Highly selective detection of Au3+ using rhodamine-based modified polyacrylic acid (PAA)-coated ITO

Accepted Manuscript Highly selective detection of Au (PAA)-coated ITO

3+

using rhodamine-based modified polyacrylic acid

Chatthai Kaewtong, Sastiya Kampaengsri, Burapol Singhana, Buncha Pulpoka PII:

S0143-7208(16)31463-2

DOI:

10.1016/j.dyepig.2017.02.033

Reference:

DYPI 5811

To appear in:

Dyes and Pigments

Received Date: 22 December 2016 Revised Date:

14 February 2017

Accepted Date: 17 February 2017

Please cite this article as: Kaewtong C, Kampaengsri S, Singhana B, Pulpoka B, Highly selective 3+ detection of Au using rhodamine-based modified polyacrylic acid (PAA)-coated ITO, Dyes and Pigments (2017), doi: 10.1016/j.dyepig.2017.02.033. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT Highly Selective Detection of Au3+ Using Rhodamine-based Modified Polyacrylic acid (PAA)-Coated ITO Chatthai Kaewtong,*1 Sastiya Kampaengsri,1 Burapol Singhana2 and Buncha Pulpoka3

N

n

∗

ITO

H N O

O

O

O 3+

Au

EDTA

H N N H

O

N H

∗

N

O O

ITO

O O O Si

n N

N

∗

O Si

O

HN

H N

O

O

O

O

N H

nN

O

Au3+

HN

O

N H

N

n

N

O

∗

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O

N

N

O O Si

n O

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O Si

N H

O

n

H N

O

H N

N

O

N

O

AC C

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Rhodamine derivatives grafted on polyacrylic acid (PAA) were designed, synthesized and evaluated as a Au3+selective chemosensor using the rhodamine ring-opening approach. The fluorogenic and chromogenic polymer chemosensors (PAA-Rho1-PAA-Rho4) were constructed via a coupling reaction between PAA and alkylene polyamine groups possessing a different number of donor atoms and chain lengths to yield PAA-Rho1 (84.2%), PAA-Rho2 (80.3%), PAA-Rho3 (91.9%), and PAA-Rho4 (85.1%). Chemical structures and purity of polymeric sensors were characterized by TGA, NMR, TEM and IR. The complexation studies indicate that PAA-Rho3 exhibited the highest selectivity and sensitivity responsive colorimetric and fluorescence Au3+-specific sensor when compared to other metal ions and polymeric sensors. The polymeric sensors are non-fluorescence in the spirolactam form and could be selectively converted into the fluorescence ring-opened amide form in the presence of Au3+, leading to the fluorescence enhancements and colorimetric changes. In addition, the fluorescent conjugated polymer film as the chemosensors were fabricated by chemical modification on ITO substrate, which created new fluorescent film sensors (PAA-Rho3-ITO). Further study showed that the sensing process is reversible by rinsing with EDTA solutions; the lower detection limit was less than that obtained from uncoated polymer film PAA-Rho3, and the response time was less than 40 seconds. The super sensitive response, good reversibility, and very fast response time, make the fluorescent film sensors a promising Au3+ sensor for environmental and biological applications.

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ACCEPTED MANUSCRIPT

Highly Selective Detection of Au3+ Using Rhodamine-based Modified Polyacrylic acid (PAA)-Coated ITO Chatthai Kaewtong,*1 Sastiya Kampaengsri,1 Burapol Singhana2 and Buncha Pulpoka3 1

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Nanotechnology Research Unit and Supramolecular Chemistry Research Unit, Department of Chemistry and

Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand. Fax: 66 0437 54246; Tel: 66 0437 54246; E-mail: [email protected]

Innovative Nanomedicine Research Unit, Chulabhorn International College of Medicine-Thammasat University,

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2

Rangsit Campus, Paholyothin Highway, Klong Luang, Pathum Thani 12120, Thailand. Fax: +66 (0) 2564 4440-9 ext.

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7594; Tel: 02-564-4440-9 ext. 1535 3

Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University,

Bangkok 10330, Thailand. Fax: 66 0221 87598; Tel: 66 0221 87643.

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KEYWORDS: polymeric sensor, film sensor, fluorescence sensor, rhodamine, gold

ABSTRACT: Rhodamine derivatives grafted on polyacrylic acid (PAA) were designed, synthesized and evaluated as 3+

a Au -selective chemosensor using the rhodamine ring-opening approach. The fluorogenic and chromogenic polymer chemosensors (PAA-Rho1-PAA-Rho4) were constructed via a coupling reaction between PAA and alkylene polyamine groups possessing a different number of donor atoms and chain lengths to yield PAA-Rho1

EP

(84.2%), PAA-Rho2 (80.3%), PAA-Rho3 (91.9%), and PAA-Rho4 (85.1%). Chemical structures and purity of polymeric sensors were characterized by TGA, NMR, SEM and IR. The complexation studies indicate that PAA3+

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Rho3 exhibited the highest selectivity and sensitivity responsive colorimetric and fluorescence Au -specific sensor when compared to other metal ions and polymeric sensors. The polymeric sensors are non-fluorescence in the spirolactam form and could be selectively converted into the fluorescence ring-opened amide form in the presence 3+

of Au , leading to the fluorescence enhancements and colorimetric changes. In addition, the fluorescent conjugated polymer film as the chemosensors were fabricated by chemical modification on ITO substrate, which created new fluorescent film sensors (PAA-Rho3-ITO). Further study showed that the sensing process is reversible by rinsing with EDTA solutions; the lower detection limit was less than that obtained from uncoated polymer film PAA-Rho3, and the response time was less than 40 seconds. The super sensitive response, good reversibility, and 3+

very fast response time, make the fluorescent film sensors a promising Au sensor for environmental and biological applications.

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34 35 36 37

1

2

3

medicine , catalysis , and electronics . During these application processes, gold species are inevitably leached into solutions, and as a result, a considerable quantity of gold-containing wastewater is produced and resulted in negative impacts on the environment. The previous report indicated that a huge number of electronic wastes are produced every year, of which the gold content is sometimes 3+

contaminted in wastewater can interact with

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6

unexpectedly higher than that in ores. The Au

phospholipid bilayers to perturb the molecular structure of cells, and thus affect the permeability and 4

functions of ion channels, receptors, and enzymes immersed in the membrane lipid moiety. On the other hand, the demands for gold in recent years are significantly increased while the global resources of gold ores and the corresponding mining capacities are quite limited, which bring serious problems

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5

with regard to the supply of gold. The gold-containing in the wastes can be effectively leached in acid solutions, which provides a resource of gold recovery. Therefore, it is essentially important to find an

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effective method for the recovery of gold from aqueous solution in view point of environment protection and full utilization of gold resource. Conventional methods for the recovery of heavy metals 7

