Selective Recognition of Hg2+ ion in Water by a Functionalized Metal

Feb 20, 2018 - A metal–organic framework (MOF)-based highly selective and sensitive probe (UiO-66@Butyne) for the detection of Hg(II) ion has been d...
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Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX

Selective Recognition of Hg2+ ion in Water by a Functionalized Metal−Organic Framework (MOF) Based Chemodosimeter Partha Samanta,† Aamod V. Desai,† Shivani Sharma,† Priyanshu Chandra,† and Sujit K. Ghosh*,†,‡ †

Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune 411 008, India Centre for Research in Energy & Sustainable Materials, IISER Pune, India

‡

S Supporting Information *

suitability for real-time application. These shortcomings have necessitated the urgent development of new efficient Hg2+ sensors. In recent years, metal−organic frameworks (MOFs) have emerged as a promising and unique class of materials with extended crystalline and porous architecture.7 MOFs have been synthesized from metal nodes and organic struts, wherein the organic linker can be functionalized in accordance with the targeted applications. Because of their large surface area, tunable porosity, and functionality, MOFs have emerged as front-runners as target-specific guest-accessible host systems. On the basis of such host−guest chemistry, MOFs have been employed in the field of gas and solvent separation, drug delivery, catalysis, sensing application, etc.8 Detection of Hg2+ ion using MOFs has recently been investigated with plenty of room for improvement in terms of both control over selectivity/sensitivity and applicability under real-time conditions.9 Most of the MOFs for Hg2+ sensing and trapping that have been reported to date are based on chemosensors, and they can be classified as two types: (1) having nitrogen centers or amine groups, which can coordinate to Hg2+, and (2) sulfur-rich probes, where Hg2+ can bind strongly to the sulfur center due to soft−soft interaction between them (Hg···S interaction) to produce the signal. Despite having reasonable sensitivity, the aforementioned probes have certain inherent drawbacks: (1) both amines and sulfides can undergo aerial oxidation during long-time storage; (2) on the other hand, sulfur-based probes cannot provide a suitable response in a sulfur-rich environment because of the presence of mercury in great quantity.10 To overcome these difficulties, we have adopted the chemodosimeter-based approach, which is devoid of the presence of any amine or sulfur functionality. In the case of the chemodosimeter, the target analyte reacts with dosimeter molecules (probes) in an irreversible fashion (unlike chemosensors) to provide permanent signals.11 As a consequence, it has been observed that both the sensitivity and selectivity of chemodosimeters toward the analyte are high in comparison to those of chemosensors. Consequently, we sought to develop an alkyne-functionalized MOF-based chemodosimeter for the detection of Hg2+ ion (Scheme 1), based on the knowledge that Hg2+ ions react with alkyne groups via oxymercuration reaction in the presence of water.10,12 To the best of our knowledge, reaction-based detection of Hg(II) in an aqueous medium has not been reported in the regime of MOF to date.

ABSTRACT: A metal−organic framework (MOF)-based highly selective and sensitive probe (UiO-66@Butyne) for the detection of Hg(II) ion has been developed. To the best our knowledge, this is the foremost example of a chemodosimeter-based approach to sense Hg(II) ion using a MOF-based probe. The chemical stability of UiO-66@ Butyne renders the sensitive detection of Hg2+ ion in an aqueous phase. UiO-66@Butyne has been found to be selective for Hg(II) ions even in the presence of other metal ions.

