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A Schiff Base Substituent Triggered Efficient Deboration Reaction and Its Application in Highly Sensitive Hydrogen Peroxide Vapour Detection Yanyan Fu, Jun Jun Yao, Wei Xu, Tianchi Fan, Zinuo Jiao, Qingguo He, Defeng Zhu, Huimin Cao, and Jiangong Cheng Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.6b01057 • Publication Date (Web): 20 Apr 2016 Downloaded from http://pubs.acs.org on April 21, 2016

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Analytical Chemistry

A Schiff Base Substituent Triggered Efficient Deboration Reaction and Its Application in Highly Sensitive Hydrogen Peroxide Vapour Detection

Yanyan Fu*a , Junjun Yaoa,b , Wei Xu a,b, Tianchi Fan a,b, Zinuo Jiaoa,b, Qingguo He*a, Defeng Zhu a, Huimin Cao a, and Jiangong Cheng*a

a

State Key Lab of Transducer Technology, Shanghai Institute of Microsystem andInformation Technology, Chinese Academy of Sciences, Changning Road 865,Shanghai 200050, China. E-mail: [email protected]; [email protected]; [email protected] b

University of the Chinese Academy of Sciences, Yuquan Road 19, Beijing,100039, China

ABSTRACT: Organic thin film fluorescence probe, with the advantages of no polluting the analyte and fast response, has attracted many attention in explosive detection. Different with nitro explosive, the peroxide-based explosives is hardly to be detected because of its poor ultraviolet absorption and lack of aromatic ring. As the signature compound of peroxidebased explosives, H2O2 vapour detection became more and more important. Boron ester or acid is considered to be a suitable functional group for the detection of hydrogen peroxide due to its reliable reactive activity. Its only drawback lies on its slow degradation velocity. In this work, we try to introduce some functional group to make the boron ester easily to be oxidized by H2O2. Herein, OTB was synthesized and its imine derivatives OTBXA were easily obtained just by putting OTB films in different primary amines vapours. OTBXA shows fast deboronation velocity in H2O2 vapour compared with OTB. The complete reaction time of OTBPA was even shortened 40 times with a response time of second. The detection limit for H2O2 vapour was as low as 4.1 ppt. Further study showed that it is a general approach to enhance the sensing performance of borate to hydrogen peroxide (H2O2) vapour by introducing imine into aromatic borate molecule via a solid/vapour reaction.

1. Introduction During the latest decades, trace explosive detection continue to receive particular attention due to the exigent demand from public security.1 Among the explosives, detection methods for nitro explosive such as TNT, DNT received a wide attention.2-6 However, a reliable detection method for peroxide-based explosives (such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), and hexamethylene triperoxide diamine (HMTD)) and their

precursor chemicals still pose challenges considering their sensitivity to mechanical stress, low stability as well as lack of UV absorbance or fluorescence.7-11 Compared to other mature detection method like electrochemical method and mass spectrometry, fluorimetric sensing is a promising approach to detect peroxide-based explosives because of its high sensitivity, low cost and portable detection devices.12 As the most important starting material and degradation product of peroxide explosive, H2O2 is considered as

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signature compound for peroxide-based explosives.13 There are many smart fluorescent receptors have been reported by researchers14-16 capable for H2O2 detection. Among them, one of the most commonly used functional group is an aromatic boron ester or acid 17 for its excellent photostability, reliable reactivity as well as its easy synthesis. The only drawback is that the deboronation reaction rate is usually slow (costing many minutes or even several hours) making the sensing process timeconsuming.18 To accelerate the deboronation reaction in H2O2, our group once proposed using ordered assembly arrays of ZnO nanorods as catalyzing substrate and the deboronation reaction was 42 times faster compared with that on quartz substrate.19, 20 Nevertheless, the preparation of such nanorodes still needs additional effort. Zang et al reported that H2O2-mediated oxidation of aryl boronates can be speeded by addition of some organic base, such as trtrabutylammonium hydroxide (TBAH).21, 22 However, our group discovered that these stronger amine like TBAH and secondary amine could accelerate the photo-oxidation of special arylboronate offering corresponding phenols without H2O2.23, 24 In this contribution, we search for a versatile and easy way to realize the efficient detection of H2O2. Considering the phase separation of the additive or special nano substrate, a direct molecular modification of aromatic borate will be a more efficient way to get an excellent H2O2 probe. Based on this cognition, we propose that introducing a specific organic amine in molecule with moderate alkaline may accelerate the oxidation conversion rate of boron ester by H2O2 and also keep its stability in O2. Considering that, firstly, the alkalescence of imine is weaker than that of secondary amine. Secondly, the imine is easily formed via a simple Schiff-base reaction, and thirdly, imine is easily decomposed during a column chromatography separation. Thus we designed a precursor molecule OTB, followed by a solid/vapour Schiff base reaction between OTB film and primary amine vapour to afford the probe (OTBXA).