8

9

from aqueous solutions include precipitation , ions exchange , and solvent extraction. Nevertheless, these methods are not effective (incomplete metal removal) or economical (high cost, high reagent and/or energy requirement) because gold-containing wastewater is often characterized by low concentration (<100 mg/L). Compared with conventional methods, adsorption offers distinct advantages for metal ions recovery, including high efficiency, low operating costs, minimal volume of 10

sludge, and more. In the past few years, a molecular sensor has become a powerful tool for sensing and

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24 25 26 27 28 29 30 31 32 33

Gold, one of the precious metals, has been widely used in many fields of modern society, such as

imaging trace amounts of sample because of its simplicity and sensitivity. The molecular sensors contain two basic functional units: a receptor unit and a signaling unit. Rhodamine dyes are widely used as fluorescence probes owing to their high absorption coefficient and broad fluorescence in the visible region of the electromagnetic spectrum, high fluorescence quantum

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2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

I. INTRODUCTION

yields, and photostability after complexes with metal ions by activating a carbonyl group in a 11

spirolactone or a spirolactam moiety. The mechanism is based on the switch off/on of the spirocyclic

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1

moiety mediated by guests. In general, spirolactam formation of rhodamine derivatives is nonfluorescent, whereas its ring-opened amide system by guests gives rise to a pink color and strong fluorescence emission. Recently, rhodamine-based sensors for cations and other analytes have received 2+

2+

2+

3+

3+

−

ever-increasing interest in areas, such as for sensors for Pb , Cu , Hg , Fe , Cr , OCl , NO and other analytes.

12-19

In our previous works, we have successfully designed fluorescence chemosensors for

anions, cations and ditopic receptors utilizing rhodamine B as the fluorophore.

20

A variety of fluorescence cation sensors have been developed by using small molecules as cation receptors. Nevertheless, these materials have shown several problems, such as low mechanical properties and thermal stability, weak chemical union with the metals, poor removal efficiency, high cost and more. In contrast with molecular sensors, film sensors based on polymers exhibit prominent

3

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functional polymers, low cost, and so on. Recently, polyacrylic acid (PAA) has found a wide range of applications by surface modification with functional polymers and specific molecules. PAA grafted with p-t-butylcalix[4]arenediamine and p-t-butyl calix[4]arenediol were prepared and evaluated the adsorption property. These supra-polymeric sensors showed good sorbents for heavy and alkali metal 22

3+

cations. In addition, we also have investigated a selective detection of Au by using polymeric sensors

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which were simply prepared via an amidation reaction between PAA and various mole ratios of N(rhodamine B) lactam-ethylenediamine. It was found that polymeric sensors exhibited the highest 3+

selectivity and sensitivity responsive colorimetric and fluorescence Au -specific sensor over other metal 23

ions. Importantly, PAA has a higher density of carboxylic groups at the backbone and can be used to prepare the functional organic thin films for cation sensing on ITO surfaces and may have interactions

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with metal ions. It is well-known that the more you increase the binding site, the higher binding ability will become.

For these reasons mentioned above, the PAA-based sensors were made by grafting rhodamine

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14 15 16 17 18 19 20 21 22

advantages, such as the ease to fabricate devices, a wide choice of incorporating specific units into

derivatives containing alkylene polyamine groups with different donor atoms and chain lengths as a linker onto the PAA skelaton to obtain hydrophobically modified PAA bearing rhodamine moieties. These rhodamine-modified PAA materials were then immobilized on the ITO substrate to make novel 3+

fluorescent film sensors (PAA-Rho), which could be used as a Au

chemosensor (Scheme 1). The

detection mechanism is based on the switch OFF/ON of the spirocyclic moiety. The rhodamine 3+

derivative is a fluorescence inactive form (OFF), whereas its ring-opened amide form activated by Au

ion becomes a pink color and strong fluorescence emission (ON). The sensors are expected to have high

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1 2 3 4 5 6 7 8 9 10 11 12 13

sensitivity and selectivity for possible applications as thin film sensors.

23

3+

Scheme 1. Proposed selective detection mechanism of Au by using rhodamine-based modified

25

poly acrylic acid (PAA-Rho)-coated ITO

N

n

∗

H N

O

O Si ITO

O

O

26 27 28

n O

O

∗

∗

N

N

EDTA N H

O O

HN

nN

O

H N

O

N H

N

Au3+

O

O O Si

N H

O

H N

H N

N

O

N

O n

AC C

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24

ITO

O

O Si

H N

O

O

O

O

O

O Si

n N

N

O

N H ∗

O Au3+

HN

O N H

N n N

O

N

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1

II. MATERIALS AND METHOD

2 3 4 5 6 7

Chemical and Methods. All reagents were standard analytical grade. PAA (average Mw, ~2000 , PDI

8 9 10 11 12 13 14

Instrumentation. NMR spectra were recorded on a Varian 400 MHz spectrometer in deuterated

15 16 17 18 19

The fracture surface of the polymeric sensors, hybrid material before and after added Au

20 21 22 23 24

Thermogravimetric analysis (TGA) was carried out using TA instruments, SDT Q600 (Luken's drive,

25 26 27 28 29 30 31 32

Determination of acid number. Acid number for PAA was determined according to ASTM D 1045.

33 34 35 36 37

≤1.1)

and

rhodamine

were

purchased

from

Aldrich.

Dicyclohexylcarbodiimide

(DCC),

4-

dimethylaminopyridine (DMAP), and alkylene polyamine were obtained from Merck and used without further purification. Commercial grade solvents, such as acetone, hexanes, dichloromethane, methanol, and ethyl acetate, were distilled before use. DMF was dried over CaH2 and freshly distilled under

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nitrogen gas (N2) prior to use.

chloroform and DMSO-d6. MALDI-TOF mass spectra were acquired on a BiflexBruker Mass spectrometer using 2-cyano-4-hydroxycinnamic acid (CCA) or 2,5-dihydroxy-benzoic acid (DHB) as the

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matrix. UV-vis absorption measurements were performed on a Perkin Elmer Lambda 25 UV/VIS spectrometer. Fluorescence spectra were conducted using a Perkin Elmer luminescence spectrometer LS50B. Infrared spectra were obtained on a Nicolet Impact 410 using KBr pellet. Column

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chromatography was carried out using silica gel (Kieselgel 60, 0.063-0.200 mm, Merck). 3+

were

monitored under the scanning electron microscope (SEM) (LEO 01455VP, Cambridge, England) operated with the voltage of 20 kV. prior to examination.The composite samples were immersed in liquid nitrogen for 30 min and then fractured. The specimens were sputter-coated with gold for

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enhanced surface conductivity.

New Castle, DE). The neat samples (8-10 mg) were loaded in alumina crucible and then non-1

isothermally heated from ambient temperature to 1000°C at heating rates of 20°C min . The TGA was performed in N2 atmosphere. The TGA data were simultaneously recorded online in TA instrument's Q

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series explorer software.