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nvironmental pollution due to heavy-metal (mercury, lead, arsenic, and cadmium) ions is becoming a huge threat to human life and other biological species because of their high toxicity and carcinogenicity.1 Among these heavy metals, mercury ion (Hg2+) is one of the most poisonous and widespread environment pollutants because it easily reacts with various biomolecules, causing several deadly diseases like acrodynia (pink disease), minamata, and Hunter−Russell syndrome, even at very low concentration.2 Extensive use of Hg2+ across different fields (batteries, dental amalgams, electrical apparatuses, etc.) has led to remarkable disposal and contamination of the environment. According to the U.S. Environmental Protection Agency (EPA), the estimated release of Hg2+ into the environment has reached ∼7500 tons per year.3 Contamination of Hg2+ in natural water resources, especially in drinking water, is one of the most threatening issues. Considering the deleterious consequences of mercury, it has become imperative to urgently design efficient sensors that can detect Hg2+ ion at very low concentration in an aqueous medium. Until now, numerous efforts have been made to develop efficient sensors for Hg2+ ion. Different kinds of techniques such as liquid chromatography, chemiluminescence, colorimetric detection, inductively coupled plasma mass spectrometry, Xray absorption spectroscopy, and anodic stripping voltammetry have been employed for the detection of toxic mercury ion.4 Among these techniques, chemiluminescence has attracted considerable attention over the others because of its operational simplicity, instant response, cost effectiveness, and high sensitivity.5 Prompted by the efficacy of this technique, various types of fluorescent probes have been developed based on organic small molecules, DNA, quantum dots, inorganic− organic hybrid materials, organic polymers, etc.6 However, low water solubility of organic-molecule-based sensors and low water stability of the organic−inorganic hybrid materials hinder their © XXXX American Chemical Society

Received: September 22, 2017

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DOI: 10.1021/acs.inorgchem.7b02426 Inorg. Chem. XXXX, XXX, XXX−XXX

Communication

Inorganic Chemistry

MOF in water and excited at 340 nm to obtain fluorescence spectra in the range of 355−650 nm. Upon excitation at 340 nm, the compound showed smooth emission spectra with a maximum at 537 nm, which was quenched upon the addition of an aqueous Hg(II)-ion solution (Figure 2). This fluorescence

Scheme 1. Detection of Hg(II) Ion in a Water Medium with a Functionalized MOF

For practical applications of any compound as chemical sensory materials, water stability is the primary criteria because, in most of the cases, detection of the targeted analytes has been carried out from wastewater or any other water sources. UiO series MOFs are well-known for high chemical stability arising from its secondary building unit Zr6O4(OH)4(CO2)12.13 Because of the high chemical stability of UiO-66, we have chosen butynefunctionalized UiO-66@Butyne as a potential Hg(II) sensor, which can provide a signal through an irreversible oxymercuration reaction (Figure 1). UiO-66@Butyne is an

Figure 2. Change in the fluorescence spectra of UiO-66@Butyne upon the incremental addition of a Hg(II)-ion solution in a water medium.

change occurs because of the formation of UiO-66@OH, which is relatively less fluorescent, as a result of the oxymercuration reaction between UiO-66@Butyne and Hg(II) ion in water. To examine the structural stability of a Hg(II)-ion-treated phase of UiO-66@Butyne, we did a thorough characterization using the aforementioned techniques. The PXRD pattern of the Hg(II)-ion-treated phase showed that the compound remained crystalline and maintained its framework as a parent compound (Figure S11). A similar thermal stability of this compound was obtained from TGA profiles, which validated retention of the framework integrity (Figure S12). The diminishing peak at ∼2950 cm−1 in IR spectroscopy indicated a loss of alkyne functionality upon treatment with Hg(II) ion (Figure 3a). In addition to IR spectroscopy, we have performed 13C-NMR spectroscopy of Hg(II)-ion-treated UiO-66@Butyne to substantiate the reaction (Figure S13). Furthermore, we performed FESEM to check the morphological stability of UiO-66@Butyne. Both compounds were found to have similar morphology, confirming the similar framework integrity and stability of UiO66@Butyne even after oxymercuration reaction in an aqueous medium (Figure S14). With the desolvated phase of both compounds, low-temperature gas adsorption measurements (N2 at 77 K) were carried out. Because of the presence of a bulky substituent in UiO-66@ Butyne, a very low uptake of N2 gas was observed. In the case of a Hg(II)-ion-treated phase, because of the removal of butyne groups, N2 uptake was enhanced by 10 times compared to UiO66@Butyne (Figure S15). In addition, the Brunauer−Emmett− Teller surface area of UiO-66@Butyne was found to be very negligible, whereas upon reaction with a Hg(II) ion, the surface area increased to 174 m2 g−1. This result also confirmed that oxymercuration reaction occurred inside the pores and the framework integrity was maintained after reaction. Enthused by the above results, we sought to carry out further experiments regarding the detection of Hg(II) ion in an aqueous medium. Here, all of the fluorescence measurements were carried out in the dispersed phase, where 1 mg of MOF has been dispersed in 2 mL of water. At first, we have recorded the fluorescence response of UiO-66@Butyne on the incremental addition of a Hg(II) ion solution in an aqueous medium with 3