Scheme 1 Deboronation of OTB and OTBXA.

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2. Experimental Section 2.1 Materials and Measurements All solvents and reagents were obtained from commercial sources and used as received. UV-vis absorption and fluorescence analysis were conducted on a Jasco V-670 spectrophotometer and a Jasco FP 6500 spectrometer, respectively. The NMR spectra were obtained on a Brucker DRX500 instrument, and tetramethylsilane (TMS) was used as an internal standard. Mass spectra were recorded on BIFLEX III MALDI-TOF (Brucker Daltonics Inc.) and GCT-MS Micromass UK mass spectrometers. Unless otherwise noted, all the films were prepared from their THF solutions with concentrations as 5mg/mL on (10×20 mm) quartz plates by spin-coating method at 2200 rpm. The films were all placed in vacuum for 1 hour before use. The fluorescence responses of films to various analytes were progressed by inserting the films into sealed vials (3.8 mL) containing cotton and analytes at room temperature, which prevents direct film analyte contact and helps to maintain a constant vapour pressure. The fluorescence time-course responses were recorded immediately after exposing the films to analytes at an angle of 60° to the incident light. All the theoretical calculations were performed by DMol3 program in the Materials Studio 8.0, which is one of the quantum mechanical code using density functional theory. BLYP function of generalized gradient approximation (GGA) level was used to calculate the optical absorption spectra and the energy level of the molecular orbital. The detail methodology and parameters are listed in Table S1 in the supporting information. 2.2 Synthesis

Synthesis of 4-(phenyl(4-(4,4,5,5-tetramethyl-1,3,2dioxaborolan-2-yl)phenyl)amino)benzaldehyde (OTB): To a solution of 742 mg N, N-diphenyl-4-(4,4,5,5tetramethyl-1,3,2-dioxaborolan-2-yl) aniline in 4 mL DMF, 1.5 mL POCl3 were added. The mixture was stirring at 90°C for 1 hour. After the reaction solution was cooled to room temperature, it was poured into the ice-water mixture and stirred for another hour. Then the solution was extracted with dichloromethane. And the extract was dried over anhydrous MgSO4. After filtration, the solvent was removed through rotary evapouration and the residue was purified by silica gel chromatography eluted with petroleum ether and dichloromethane to light yellow solid (410 mg, 51%).1H NMR (500 MHz, CDCl3, ppm) δ 9.81 (s, 1H), 7.77-7.75 (d, 2H, J = 8.5 Hz), 7.69-7.67 (d, 2H, J = 8.5 Hz), 7.34-7.31 (m, 2H), 7.18-7.12 (m, 5H), 7.07-7.05 (d, 2H, J = 8.5 Hz), 1.34 (s, 12H) 13C NMR (125MHz, CDCl3) δ 190.36, 152.97, 148.92, 146.01, 136.19, 131.20，129.73, 129.69, 126.46, 125.26, 124.47, 120.44, 83.78, 29.65, 24.84 HRMS:


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calcd M+ for 400.2083 C25H27BNO3; found 400.2083.

Synthesis of (E)-N-phenyl-4-((propylimino)methyl)N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2yl)phenyl) aniline (OTBPA): The drop-casted film of 4(phenyl (4-(4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) phenyl) amino) benzaldehyde (OTB) was put aside in an atmosphere of n-propylamine vapour. After 5 minutes, the exposed film was taken out and dried in vacuum oven to remove the volatile remainder. Then the species on the film were dissolved in CDCl3 and the 1H-NMR spectrum was recorded. The high resolution mass spectrum (HRMS), 1H-NMR and 13C NMR spectroscopies exhibit that the structure of the final product was consistent with the expected Schiff’s base structure OTBPA. 1HNMR(500MHz, CDCl3, 25 °C, TMS): δ=8.18 (s, 1H)，7.707.68 (d, 2H, J=10 Hz), 7.59-7.57 ((d, 2H, J=10 Hz), 7.127.05(m, 9H), 3.56-3.53 (m, 2H), 1.73-1.69 (m, 2H),1.37 (s, 12H), 0.96-0.93 (m, 3H). 13C NMR (125MHz, CDCl3) δ160.31, 149.97，149.54, 146.91，138.68，135.96，130.52, 129.46, 129.10, 128.39, 125.63, 124.16,124.09, 123.19, 122.99, 122.91, 120.26,116.67, 83.67, 63.45, 43.72, 29.69, 26.23, 24.86, 24.60, 24.13, 24.08, 23.65, 11.83, 11.78, 11.25 HRMS: calcd M+ for C28H34BN2O2 441.2709; found 441.2713.