Briefly, PAA (0.1 g) was weighed into a 100 ml Erlenmeyer flask and dissolved in 25 ml of absolute

AC C

ethanol. Then, a few drops of bromothymol blue indicator were added and the solution was titrated with a solution of 0.01 N NaOH. Also, the blank titration was carried out on 25 mL of the solvent used to dissolve the sample. The acid number expressed as the milligrams of NaOH per gram of the sample is as follows: Acid number = [(VNaOH(s)-VNaOH(b))N×56.1]/C, which VNaOH(s) is the volume of NaOH used to titrate a sample, VNaOH(b) is the volume of NaOH used to titrate a blank, N is the normality of the NaOH, and C is gram of the sample. The acid number for PAA was 21.6 . Synthesis. Synthesis of N-(rhodamine B)lactam-derivatives (Rho1–4). They were synthesized by mofidying the synthesis procedures of similar compounds reported in the literatures.

20

Rhodamine B

(0.20 g, 0.42 mmol) was dissolved in 30 mL of ethanol and 0.22 mL (excess) ofalkylenepolyamines (ethylenediamine, diethylenetriamine,triethylenetetraamine, and tetraethylenepentaamine) were added dropwise to the solution and then refluxed overnight (24 hours) until the solution lost its red color. The

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1 2 3 4 5

solvent was removed by evaporation. Water (20 mL) was added to the residue and the solution was

6 7 8 9 10 11

Synthesis of polymeric sensors (PAA-Rho1 – PAA-Rho4). Typically, a mixture of N-(rhodamine

extracted with CH2Cl2 (20 mL × 2). The combined organic phase was washed with water twice and dried over anhydrous Na2SO4. The solvent was removed by evaporation, and the product purified by column chromatography (SiO2; CH2Cl2, MeOH) toafford a pale-yellow solid ofN-(rhodamine B)lactamderivatives(Rho1–4).

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B)lactam-derivative (Rho) and PAA in 20 mL of dried DMF was allowed to react in the presence of DCC and DMAP. The resulting mixture was heated to 50 °C for 1 hour and then heated at reflux overnight. The mixture was cooled down to the room temperature, and the product was precipitated by adding an excess of water. The above dissolution-precipitation cycle was repeated for three times. After drying in

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vacuo over overnight at 45°C, PAA-Rho1 –PAA-Rho4 were obtained as pale-yellow solids.

12 13

PAA-Rho1 (0.121 g): Rho1 0.389 g, 0.802 mmol; PAA 0.040 g; DCC 0.165 g, 0.801 mmol; DMAP 0.049 g,

14 15 16

(bs,ArH), 6.41-6.20 (bs, ArH), 5.57 (d, J=8Hz, ArH), 3.23-2.15 (m, NHCH2CH2), 1.72-1.44 (m, CHCH2), 1.27-

17

PAA-Rho2 (0.123 g): Rho2 0.422 g, 0.800 mmol; PAA 0.040 g; DCC 0.165 g, 0.800 mmol; DMAP 0.049

18 19 20 21 22

g, 0.400 mmol. H NMR (400 MHz, DMSO-d6):7.93 (bs, NHCO), 7.74-7.60 (m, ArH), 7.46 (bs, ArH),

23 24 25 26 27 28

PAA-Rho3 (0.086 g): Rho3 0.212 g, 0.370 mmol; PAA 0.023 g; DCC 0.078 g, 0.37 mmol; DMAP 0.023 g,

29 30 31 32 33

PAA-Rho4 (0.110 g): Rho4 0.363 g, 0.592 mmol; PAA 0.030 g; DCC 0.122 g, 0.592 mmol; DMAP 0.036 g,

34

1

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0.400 mmol.. H NMR (400 MHz, DMSO-d6): 7.93 (bs, NHCO), 7.81 (m, ArH), 7.48 (bs, ArH), 7.02-6.94

-1

1.16 (m, NCH2CH3), and 1.11-0.87 (m, NCH2CH3); IR spectrum (KBr, (cm )): 3632-3415 (OH), 3320 (NH), -1

2968 (=C−H), 2934, 2850 (−C−H), 1684 (C=O), 1625, 1571 (C=C), 1217 (C−O); Mw (NMR) = 5154 g.mol .

1

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7.06-6.79 (bs, ArH), 6.40-6.02 (bs, ArH) 5.55 (d, J = 8Hz, ArH),3.20-2.95 (m, NHCH2CH2), 1.79-1.41 (m, -1

CHCH2), 1.29-1.14 (m, NCH2CH3),and 1.11-0.61 (m, NCH2CH3); IR spectrum (KBr, (cm )): 3593-3435 (OH), -1

3792 g.mol .

1

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3327 (NH), 2953 (=C−H), 2934, 2850 (−C−H), 1630 (C=O), 1576, 1443 (C=C), 1250 (C−O); Mw (NMR) =

0.190 mmol. H NMR (400 MHz, DMSO-d6): 7.92 (bs, NHCO), 7.75 (bs, ArH), 7.49 (bs, ArH), 7.05-6.89 (bs, ArH), 6.38-6.11 (bs, ArH) 5.58 (d, J = 8Hz, ArH), 3.32-1.96 (m, NHCH2CH2), 1.76-1.38 (m, CHCH2), -1

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1.27-1.11 (m, NCH2CH3), and 1.10-0.85 (m, NCH2CH3); IR spectrum (KBr, (cm )): 3641-3401 (OH), 3327 (NH), 2978 (=C−H), 2929, 2855 (−C−H), 1679 (C=O), 1624, 1522 (C=C), 1221 (C−O); Mw (NMR) = 4923 -1

g.mol .

1

0.296 mmol. H NMR (400 MHz, DMSO-d6): 8.19 (bs, NHCO), 7.74 (bs, ArH), 7.49 (bs, ArH), 7.01 (bs, , ArH), 6.43-6.21 (bs, ArH) 5.55 (d, J = 8Hz, ArH), 3.20-2.04 (m, NHCH2CH2), 1.76-1.39 (m, CHCH2), 1.30-1

1.12 (m, NCH2CH3) and 1.12-0.57 (m, NCH2CH3); IR spectrum (KBr, (cm )): 3637-3415 (OH), 3332 (NH), -1

2978 (=C−H), 2929, 2850 (−C−H), 1630 (C=O), 1570, 1516 (C=C), 1246 (C−O); Mw (NMR) = 4720 g.mol .

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Complexation studies. Complexation studies of ligands were carried out by using UV-vis and fluorescence titrations. The complexation abilities of ligands PAA-Rho1–PAA-Rho4 with cations were investigated by spectrophotometric titration in 0.01 mol/L of TBAPF6 in DMSO at 25 °C. 2 mL of the 0.1 g/L PAA-Rho1–PAA-Rho4 solutions were placed in a spectrophotometric cell (1 cm path length). The solutions of cations were added successively into the cell from a microburette. The mixture was stirred for 40 seconds after each addition and its spectral variation was acquired.