Figure 1. Schematic representation of the probable mechanism of Hg(II) sensing in UiO-66@Butyne.

isoreticular MOF to terephthalic acid derived UiO-66. To synthesize UiO-66@Butyne, we first synthesized terephthalic acid having two side chains, ending up with butyne functionalization (BDC@butyne), and then MOF formation was carried out in the solvothermal method with ZrCl4 in N,Ndimethylformamide as the solvent. To check the framework integrity of the thus-prepared UiO-66@Butyne, characterization was carried out with powder X-ray diffraction (PXRD), IR spectroscopy, thermogravimetric analysis (TGA), N2 gas adsorption measurement at 77 K, and field-emission scanning electron microscope (FESEM). The PXRD pattern of UiO-66@ Butyne was found to be crystalline and matched with UiO-66, which indicated that both compounds were isostructural (Figure S7).14 The peak around 2950 cm−1 corresponded to the stretching frequency of C−H (in the −CH2− group) present in the alkyl chain and thus confirmed the presence of butyne groups in the framework (Figure S8).15 In TGA, there was initial loss of ∼20% in the as-synthesized compound because of occluded solvent molecules as guests; upon activation of the compound, we found a very negligible loss up to ∼250 °C (Figure S9). So, we have synthesized water-stable zirconiumbased MOFs bearing butyne groups as active sites for Hg(II) detection, instead of conventionally adopted functionality like amine groups or sulfur groups. To check the activity of UiO-66@ Butyne toward the Hg(II) ion, we have dispersed desolvated B

DOI: 10.1021/acs.inorgchem.7b02426 Inorg. Chem. XXXX, XXX, XXX−XXX

Communication

Inorganic Chemistry

approaches like coordination of the targeted metal ion to the active sites of MOFs. Encouraged by this result, we thought to examine the efficacy of the probe to sense Hg2+ ion in the presence of other metal ions. In a typical experiment, MOF was dispersed in water, and to that a particular metal ion was added; then the fluorescence was measured after 3 min of equilibration time. Later Hg2+ ion was added to the solution, and again the fluorescence of the solution was measured. As expected, the respective metal ions did not show much change, but the fluorescence intensity of the solution was quenched upon the addition of Hg2+ ion (Figure S22). So, this experiment proves that our MOF-based system can sense Hg(II) ion with high sensitivity and selectivity even in the presence of concurrent metal ions. Further, energy-dispersive absorption X-ray analysis was carried for UiO-66@Butyne and the Hg(II)-ion-treated phase of UiO-66@Butyne, which revealed the presence of carbon, oxygen, and zirconuim in both compounds, which also ruled out the presence of mercury (Figures S23 and S24). Also, the mechanism was validated using a control experiment with a diester derivative of the ligand (Figure S25). In conclusion, we have synthesized a stable and butynefunctionalized MOF via ligand modulation that is analogous to UiO-66. Rendering the butyne functionality, we have achieved the selective detection of Hg(II) ion in an aqueous medium via oxymercuration reaction. Although a few MOF-based Hg(II) ion sensors have been reported in recent days, a reaction-based sensor has not been reported to date in the MOF regime. Irreversible reaction between the Hg(II) ion and butyne group provides selectivity as well as high sensitivity with a detection limit of 10.9 nM. We believe that this work will stimulate research in the field of MOF-based Hg(II) ion sensing in a chemodosimeter approach and will also motivate to the fabrication of MOF-based probes for other toxic heavy metals.