Synthesis of (E)-4-(phenyl (4-((propylimino) methyl) phenyl) amino) phenol: The drop-casted film of (E)-Nphenyl-4-((propylimino) methyl)-N-(4-(4, 4, 5, 5tetramethyl-1, 3, 2-dioxaborolan-2-yl) phenyl) aniline (OTBPA, R= propyl) was put aside in an atmosphere of H2O2 vapour. After 5 minutes, the exposed film was taken out and dried in vacuum oven to remove the volatile remainder. Then the species on the film were dissolved in CDCl3 and the 1H-NMR spectrum was recorded. The high resolution mass spectrum (HR-MS) and the 1H-NMR spectroscopies exhibit that the structure of the final product was. 1H-NMR(500MHz, CDCl3, 25 °C, TMS): δ=8.14(s, 1H)，7.52-7.50 (d, 2H, J=8.5 Hz), 7.24-7.23 (d, 2H, J=8 Hz), 7.11-7.10 (d, 2H, J= 8 Hz), 7.02-7.01(m, 3H), 6.92-6.90 (d, 2H, J=8.5 Hz), 6.79-6.78 (d, 2H, J=8 Hz), 3.82(s, 1H), 3.56-3.53 (m, 2H), 1.76-1.73 (m, 2H), 0.95-0.88 (m, 3H). 13C NMR (125MHz, CDCl3) δ161.69, 154.70, 151.02, 147.08, 138.52, 135.98, 131.43, 129.60, 129.49, 129.23, 128.70, 128.58, 127.26, 125.83, 125.68, 124.80, 124.25, 123.16, 123.07, 117.90, 116.84, 116.72, 83.70, 82.95, 63.03, 24.84, 24.56, 23.96, 11.73 HRMS: calcd M+ for C22H23N2O 331.1805; found 331.1806.

Synthesis of 4-(phenyl(4-(6-(4,4,5,5-tetramethyl-1,3,2dioxaborolan-2-yl)pyren-1yl)phenyl)amino)benzaldehyde (OTPB): To a mixture of 454mg 1,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2yl)pyrene, 351mg 4-((4bromophenyl)(phenyl)amino)benzaldehyde in THF solution, tetra (triphenylphosphine)-palladium [Pd(PPh3)4] (1.0 Mol %) in degassed THF and a drop of 2 M potassium carbonate aqueous solution were added. The mixture was stirred at 70 °C for 72 h under the protection of argon. Then the solvent was evapourated and the residue was purified by column chromatography on silica gel using hexane and dichloromethane as eluent to afford pale yellow product OTPB (yield 32%). 1H-NMR(500MHz, CDCl3, 25 °C, TMS): δ=9.85 (s, 1H), 9.10-9.07(m, 1H), 8.56-8.54 (d, 1H, J= 7.5Hz), 8.33-8.21 (m, 2H), 8.17-7.99 (m, 4H), 7.767.74 (m, 2H), 7.61-7.59 (m, 2H), 7.43-7.40 (m, 2H), 7.247.22 (m, 4H)，7.18-7.16 (m, 2H), 1.47(s, 12H) 13C NMR (125MHz, CDCl3) δ153.37, 146.24, 145.36, 137.83, 137.25, 137.06, 136.04, 136.25, 134.11, 133.83, 133.26, 132.98, 131.98, 131.94, 131.41, 130.68, 130.32, 129.91, 129.45, 139.41, 128.56, 128.46, 128.26, 128.16, 127.80, 127.69, 127.64, 127.47, 127.36, 126.64, 126.61, 126.24, 125.82, 124.97, 124.70, 124.97,124.70, 124.36, 124.02, 119.85, 119.78, 83.97,83.93, 39.01, 38.71, 34.16, 29.52, 25.11, 22.99, 22.68, 20.19, 19.20, 14.43, 11.42 HRMS: calcd M+ for C41H34BO3N 598.2663; found 598.2673.