8 9 10 11

3+

Competition experiments. Au

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7

was added to the solution containing PAA-Rho3 and other metal

ions. All test solutions were stirred for 1 min and then allowed to stand at room temperature for 30 min. For fluorescent measurements, the excitation was performed at 520 nm, and emission spectra were recorded from 530 to 700 nm.

12

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1 2 3 4 5 6

Polymeric sensor immobilization on the ITO

14 15 16 17 18 19 20 21 22 23

The ITO substrate was cut into a square shapeand cleaned by sequentially sonicating in deionized (dI) water, isopropanol, hexanes and toluene, for 15 min each. The substrates were then dried under a stream of N2 and were plasma cleaned for 3 min. The plasma-treated ITO were immediately soaked in the solution of 10% APTES anhydrous toluene solution at 105 °C under N2 atmosphare for 24 h. After the deposition, APTES-ITO slides were sonicated in toluene for 10 min two times to remove loosely physisorbed APTES, and then dried by the use of a stream of N2 before use. Finally, rhodamine amide

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immobilization was performed by reacting 0.05 g PAA-Rho3 in THF with the APTES-modified ITO substrate using 0.041 g (0.197 mmol) DCC and 0.012 g (0.393 mmol) DMAP as coupling reagents for 12 h at 60 °C. Subsequently, unbound PAA-Rho3 was gently washed away with THF and DMF, and then dried under a gentle stream of N2.

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Sensing studies of PAA-Rho2-ITO by using potentiometry

26 27 28 29

PAA-Rho2-ITO was studied as a sensor having 0.01 M TBACl as electrolyte. Using Teflon cell, TBACl of

30 31 32 33 34 35

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25

0.01 M was injected, until potential signal was kept constant. To study sensing of the hybrid material, different concentrations of cations were held constant for 1,000 s. The change in potential (∆E), [(∆E)=observed potential (E0) − initial potential (Ei)] was acquired simultaneously as a function of time.

III. RESULTS AND DISCUSSION

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1

Scheme 2. Synthetic part ways of PAA-Rho1-PAA-Rho4 NH2 O N HO

N n H

HO

O

O 40

O

NH 60

O

n N H

N

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N

O

1, n = 0 2, n = 1 3, n = 2 4, n = 3

N

N

O

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N

PAA-Rho1, n = 0 PAA-Rho2, n = 1 PAA-Rho3, n = 2 PAA-Rho4, n = 3

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2 3

3+

4 5 6 7 8 9 10 11 12 13 14 15 16

New PAA-based sensors for selective detection of Au ions were designed and prepared by sucessfully

17 18 19 20 21 22 23 24

All characterization data of the synthesized polymeric sensors were demonstrated in Figure 1

grafting the rhodamine B into the PAA skelaton having alkylene polyamines as a linker. Rhodamine polyamines were used in this sensor fabrication since the carbonyl O and amine N atoms could capture the metal ions via the formation of ion-ion and cation-dipole interactions.

20

Also, the condensation

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rection was used in order to attach rhodamine B to ethylenediamine, diethylenetriamine, triethylenetetraamine, and tetraethylenepentaamine under N2 with refluxing for 3 days to afford N(rhodamine

B)lactam-derivatives;

diethylenetriamine

(Rho2),

rhodamine

rhodamine

B

B

ethylenediamine

triethylenetriamine

(Rho1),

(Rho3),

and

rhodamine

B

rhodamine

B

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tetraethylenetriamine (Rho4), respectively. The coupling reaction was subsequently conducted to graft rhodamine derivatives (Rho1-Rho4) onto the PAA backbone via the formation of amide bonds in the presence of DCC/DMAP as coupling reagents under N2 at reflux for 3 days to yield; PAA-Rho1 (84.2%),

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PAA-Rho2 (80.3%), PAA-Rho3 (91.9%), and PAA-Rho4 (85.1%) (Scheme 2). All materials were thoroughly characterized and proven by TGA, NMR, SEM, and FTIR.

and S1-S4. The FTIR spectra of polymeric sensors showed aromatic rhodamine peaks at ∼1676 and 1443 cm , NH amide groups at ∼3300 cm , and carboxylic PAA peak at ∼3600-3400 cm . The TGA curves -1

-1

-1

indicated the decomposition of PAA and rhodamine moieties at ∼175-298 °C and 308-470 °C, respectively. In addition, the SEM images (Figure 1c, 1d) illustrated increasing of the crystallinity and crystalline sizes attributing to π-π interactions and hydrogen bonding of the rhodamine moieties on the PAA skelaton which was concerned with XRD parttern, exhibited the sharp peaks after modifired1

rhodamine (Figure S5). H NMR spectra (Figure S1-S4) also confirmed the formation of polymeric sensor

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1 2

by showing the characteristic signals of -CH2 and -CH groups in the region of ∼1.0–2.9 ppm, amide groups at ∼7.90 ppm and aromatic protons at ∼7.71-5.57 ppm, respectively.

3 4

b)

a)

100

400

5

PAA PAA-Rho1 PAA-Rho2 PAA-Rho3 PAA-Rho4

80 PAA-Rho4

8 9

200

PAA-Rho3

PAA-Rho2

100

60

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7

300

% Weight (mg)

Transmittance

6

40 20

PAA-Rho1

0 4000

0

3000

11

2000

1000

200

600

800

o

-1

Temperature ( C)

Wavenumber, cm

12 d)

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c)

14

Figure 1. Characterization data of polymeric sensors; (a) FTIR, (b) TGA, (c) SEM (PAA),(d) SEM (PAA-Rho3)

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15 16 17 18 19 20 21 22 23 24 25

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400

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10

In a similar manner to other rhodamine derivatives, polymeric sensors PAA-Rho1-PAA-Rho4 remained colorless and fluorescence inactive in the DMSO solution. This indicates that the spirolactam form of polymeric sensors predominantly existed in either low or high concentration and was confrimed by the sharp signals in the aromatic protons. Ion-responsive properties of polymeric sensors are firstly investigated by monitoring the fluorescent spectra changes in the mixed organic solutions produced by 3+

2+

+

+

+

2+

2+

2+

2+

2+

2+

2+

2+

3+

addition of various metal ions, Au , Hg , Na , K , Ag , Mg , Ca , Pb , Co , Ni , Cu , Zn , Cd , Al , 3+

3+

3+

Cr and Fe . Upon addition of 1 µM of cations to a solution of polymeric sensors, only Au led to the appearance of a new emission band centered at 590 nm which indicated the opening of the spirolactam 3+

ring in polymeric sensors on Au

coordinationas demonstrated in Figure 2. Remarkable fluorescence

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enhancements have shown that the highest selectivity and sensitivity for Au detection were belong to PAA-Rho3 when compared to other polymerice sensors. This could be explained by the suitable distance, steric hindrance, and the soft property of the receptor structure (PAA-Rho3) to form a 3+

complex with Au . In addition, the excitation of the initial solution of polymeric sensors at 520 nm wavelength did not show any significant emission over the range from 530 to 700 nm (Figure 2). This strongly supports the facts that in absence of metal ions the receptor remains in the spirolactum form, and the non-existence of the highly conjugated xanthene form results in the suppression of emission in

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1 2 3 4 5 6 7 8

the above-mentioned region.