Figure 3. (a) IR spectra of UiO-66@Butyne (wine red) and after Hg(II) ion treatment (green). (b) Extent of the fluorescence response of UiO66@Butyne toward various metal ions.

min of equilibration time. It has been found that, upon an increase in the concentration of the Hg(II) ion in the solution, the intensity of the photoluminescence profile was quenched (Figure S17). Also, in a kinetic study of UiO-66@Butyne in the presence of a Hg(II) ion, an instant change in the intensity of the compound was observed (Figure S18). This kind of rapid and high quenching ability of the MOF was observed because of its fast and strong interaction with analyte molecules. The limit of detection for the probe was calculated according to the previous reports and found to be 10.9 nM (Figure S19 and Table S2).16 According to the U.S. EPA, the toxicity level of Hg2+ ion is 10 nM in drinking water. So, the LOD of UiO-66@Butyne lies close to the range permitted by the U.S. EPA and is one of the best in the MOF regime reported to date.17 Finally, we have recorded photoluminescence spectra of UiO-66@OH (analogous of UiO66@Butyne) before and after the addition of Hg(II) ion to check the effect of butyne groups. We did not find any response of UiO66@OH toward Hg2+ ion indicating the role of a butyne group here (Figure S20). Similarly, only ligand did not show any noticeable response toward Hg(II) ion, which clearly explains the importance of the ordered framework in this case (Figure S20). Here the restriction of C−O bond rotation due to the presence of bulky butyne groups can be attributed to the origin of fluorescence in UiO-66@Butyne; thus, removal of the butyne groups via oxymercuration reaction results in a signal change.18 Apart from sensitivity, high selectivity is also a very important criterion for a good sensory material to be used. Keeping this point in mind, we recorded the response of UiO-66@Butyne toward other metal ions (Ba2+, Cd2+, Co2+, Cu2+, Zn2+, Cr3+, Fe3+, Mg2+, Mn2+, Ni2+, and Sr2+) having similar concentration as Hg2+ ion in similar way. No such response in the fluorescence spectra was observed in the presence of other cations in an aqueous medium (Figure 3b). So, the reaction-based approach to detect Hg2+ ion made the probe highly selective and sensitive over other

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.7b02426. Experimental details, 1H and 13C NMR spectra, PXRD data, TGA plots, FT-IR spectra, FESEM images, gas adsorption profiles, standard deviation, IR spectra, elemental mapping, quenching efficiency, and fluorescence spectra (PDF)

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Aamod V. Desai: 0000-0001-7219-3428 Shivani Sharma: 0000-0002-5466-8159 Sujit K. Ghosh: 0000-0002-1672-4009 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS P.S. and P.C. are thankful to UGC and DST INSPIRE, respectively, and A.V.D. and S.S. are thankful to IISER Pune for a fellowship. We are grateful to IISER Pune and DST-SERB (Grant EMR/2016/000410) for research facilities and financial support, respectively. C