Synthesis of 4-((4-(9,9-dioctyl-7-(4,4,5,5-tetramethyl1,3,2-dioxaborolan-2-yl)-9H-fluoren-2yl)phenyl)(phenyl)amino)benzaldehyde(OTFB) : To a 1:1.5 mixture of 9, 9-dioctylfluorene-2, 7-bis (4, 4, 5, 5tetramethyl-1, 3, 2-dioxaborolane) and 4-((4bromophenyl)(phenyl)amino)benzaldehyde, tetra (triphenylphosphine)-palladium [Pd(PPh3)4] (1.0 Mol %) in degassed THF and a drop of 2 M potassium carbonate aqueous solution were added. The mixture was stirred at 70 °C for 72 h under the protection of argon. Then the solvent was evapourated and the residue was purified by column chromatography on silica gel using hexane and dichloromethane as eluent to afford pale yellow product OTFB (yield 56%). 1H-NMR(500MHz, CDCl3, 25 °C, TMS): δ=9.82 (s, 1H), 7.83-7.75 (m, 1H), 7.71-7.62 (m, 5H), 7.577.55 (m, 2H), 7.38-7.31 (m, 3 H), 7.24-7.20 (m, 6H), 7.187.17(d, 1H, J= 7.5 Hz), 7.15-7.14(d, 1H, J= 7.5 Hz), 2.05-1.99 (m, 4H), 1.39 (s, 12H), 1.20-1.17 (m, 4H), 1.15-1.03 (m, 16H), 0.87-0.77 (t, 6H), 0.64(m, 4H) 13C NMR (125MHz, CDCl3) δ 153.37, 153.23, 150.12, 146.12, 146.11, 145.28, 143.67, 140.33, 139.46, 138.19, 133.83, 131.33, 131.29, 129.80, 129.72, 129.32, 129.14,128.86, 128.32, 126.40, 126.31, 126.26, 125.67, 125.24,


Analytical Chemistry 125.11, 121.14, 120.44, 119.64, 119.64, 119.36, 119.04, 83.72, 55.23, 40.25, 31.75, 29.95, 29.16, 24.94, 23.70, 22.57, 14.04 HRMS: calcd M+ for C54H66BNO3 787.5136; found 787.5145.

3. Results and Discussion

1.0 OTB OTBPA

0.5

0.0 300

400

500

Nor. PL Int. (a.u.)

3.1 Optical properties and structure characterization

Nor. Abs. (a.u.)

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tionship between the sensing behaviour of OTBPA films and the concentration of film fabrication is inverstigated. Fig. S12 indicates that the photo bleaching of OTBPA films made from different OTB concentration of 1 mg/mL, 5 mg/mL, 10mg/mL and 15mg/mL, respectively, are about 17%, 1%, 0.5% and 0.4% upon continuous excitation within 300 s. It means that the film made of concentrated solution has better optical stability. Contrary to the photo stability, upon exposure to H2O2 vapour, corresponding fluorescence quenching of OTBPA films are 92%, 89%, 51% and 21%, respectively. This means thinner film is more favorable for vapour sensing. To balance the photo stability and sensitivity, appropriate concentration should be chosen. Herein, 5 mg/mL is selected as an optimized concentration for preparing OTBPA films.

600

Wavelength(nm) Figure 1. Normalized absorption and fluorescence spectra of OTB and OTBPA in solid state. As shown in Fig.1, the maximum absorption and emission peak of OTB solid films were located at 366 and 466 nm, respectively. Compared with OTB, the UV-vis spectra of OTBPA kept almost unchanged with the max absorption peak at 365 nm. Nevertheless, the fluorescent spectra shifted from 466 to 445 nm. Such fluorescence changes were along with the obvious fluorescence color from light blue to blue violet.