9 a)

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300

PAA-Rho3 3+ Au 2+ Hg + Na + K + Ag 2+ Mg 2+ Ca 2+ Pb 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Cd 3+ Al 3+ Cr 3+ Fe

M AN U

250

Intensity

200 150 100

0 550

TE D

50

600

650

10 11

AC C

b)

EP

Wavelength (nm)

12

700

10

ACCEPTED MANUSCRIPT

1

Figure 2. (a) Fluorescence spectral changes of PAA-Rho3 after the addition of 1 µM of various

2

cations. (b) Fluorescence responses of PAA-Rho1-PAA-Rho4 with 1 µM of various cations (0.1 g/L of

3

sensors in 0.01 mol/L of TBAPF6 in DMSO).

4

16

3+

3+

PAA-Rho3 was performed with increasing the concentration of Au . A significant enhancement of absorbance intensity in the 500-580 nm wavelength range was obviously observed as a result of the 3+

Au -induced ring opening of the spirolactam form (Figure 3a). The results are also consistent with the 3+

selectivity from fluorescent titration. Upon the addition of 10 µM Au , there were changes in the

SC

fluorescence spectra of all sensors. Continuous florescence enhancements at 590 nm were monitored (Figure 3b). In addition, the visually color and fluorescence changes were also observed as shown in the 3+

inset of Figure 3 and S6. Moreover, the competition experiment was also carried out by adding Au to the solution of PAA-Rho3 in the present of other metal ions in Figure 4. The results indicate that the 3+

sensing of Au

by PAA-Rho3 is insignificantly affected by these common interfering ions and can be 3+

used as a potential Au -selective chemosensor. a)

0.1

TE D EP

0.2

AC C

Absorbance

0.3

0.0

300

17

RI PT

To further study an inside into the properties of PAA-Rho3 as a chemosensor for Au , the titration of

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5 6 7 8 9 10 11 12 13 14 15

400

500

Wavelength, nm

600

11

ACCEPTED MANUSCRIPT b)

200

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Intensity

300

100

550

600

SC

0 650

700

Wavelength

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1 2

Figure 3. (a) Absorption spectra PAA-Rho3 (0.1 g/L of sensor in 0.01 mol/L of TBAPF6 in DMSO)

3

in the presence of different amounts of Au , Inset: the colour changes of (a) PAA-Rho3 and (b) PAA-

4

Rho3 + Au (c) PAA-Rho3 + other metal ions. (b) Fluorescence spectra (λex=520 nm)of PAA-Rho3 (0.1

5

g/L) under the same conditions, Inset: the colour changes of (a) PAA-Rho3 and (b) PAA-Rho3 + Au (c)

6

PAA-Rho3 + other metal ions.

3+

EP

200

AC C

I-I0 at 578 nm

300

TE D

3+

100

0 +

2+

2+

2+

2+

2+

3+

3+

+ + 2+ 3+ 2+ 2+ 2+ 3+ Au Hg Na K Ag Mg Ca Pb Co Ni Cu Zn Cd Al Cr Fe

7

3+

12

ACCEPTED MANUSCRIPT

1

Figure 4.Fluorescence enhancement response of PAA-Rho3 (0.1 g/L) in 0.01 mol/L of TBAPF6 in

2

DMSO to 1 µM of different metal ions (the black bar portion) and to the mixture of 1 µM different metal

3

ions with 10 µM of Au (the gray bar portion).

3+

4

32 33 34 35 36

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To prepare the polymeric thin film sensor PAA-Rho3-ITO for using in a real system, PAA-Rho3 was modified on ITO substrat through the amide coupling reaction using DCC and DMAP as coupling reagents. After the solvent was evaporated to dryness, a homogeneous, nonfluorescent polymer sensor film was obtained and subsequently washed with THF and DMF to remove unbound PAA-Rho3. The success of the modification was confirmed by FT-IR and AFM. Figure 5 shows the FT-IR spectra before -1

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and after being modified with polymeric sensor. The characteristic peaks at 3528-3290 cm (amide -1

bond) and 2935-2857 cm (rhodamine moities) clearly support that the PAA-Rho3 did bond to the surface.

24

The morphology after immobilization on the ITO substrate was characterized by AFM. The

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result showed that the ultrathin film immobilied on ITO as rougher and patchy films (but complete coverage). The sensing selectivity and sensitivity studies were investigated by open-circuit potentiometry. Changes in potential (∆E) were simultaneously monitored as a function of time at constant zero-current voltage, which performed using the thin film sensors PAA-Rho3 on ITO against 3+

the various concentrations of Au in water solution (0.01 M TBACl as supporting electrolyte) as shown in Figure 7. The decreasing of potentials was observed after dipping PAA-Rho3-ITO into the solution of 3+ 3+

Au

(10

-7

25

In the lowest concentration of

TE D

Au . The same behaviors were observed in the our previous report.

M), the ∆E was suddenly decreased in the first 40 s, followed by a slight decrease until

reaching a steadystate, which also observed in the case of other concentrations. The decreasing of potentials implies the increasing of materials conductivity due to metal-induced efficiency of electron transfer on PAA-Rho3-ITO. This result indicates the increasing of the formation of complexation

EP

3+

between rhodamine moieties and Au

through ion-ion and cation-dipole interactions. In addition,

changing the colours (pale yellow to pink) and fluorescent are observed on the surface area of PAA3+

Rho3 on ITO substrate after exposure to the solution of Au for 3 min (Figure 8), which results from a

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5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

3+

ring-opening form of the spirolactam. We also evaluated the reversibility of the above Au

detection

23

procedure in aqueous solutions treated with aqueous EDTA under basic conditions. As expected, on 3+

dipping into the EDTA solution the fuorescence and colour intensity of PAA-Rho3-ITO plus Au were 3+

3+

quenched. After washing the Au and reexposure to Au , both fuorescence and colour intensity were restored completely. The fuorescence change is reproducible over several cycles of exposure recovery 3+

(Figure S7). According to changes in signaling (∆E and fluorescence emission) upon adding various Au concentration, the limit of detection of PAA-Rho3-ITO for Au is calculated to be 0.10 µM, 3+

26

which is

lower than that observed using uncoated polymeric film PAA-Rho3 (0.43 µM) and the detection time is less than 40 seconds. As compared to PAA-Rho3, PAA-Rho3-ITO sensor gives a lower detection limit 3+

and a higher sensitivity toward Au .