DOI: 10.1021/acs.inorgchem.7b02426 Inorg. Chem. XXXX, XXX, XXX−XXX

Communication

Inorganic Chemistry

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1268. (d) Cui, Y.; Yue, Y.; Qian, G.; Chen, B. Luminescent Functional Metal-Organic Frameworks. Chem. Rev. 2012, 112, 1126−1162. (e) Sen, S.; Nair, N. N.; Yamada, T.; Kitagawa, H.; Bharadwaj, P. K. High Proton Conductivity by a Metal−Organic Framework Incorporating Zn8O Clusters with Aligned Imidazolium Groups Decorating the Channels. J. Am. Chem. Soc. 2012, 134, 19432−19437. (f) Hu, Z.; Deibert, B. J.; Li, J. Luminescent Metal−Organic Frameworks for Chemical Sensing and Explosive Detection. Chem. Soc. Rev. 2014, 43, 5815−5840. (g) Aguilera-Sigalat, J.; Bradshaw, D. Synthesis and Applications of Metal-Organic Framework−Quantum Dot (QD@MOF) Composites. Coord. Chem. Rev. 2016, 307, 267−291. (h) Yang, H.; Bradley, S. J.; Chan, A.; Waterhouse, G. I. N.; Nann, T.; Kruger, P. E.; Telfer, S. G. Catalytically Active Bimetallic Nanoparticles Supported on Porous Carbon Capsules Derived From Metal−Organic Framework Composites. J. Am. Chem. Soc. 2016, 138, 11872−11881. (i) Yee, K.-K.; Reimer, N.; Liu, J.; Cheng, S.-Y.; Yiu, S.-M.; Weber, J.; Stock, N.; Xu, Z. Effective Mercury Sorption by Thiol-Laced Metal−Organic Frameworks: in Strong Acid and the Vapor Phase. J. Am. Chem. Soc. 2013, 135, 7795− 7798. (j) Zheng, Y.; Sato, H.; Wu, P.; Jeon, H. J.; Matsuda, R.; Kitagawa, S. Flexible Interlocked Porous Frameworks Allow Quantitative Photoisomerization in a Crystalline Solid. Nat. Commun. 2017, 8, XX DOI: 10.1038/s41467-017-00122-5. (9) (a) Zhu, Y.-M.; Zeng, C.-H.; Chu, T.-S.; Wang, H.-M.; Yang, Y.-Y.; Tong, Y.-X.; Su, C.-Y.; Wong, W.-T. A Novel Highly Luminescent LnMOF Film: A Convenient Sensor for Hg2+ Detecting. J. Mater. Chem. A 2013, 1, 11312−11319. (b) Wu, L.-L.; Wang, Z.; Zhao, S.-N.; Meng, X.; Song, X.-Z.; Feng, J.; Song, S.-Y.; Zhang, H.-J. A Metal−Organic Framework/DNA Hybrid System as a Novel Fluorescent Biosensor for Mercury(II) Ion Detection. Chem. - Eur. J. 2016, 22, 477−480. (c) Wu, P.; Liu, Y.; Liu, Y.; Wang, J.; Li, Y.; Liu, W.; Wang, J. Cadmium-Based Metal−Organic Framework as a Highly Selective and Sensitive Ratiometric Luminescent Sensor for Mercury(II). Inorg. Chem. 2015, 54, 11046−11048. (d) Wang, H.-M.; Yang, Y.-Y.; Zeng, C.-H.; Chu, T.S.; Zhu, Y.-M.; Ng, S. W. A Highly Luminescent Terbium−Organic Framework for Reversible Detection of Mercury Ions in Aqueous Solution. Photochem. Photobiol. Sci. 2013, 12, 1700−1706. (e) Wen, L.; Zheng, X.; Lv, K.; Wang, C.; Xu, X. Two Amino-Decorated Metal− Organic Frameworks for Highly Selective and Quantitatively Sensing of Hg(II) and Cr(VI) in Aqueous Solution. Inorg. Chem. 2015, 54, 7133− 7135. (f) Rudd, N. D.; Wang, H.; Fuentes-Fernandez, E. M. A.; Teat, S. J.; Chen, F.; Hall, G. S.; Chabal, Y. J.; Li, J. Highly Efficient Luminescent Metal−Organic Framework for the Simultaneous Detection and Removal of Heavy Metals from Water. ACS Appl. Mater. Interfaces 2016, 8, 30294−30303. (g) Shahat, A.; Elsalam, S. A.; Herrero-Martínez, J. M.; Simó-Alfonso, E. F.; Ramis-Ramos, G. Optical Recognition and Removal of Hg(II) Using a New Self-Chemosensor based on a Modified Amino-Functionalized Al-MOF. Sens. Actuators, B 2017, 253, 164−172. (h) Razavi, S. A. A.; Masoomi, M. Y.; Morsali, A. Double Solvent Sensing Method for Improving Sensitivity and Accuracy of Hg(II) Detection Based on Different Signal Transduction of a Tetrazine-Functionalized Pillared Metal−Organic Framework. Inorg. Chem. 2017, 56, 9646− 9652. (i) Liu, T.; Che, J.-X.; Hu, Y.-Z.; Dong, X.-W.; Liu, X.-Y.; Che, C.M. Alkenyl/Thiol-Derived Metal−Organic Frameworks (MOFs) by Means of Postsynthetic Modification for Effective Mercury Adsorption. Chem. - Eur. J. 2014, 20, 14090−14095. (10) (a) Dong, M.; Wang, Y.-W.; Peng, Y. Highly Selective Ratiometric Fluorescent Sensing for Hg2+ and Au3+, Respectively, in Aqueous Media. Org. Lett. 2010, 12, 5310−5313. (b) Song, F.; Watanabe, S.; Floreancig, P. E.; Koide, K. Oxidation-Resistant Fluorogenic Probe for Mercury Based on Alkyne Oxymercuration. J. Am. Chem. Soc. 2008, 130, 16460− 16461. (11) Eun Jun, M.; Roy, B.; Han Ahn, K. ‘‘Turn-on’’ Fluorescent Sensing with ‘‘Reactive’’ Probes. Chem. Commun. 2011, 47, 7583−7601. (12) Santra, M.; Ryu, D.; Chatterjee, A.; Ko, S.-K.; Shin, I.; Ahn, K. H. A Chemodosimeter Approach to Fluorescent Sensing and Imaging of Inorganic and Methylmercury Species. Chem. Commun. 2009, 2115− 2117. (13) Cavka, J. H.; Jakobsen, S.; Olsbye, U.; Guillou, N.; Lamberti, C.; Bordiga, S.; Lillerud, K. P. A New Zirconium Inorganic Building Brick