3.2 Sensory properties To study the efficiency of deboronation reaction between OTB/OTBPA and H2O2 vapour, the sensory response of OTB film on quartz plate to H2O2 was firstly investigated. According to our previous study, the sensing behaviour of fluorescent film is partly determined by the thickness of the film. The thickness could be well controlled by the concentration of the probe solution. Typically, a too low concentration results in a very thin film, nice sensing efficiency but large photo bleaching effect. While a too high concentration leads to a thick film, poor sensing performance but less photo bleach25 ing . Unless other pointed, the probe concentration here used for film fabrication is 5 mg/mL which is an optimized concentration. As shown in Fig 2a, the OTB film showed good photo stability upon consequent exposure to air. While in H2O2 vapour, its fluorescence was quenched slowly with a fluorescence quenching ration of 36% within 300 s. Such fluorescence quenching could not easily be distinguished by naked eye. Further study indicates it takes more than 100 min for OTB to completely quench its fluorescence in H2O2 vapour (Fig. S11). As for OTBPA, it also exhibited quite well photo stability in air (Fig 2b). Upon exposure to H2O2 vapour, 89% fluorescence was quenched within 150 s exposure, after that no any emission change could be detected exhibiting a complete reaction time at about 150 s. The huge fluorescence intensity change could be readily distinguished by naked eyes fluorescence colour as shown in Fig 2b. The result suggests that the reaction time was shortened at least 40 times when OTB was replaced by OTBPA. The detailed rela-

Figure 2. (a) Fluorescence stability of OTB film (black) in air and its sensitivity to hydrogen peroxide vapour (blue) at room temperature after 300 s exposure to H2O2 (ex 366nm, em 466nm). The inset picture was its fluorescence responses before and after exposure in H2O2 for 300 s. b) Fluorescence stability of OTBPA (black) and its sensitivity to hydrogen peroxide vapour (blue) at room temperature after 300s exposure to H2O2 (ex 365nm, em 445nm). The inset picture was their fluorescence responses before and after exposure for 300 s. To further investigate the effect of different kind of imine on the velocity of deboronation reaction, the OTB films were put into several typical primary amines including npropylamine, n-hexylamine, n-octylamine and benzylamine to prepare films containing different imines. The newly formed films were named as OTBPA, OTBHA, OTBOA and OTBA, respectively. Compared with OTB, the fluorescence spectra of these newly formed films all showed blue shift


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with Δλmax of -21 nm, -23 nm, -23nm and -40 nm for OTBPA, OTBHA, OTBOA and OTBBA, respectively (Fig S13). Table 1 also summarized the complete degradation time (CDT) of these new formed films upon exposure to H2O2 vapour. All of the probe films with imine structure showed faster deboronation velocity compared with OTB. The CDT in saturated H2O2 vapour are 100, 2.5, 11, 20 and 35 min for OTB, OTBPA, OTBHA, OTBOA and OTBBA, respectively (Fig S11, Fig S14-Fig S16). It seems that the longer alkyl chain (such as hexyl and octyl) and the bigger steric hindrance (such as benzyl) in imine are both adverse for the quick sensing. OTBPA has the simplest structure but showed the best sensing performance compared with other three probes.

OTB

OTBPA

OTBHA

OTBOA

OTBBA

PL,λmax (nm)

466

445

443

443

426

CDT (min)

100 ±5%

2.5±5%

11±5%

20±5%

35±5%

Table 1. The photoluminence emission maximum (PL λ max) of OTB, OTBPA, OTBHA, OTBOA and OTBBA and the complete deboronation time (CDT) of OTB, OTBPA, OTBHA, OTBOA and OTBBA in saturated H2O2 vapour.

anol, toluene, ethyl acetate and water were selected as interference reagents and the interaction of the probe with these solvents were investigated. No obvious fluorescence intensity change (less than 2 %) of the films was observed upon exposure to these vapours indicating the sensing film possessed excellent selectivity towards H2O2 vapour.

3.3 Sensing mechanism and the expansion of sensing method

To deeply investigate why imine can accelerate the deboronation reaction, we calculated the orbitals of OTB and OTBPA using DMol3 of Materials Studio software. Figure 4 presented the optimized molecular structures and charge distribution of the HOMO and LUMO of OTB and OTBPA. As shown in Fig 4, the HOMO and LUMO level of OTB were -4.80 eV and -2.38 eV, respectively. As for OTBPA, the HOMO level and LUMO level was elevated to -4.47 eV and -2.01 eV relative to OTB. It indicates that the introduction of the imine can enhance the HOMO level and reduce the energy gap of material. In other words, the OTBPA is easier to be oxidized compared with OTB.