13

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18 16

PAA-Rho3-ITO -1

-CH 2935-2857 cm

12

-1

-NH 3528-3390 cm

10 ITO

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8 6 4 2 0

1 2

3500 3000 -1 Wavenumber, cm

Figure 5. FTIR spectra of the film of PAA-Rho3-ITO on ITO

AC C

EP

TE D

3

4 5

2500

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-2 4000

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Transmittance

14

Figure 6. AFM images of the film of PAA-Rho3-ITO

14

ACCEPTED MANUSCRIPT -4

-0.08 -0.12

200

400 600 Time (sec)

800

1000

SC

0

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E (V vs. Ag/AgCl)

-0.04

-0.16

Figure 7. Potentiometric profiles of PAA-Rho3-ITO in 0.01 M TBACl aqueous solution which various

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1 2 3

3+

10 Au -5 3+ 10 Au -6 3+ 10 Au -7 3+ 10 Au

0.00

3+

concentrations of Au . Plotted data are within 5% deviation from several measurements.

4

TE D

5

9 10 11 12 13 14 15 16 17

EP

8

3+

Figure 8. Fluorescence image of PAA-Rho3-ITO befor and after added Au . The polymer film on the ITO was irradiated with a hand-held UV lamp at 360 nm

AC C

6 7

3+

In addition, our PAA-Rho3-ITO sensor provides a better detection limit (DL) toward Au , easy to recoverand can be used in water as compared to previous reports as listed in Table 1.

33-35

15

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1

3+

Table 1. Selected examples of Au sensors. 3+

Au sensors

Receptor

Rhodamine-based

Modified

Working solvent

reversibility

DL (M)

rhodamine

H2 O

Yes

0.10 × 10

-6

Schiff base and

EtOH: H2O (1:1)

No

0.10 × 10

-6

Polyacrylic acid (PAA-Rho3-ITO) calix[4]arene Schiff base sensor

27

Hybrid

organic–inorganic

nanomaterial sensors

rhodamine

H2 O

28

Thiocoumarin

ACN: H2O (1:1)

29

Pyridine

DMSO: H2O (1:100)

23

Thiocoumarin derivative

Yes

0.83× 10

No

0.11 × 10

No

0.3 × 10

-6

–6

-6

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Pyridine derivatives dyes

2 3

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thiophene

IV.CONCLUSION

We have designed and synthesized the polymeric sensors by grafting rhodamine derivatives as

19

ASSOCIATED CONTENT

20

Supporting Information.

21

Spectroscopic data and compound characterization data including other experiments. This material is available free

22

of charge via the Internet at http://.

23

AUTHOR INFORMATION

24

Corresponding Author

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4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

3+

colorimetric, fluorescent probes into polyacrylic acid skeleton for selective detection of Au ions. New polymeric sensors were simply prepared by amidation reactions between PAA and rhodamine derivatives, which contain various chain lengths and a number of polyamine units with the rhodamine building blocks. Complexation studies showed that PAA-Rho3 exhibited the highest selectivity and 3+

sensitivity towards Au

when compared to the other polymeric sensors. The polymeric sensors were

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non-fluorescence in the spirolactam form and were selectively converted to the fluorescence-active 3+

ring-opened amide form in the presence of Au

ions leading to the fluorescence enhancement and

colorimetric change. Common co-existing metal ions displayed insignificant interference to the 3+

detection of Au . In addition, the polymeric thin film sensors PAA-Rho3-ITO was successfully 3+

3+

probe in water solution. The limit of detection of PAA-Rho3-ITO for Au

EP

prepared and used as Au

was 0.1 µM, lower than that of PAA-Rho3, 0.43 µM, and the detection time was less than 40 seconds. 3+

After sensing Au , the PAA-Rho3-ITO was found to be recovered by dipping in the aqueous EDTA

AC C

solution under basic conditions. Therefore, this approach can be used to fabricate a reversible 3+

polymeric thin film sensor for selective detection of Au .

16

ACCEPTED MANUSCRIPT

1

* E-mail: [email protected] (ChatthaiKaewtong).

2 ACKNOWLEDGMENT

4

This Research was Financially Supported by Mahasarakham University 2015 Copyright of Mahasarakham University

5

and the Thailand Research Fund (RSA5980072) and Center of Excellence for Innovation in Chemistry (PERCH-

6

CIC), Office of the Higher Education Commission, Ministry of Education.

7

REFERENCES

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[1] M. Navarro, Coord. Chem.Rev. 2009, 253, 1619. [2] P. Claus, Appl.Catal. A: Gen. 2005, 291, 222.

M AN U

[3] P. Goodman, Gold Bull. 2002, 35, 21.

[4] M. Suwalsky, R. González, F. Villena, L.F. Aguilar, C.P. Sotomayor, S. Bolognin, P. Zatta, Biochem. Biophys. Res. Commun. 2010, 397(2), 226-231.

[5] D. Parajuli, C. R. Adhikari, H. Kawakita, S. Yamada, K. Ohto, K. Inoue, Bioresour. Technol. 2009, 100, 1000. [6] J. R. Cui, L. F. Zhang, J. Hazard. Mater. 2008, 158, 228. [7] P. F. Sorensen, Hydrometallurgy, 1988, 21, 235.

TE D

[8] C. P. Gomes, M. F. Almeida, J. M. Loureiro, Sep. Purif. Technol. 2001, 24, 35. [9] F. J. Alguacil, P. Adeva, M. Alonso, Gold Bull. 2005, 38, 9. [10] C. Mack, B. Wilhelmi, J. R. Duncan, J. E. Burgess, Biotechnol. Adv. 2007, 25, 264. [11] (a) X. Chen, T. Pradhan, F. Wang, J. S. Kim and J. Yoon,Chem. Rev., 2012, 112, 1910; (b) G. Aragay, J. Pons andA.

