenylamine as cores. Here we present detailed evidence of highly efficient and iodine capture in both CMPs. Thanks to the propeller-like structure, high porosity, extended π-conjugation and electron-rich characteristics, the both CMPs display efficient, adsorption of I 2 in vapor (up to 3.13 and 2.56 g g−1) and in solution. Two ways to release the adsorbed iodine were explored: either slow release into ethanol or quick release upon heating (with a high degree of control). In addition, the both CMPs could be recycled while maintaining 70% iodine uptake capacity (up to 85%). Thus making the resulting CMPs ideal absorbent materials for iodine capture to address environmental issues. Graphical abstract fx1 Highlights • We investigated the iodine adsorption performance of PTPATTh and PTPATCz. • The PTPATTh shows lower specific surface area (S BET = 594 m2 g−1) than PTPATCz (S BET = 894 m2 g−1) does. • The PTPATTh (3.13 g g−1) shows higher adsorptivity than PTPATCz (2.56 g g−1). • The phenyl ring, N and S heteroatoms and charge-transfer interactions are the effective sorption sites to iodine. [ABSTRACT FROM AUTHOR]

Two thiophene- and pyrene-based conjugated microporous polymers poly[1,3,6,8-tetra(2-thiophenyl)pyrene] and poly[1,3,6,8-tetra(3-thiophenyl)pyrene] (PTThP-2 and PTThP-3) were designed and prepared through a FeCl3 oxidative coupling polymerization. The PTThP-2 and PTThP-3 possess considerable BET surface area of over 370.8 m2 g−1 and 748.2 m2 g−1, large pore volume of 0.544 cm3 g−1 and 0.573 cm3 g−1, good stability, and display excellent guest uptake of 1.62 and 2.00 g g−1 in iodine vapour. Furthermore, incorporation of pyrene and thiophene moieties into these polymers can induce high fluorescence in the dispersions of tetrahydrofuran (THF), which make them sensing electron-deficient iodine via fluorescence quenching with the Ksv of 1.99 × 103 and 5.09 × 103 L mol−1, and the limit of detection of 7.54 × 10−8 and 2.95 × 10−8 mol L−1, respectively. [ABSTRACT FROM AUTHOR]