To estimate the detection limit, the changes in fluorescence intensity of OTBPA films exposed to H2O2 vapours at eight different concentrations were measured. And the intensity quenching data (1- I/I0) are well-fitted to the Langmuir equation with an assumption that the quenching efficiency or increasing efficiency is proportional to the surface adsorption of amine vapour. The detection limits could be obtained as low as ~4.1 ppt according to its fitted plot.

1

0.1

1-I/I0

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0.01

4.1ppt -7

10

-5

10

-3

10

-1

10

1

10

Concentration(ppm)

Figure 3 Fluorescence quenching efficiency (1-I/I0) as a function of the vapour pressure of H2O2 at 445 nm: data (error ± 5%) fitted with the Langmuir equation.

Except for sensitivity and stability, selectivity, also called anti-interference capability, is another important factor of a probe. Several common organic solvents including dichloromethane, tetrahydrofuran, acetone, eth-


Analytical Chemistry Figure 4. Optimized molecular structures and molecular orbitals of OTB (top) and OTBPA (down). -4

1.0x10

OTB

-5

Current (A)

8.0x10

-5

6.0x10

-5

4.0x10

Scheme 2 Structures of OTPB and OTFB.

-5

2.0x10

4. Conclusion

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Potencial (V vs SCE) -4

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-5

6.0x10

-5

4.0x10

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-0.5

0.0

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2.0

In this work, an efficient method to enhance deboronation efficiency of borate for hydrogen peroxide vapour sensing has been developed. By exposure to primary amine, the molecule which contains both arylboronate group and aldehyde group such as OTB, OTPB, and OTFB can all form new films with imine structures. These new films sensing property to H2O2 are tremendously improved, suggesting the introducing a moderate alkaline in arylboronate molecule could accelerate the oxidation conversion rate of boron ester. The response time is several seconds and the detection limit can be as low as ∼4.1 ppt. Such work provides a smart strategy for the design of highly efficient fluorescent probe for peroxide explosives vapours. This Schiff base substitute aromatic boronate molecules are an ideal candidate for chemical detection and analysis of H2O2 vapour in environmental monitoring and public safety.

Potencial (V vs SCE) Figure 5. Cyclic voltammetric curves of OTB and OTBPA.

To verify the calculation result, we also tested the cyclic voltammetry property of OTB and OTBPA (Fig 5). The oxidation potential of OTB and OTBPA are 0.86 V and 0.29 V, respectively. Obviously, the imine unit can significantly improve the reductive ability of borate compound. Therefore the rate of deboronation reaction will be significantly improved. Both electrochemical data and calculation result support that the introduction of a group with moderately alkaline in borate molecule is beneficial to accelerate the oxidation of the borate. As discussed above, after the aldehyde group was replaced by imine structure, a quick and efficient deboration reaction appeared. To deeply explore the effectivity of this method, we also synthesized another two precursor probes named OTPB and OTFB which have an expanded conjugation length by the introduction of pyrenyl or fluorenyl units. When OTPB and OTFB films were put into n-propylamine vapour for 5 min, respectively, the probe films with imine unit were formed. Both probe films demonstrated better reaction activities to H2O2 than that of the precursor probe. The CDTs were also shortened 17 times and 20 times accordingly. And as expected, both the orbital calculation and the cyclic voltammetry revealed that the introduction of the imine will decrease the oxidation potential and elevated HOMO level of OTPB and OTFB making the sensing efficiency greatly enhanced (Fig S17-Fig S24).

ASSOCIATED CONTENT SUPPORTING INFORMATION Additional figures as noted in text. The Supporting Information is available free of charge on the ACS Publications website.

AUTHOR INFORMATION Corresponding Author Qingguo He* E-mail: [email protected]; Jiangong Cheng*Email: [email protected]. Yanyan Fu*Email: [email protected].

Notes The authors declare no competing financial interest

ACKNOWLEDGMENT This work is supported by National Nature Sciences Foundation of China (No. 61325001, 21273267, 61321492, 51473182), grant from Youth Innovation Promotion Association CAS (2015190).

REFERENCES


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Table of Contents/Abstract Graphics

A general approach to enhance the sensing performance of borate to hydrogen peroxide (H2O2) vapour is presented. By introducing imine into aromatic borate molecule via a solid/vapour reaction, the velocity of deboronation reaction in H2O2 vapour was increased significantly, which resulted in a response of seconds and a sensitivity of ppt level.

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