EP

Merkoçi, Chem. Rev., 2011, 111, 3433; (c) H. N. Kim,Z. Guo, W. Zhu, J. Yoon and H. Tian, Chem. Soc. Rev., 2011,40, 79; (d) M. Beija, C. A. M. Afonso and J. M. G. Martinho,Chem. Soc. Rev., 2009, 38, 2410; (e) H. N. Kim, M. H. Lee,H. J. Kim, J. S. Kim and J. Yoon, Chem. Soc. Rev., 2008, 37,1465; (f) R. P. Haugland, The Handbook: a guide to fluorescent probes and labeling

AC C

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

RI PT

3

technologies, 10th edn,Molecular Probes, Invitrogen Corp., Karlsbad, CA,2005. [12] (a) J. Y. Kwon, Y. J. Jang, Y. J. Lee, K. M. Kim, M. S. Seo,W. Nam and J. Yoon, J. Am. Chem. Soc., 2005, 127, 10107;(b) Z.-Q. Hu, C.-S. Lin, X.-M. Wang, L. Ding, C.-L. Cui,S.-F. Liu and H. Y. Lu, Chem. Commun., 2010, 46, 3765. [13] (a) V. Dujols, F. Ford and A. W. Czarnik, J. Am. Chem. Soc.,1997, 119, 7386; (b) Y. Xiang, A. Tong, P. Jin and Y. Ju, Org.Lett., 2006, 8, 2863; (c) X. Zhang, Y. Shiraishi and T. Hirai,Org. Lett., 2007, 9, 5039; (d) M. H. Lee, H. J. Kim, S. Yoon,N. Park and J. S. Kim, Org. Lett., 2008, 10, 213; (e) L. Yuan,W. Lin, B. Chen and Y. Xie, Org. Lett., 2012, 14, 432; (f)M. Kumar, N. Kumar, V. Bhalla, P. R. Sharma and T. Kaur,Org. Lett., 2012, 14, 406; (g) P. Xie, F. Guo, D. Li, X. Liu andL. Liu, J. Lumin., 2011, 131, 104; (h) J. F. Zhang, Y. Zhou,J. Yoon, Y. Kim, S. J. Kim and J. S. Kim, Org. Lett., 2010,12, 3852; (i) Y. Zhou, F. Wang, Y. Kim, S. Kim and J. Yoon,Org. Lett., 2009, 11, 4442; (j) C. Yu, J. Zhang, R. Wang andL. Chen, Org. Biomol. Chem., 2010, 8, 5277;

17

ACCEPTED MANUSCRIPT

(k) X. Zeng,L. Dong, C. Wu, L. Mu, S.-F. Xue and Z. Tao, Sens.Actuators, B, 2009, 141, 506; (l) G. He, X. Zhang, C.He,X. Zhao and C. Duan, Tetrahedron, 2010, 66,9762. [14] (a) Y. K. Yang, K. J. Yook and J. Tae, J. Am. Chem. Soc., 2005,127, 16760; (b) W. Shi and H. Ma, Chem. Commun., 2008,1856; (c) J. Wu, I. Hwang, K. Kim and J. Kim, Org. Lett.,2007, 9, 907; (d) X. Zhang, Y. Xiao and X. Qian, Angew.Chem., Int. Ed., 2008, 47, 8025; (e) J. J. Du, J. L. Fan,X. J. Peng, P. P. Sun, J. Y. Wang, H. L. Li and S. G. Sun,Org. Lett., 2010, 12, 476; (f)

3717; (g)J. F. Zhang, C. S. Lim, B. R. Cho and J. S. Kim, Talanta,2010, 83, 658.

RI PT

M. G. Choi, D. H. Ryu,H. L. Jeon, S. Cha, J. Cho, H. H. Joo, K. S. Hong, C. Lee,S. Ahn and S. K. Chang, Org. Lett., 2008, 10,

[15] (a) D. Wu, W. Huang, Z. Lin, Ch. Duan, Ch. He, Sh. Wu andD. Wang, Inorg. Chem., 2008, 47, 7190; (b) H. Yang, Z. Zhou,K. Huang, M. Yu, F. Li, T. Yi and C. Huang, Org. Lett., 2007, 9,4729; (c) M. Suresh, A. Shrivastav, S. Mishra, E. Suresh andA. Das, Org. Lett., 2008, 10, 3013; (d) M. Lee, J. Wu, J. Lee,J. Jung and J. Kim, Org. Lett., 2007, 9, 2501; (e) J. Soh,K.

SC

Swamy, S. Kim, S. Kim, S. Lee and J. Yoon, TetrahedronLett., 2007, 48, 5966; (f) D. Wu, W. Huang, C. Duan, Z. Linand Q. Meng, Inorg. Chem., 2007, 46, 1538; (g) H. Zheng,Z. Qian, L. Xu, F. Yuan, L. Lan and J. Xu, Org. Lett., 2006,8, 859; (h) X.

M AN U

Zhan, Z. Qian, H. Zheng, B. Su, Z. Lan andJ. Xu, Chem. Commun., 2008, 1859; (i) M. Kumar,N. Kumar, V. Bhalla, H. Singh, P. R. Sharma and T. Kaur,Org. Lett., 2011, 13, 1422; (j) J. Huang, Y. Xu and X. Qian, J.Org. Chem., 2009, 74, 2167; (k) V. Bhalla, M. Kumar,P. R. Sharma and T. Kaur, Inorg. Chem., 2012, 51, 2150; (l)C. Wang and K. M.-C. Wong, Inorg. Chem., 2011, 50, 5333;(m) Z. Jin, D.-X. Xie, X.-B. Zhang, Y.-J. Gong and W. Tan,Anal. Chem., 2012, 84, 4253; (n) Y. Zhou, X.-Y. You, Y. Fang,J.-Y. Li, K. Liu and C. Yao, Org. Biomol. Chem., 2010, 8,4819. [16] (a) S. Bae and J. Tae, Tetrahedron Lett., 2007, 48, 5389; (b)Y. Xiang and A. J. Tong, Org. Lett., 2006, 8, 1549; (c)X.

TE D

Zhang, Y. Shiraishi and T. Hirai, Tetrahedron Lett., 2008,10, 4178; (d) M. Zhang, Y. Gao, M. Li, M. Yu, F. Li, L. Li,M. Zhu, J. Zhang, T. Yi and C. Huang, Tetrahedron Lett.,2007, 48, 3709; (e) X. Zhang, Y. Shiraishi and T. Hirai,Tetrahedron Lett., 2007, 48, 5455; (f) J. Mao, L. Wang,W. Dou, X. Tang, Y. Yan and W. Liu, Org. Lett., 2007, 9,4567; (g) K.-S. Moon, Y.-K. Yang, S. Ji and J. Tae,Tetrahedron Lett., 2010, 51, 3290; (h) M. H. Lee, T. V. Giap,S. H. Kim, Y. H. Lee, C. Kang and

EP

J. S. Kim, Chem.Commun., 2010, 46, 1407; (i) A. J. Weerasinghe,C. Schmiesing, S. Varaganti, G. Ramakrishna and E. Sinn,J. Phys. Chem., B, 2010, 114, 9413; (j) Z. Yang, M. She,B. Yin, J. Cui, Y. Zhang, W. Sun, J. Li and Z. Shi, J. Org.Chem., 2012, 77, 1143; (k) L. Zhang, J. Fan and X. Peng,Spectrochim. Acta, Part A, 2009, 73, 398; (l) L. Dong, C.

AC C

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Wu,X. Zeng, L. Mu, S.-F. Xue, Z. Tao and J.-X. Zhang, Sens.Actuators, B, 2010, 145, 433; (m) B. Ma, S. Wu, F. Zeng,Y. Luo, J.Zhao and Z. Tong, Nanotechnology, 2010, 21,195501. [17] (a) Z. Zhou, M. Yu, H. Yang, K. Huang, F. Li, T. Yi andCh. Huang, Chem. Commun., 2008, 3387; (b) K. Huang,H. Yang, Z. Zhou, M. Yu, F. Li, X. Gao, T. Yi andCh. Huang, Org. Lett., 2008, 10, 2557; (c) A. J. Weerasinghe,C. Schmiesing and E. Sinn, Tetrahedron Lett., 2009, 50,6407; (d) Y. Wan, Q. Guo, X. Wang and A. Xia, Anal. Chim.Acta, 2010, 665, 215. [18] (a) A. Chatterjee, M. Santra, N. Won, S. Kim, J. K. Kim,S. B. Kim and K. H. Ahn, J. Am. Chem. Soc., 2009, 131,2040; (b) M. J. Jou, X. Chen, K. M. K. Swamy, H. N. Kim,H.-J. Kim, S.-G. Lee and J. Yoon, Chem. Commun., 2009,7218; (c) O. A. Egorova, H. Seo, A. Chatterjee andK. H. Ahn, Org. Lett., 2010, 12, 401; (d) H. Li, J. Fan, J. Du,K. Guo, S. Sun, X. Liu and X. Peng, Chem. Commun., 2010,46, 1079; (e) M. E. Jun and K. H. Ahn, Org. Lett., 2010, 12,2790.

18

ACCEPTED MANUSCRIPT

[19] (a) H. Zheng, G. Shang, S. Yang, X. Gao and J. Xu, Org. Lett.,2008, 10, 2357; (b) X. Chen, X. Wang, S. Wang, W. Shi,K. Wang and H. Ma, Chem.-Eur. J., 2008, 14, 4719; (c)X. Chen, K.-A. Lee, E.-M. Ha, K. M. Lee, Y. Y. Seo,H. K. Choi, H. N. Kim, M. J. Kim, C.-S. Cho, S. Y. Lee andW. J. Lee, Chem. Commun., 2011, 4373; (d) S. Goswami, S. Paul, A. Manna, RSC Adv., 2013, 3, 10639;(e) S. Goswami, A. Manna, S. Paul, A. K. Maity, P. Saha, C. K. Quah and H.-K. Fun,RSC Adv., 2014, 4, 34572; (f)S. Goswami, A. Manna and S. Paul,RSC Adv., 2014, 4, 21984; (g) S. Goswami, A.

RI PT

Manna, A. K. Maity, S. Paul, A. K. Das, M. K. Das, P. Saha, C. K. Quah and H.-K. Fun, Dalton Trans., 2013, 42, 12844. [20] (a) C. Kaewtong, J. Noiseephum, Y. Uppa, N. Morakot,N. Morakot, B. Wanno, T. Tuntulani and B. Pulpoka, NewJ. Chem., 2010, 34, 1104; (b) C. Kaewtong, B. Wanno,Y. Uppa, N. Morakot, B. Pulpoka and T. Tuntulani, DaltonTrans., 2011, 40, 12578.

SC

[21] (a) D. J. Edlund, D. T. Friesen, W. K. Miller, C. A. Thornton, R. L. Wedel, G. W. Rayfeld and J. R. Lowell, Sens. Actuators, B, 1993, 10, 185; (b) N. Singh, N. Kaur, J. Dunn, R. Behan, R. C. Mulrooney and J. F. Callan, Eur. Polym. J., 2009, 45, 272; (c) S. W. Thomas, G. D. Joly and T. M. Swager, Chem. Rev., 2007, 107, 1339; (d) I. B. Kim, A. Dunkhorst,

M AN U

J. Gilbert and U. H. F. Bunz, Macromolecules, 2005, 38, 4560; (e) L. J. Fan and W. E. Jones, J. Am. Chem. Soc., 2006, 128, 6784; (f) H. N. Kim, Z. Q. Guo, W. H. Zhu, J. Y. Yoon and H. Tian, Chem. Soc. Rev., 2011, 40, 79; (g) J. M. Hu and S. Y. Liu, Macromolecules, 2010, 43, 8315; (h) J. B. Jiang, X. Xiao, P. Zhao and H. Tian, J. Polym. Sci., Part A: Polym. Chem., 2010, 48, 1551; (i) T. Hyakutake, I. Okura, K. Asai and H. Nishide, J. Mater. Chem., 2008, 18, 917; (j) D. Chen, W. Lu, G. Du, L. Jiang, J. Ling and Z. Shen, J. Polym. Sci., Part A: Polym. Chem., 2012, 50, 4191.

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[22] (a) A. R. Hajipour, S. Habibi and A. E. Ruoho, Polym. Adv. Technol., 2009, 20, 1050; (b) A. R. Hajipour, S. Habibi and A. E. Ruoho, J. Appl. Polym. Sci., 2010, 118, 818.

[23] N. Niamsa, C. Kaewtong, V. Srinonmuang, B. Wanno, B. Pulpoka, T. Tuntulani,Polym. Chem., 2013, 4, 3039. [24] J. Kim, J. Cho, P. M. Seidler, N. E. Kurland, V. K. Yadavalli. Langmuir., 2010, 26 (4), 2599.

EP

[25] (a) C. Kaewtong, G. Jiang, Y. Park, A. Baba, T. Fulghum, B. Pulpoka and R. Advincula, Chem. Mater., 2008, 20, 4915. (b) C. Kaewtong, N. Niamsa, Pulpoka, T. and Tuntulani, RSC Adv., 2014, 4, 52235. [26] (a) L. Chen, W. Lu, X. Wang and L. Chen, Sens. Actuators, B, 2013, 182, 482. (b) Z. Yuan, N. Cai, Y. Du, Y. He and

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

E. S. Yeung, Anal.Chem., 2014, 86, 419. [27] S. Memon, A. A. Bhatti, A. A. Bhatti, Ü. Ocak, M. Ocak, J. Iran. Chem. Soc.2016, 13, 2275. [28] J. E. Park, M. G. Choi, S.-K. Chang, Inorg. Chem., 2012, 51, 2880. [29] J. Yang, J. Li, P. Hao, F. Qiu, M. Liu, Q. Zhang,D. Shi, Dyes Pigm. 2015, 116, 97.

ACCEPTED MANUSCRIPT Highly Selective Detection of Au3+ Using Rhodamine-based Modified Polyacrylic acid (PAA)Coated ITO Chatthai Kaewtong,*1 Sastiya Kampaengsri,1 Burapol Singhana2 and Buncha Pulpoka3

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Polymeric sensors were designed and synthesized for selective detection of Au 3+ ions. Polymeric thin film sensors PAA-Rho3-ITO was prepared and used as Au3+ probe in water. Reversible process was done by treating with aqueous EDTA under basic conditions The limit of detection of PAA-Rho3-ITO for Au 3+ is calculated to be 0.10 µM. The detection time is less than 10 seconds.

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• • • • •