REFERENCES

(1) (a) Aragay, G.; Pons, J.; Merkoçi, A. Recent Trends in Macro-, Micro-, and Nanomaterial-Based Tools and Strategies for Heavy-Metal Detection. Chem. Rev. 2011, 111, 3433−3458. (b) Li, M.; Gou, H.; AlOgaidi, I.; Wu, N. Nanostructured Sensors for Detection of Heavy Metals: A Review. ACS Sustainable Chem. Eng. 2013, 1, 713−723. (2) (a) ATSDR. Toxicological Profile for Mercury; U.S. Department of Health and Human Services: Atlanta, GA, 1999; pp 1−696. (b) Fluorescent Chemosensors for Ion and Molecule Recognition; Czarnik, A. W., Ed.; American Chemical Society: Washington, DC, 1992. (3) Regulatory Impact Analysis of the Clean Air Mercury Rule; U.S. Environmental Protection Agency: Research Triangle Park, NC, 2005; EPA-452/R-05-003. (4) (a) Chen, X.; Han, C.; Cheng, H.; Wang, Y.; Liu, J.; Xu, Z.; Hu, L. Rapid Speciation Analysis of Mercury in Seawater and Marine Fish by Cation Exchange Chromatography Hyphenated with Inductively Coupled Plasma Mass Spectrometry. J. Chromatogr. A 2013, 1314, 86−93. (b) Bernaus, A.; Gaona, X.; Esbri, J. M.; Higueras, P.; Falkenberg, G.; Valiente, M. Microprobe Techniques for Speciation Analysis and Geochemical Characterization of Mine Environments: The Mercury District of Almadén in Spain. Environ. Sci. Technol. 2006, 40, 4090−4095. (c) Kanayama, N.; Takarada, T.; Maeda, M. Rapid Nakedeye Detection of Mercury Ions Based on Non-crosslinking Aggregation of Double-Stranded DNA-carrying Gold Nanoparticles. Chem. Commun. 2011, 47, 2077−2079. (d) Chae, M.-Y.; Czarnik, A. W. Fluorimetric Chemodosimetry. Mercury(II) and Silver(I) Indication in Water via Enhanced Fluorescence Signaling. J. Am. Chem. Soc. 1992, 114, 9704−9705. (5) (a) Gupta, A.; Chaudhary, A.; Mehta, P.; Dwivedi, C.; Khan, S.; Verma, N. C.; Nandi, C. K. Nitrogen-Doped, Thiol-Functionalized Carbon Dots for Ultrasensitive Hg(II) Detection. Chem. Commun. 2015, 51, 10750−10753. (b) Ando, S.; Koide, K. Development and Applications of Fluorogenic Probes for Mercury(II) Based on Vinyl Ether Oxymercuration. J. Am. Chem. Soc. 2011, 133, 2556−2566. (c) Venkateswarlu, S.; Yoon, M. Surfactant-free Green Synthesis of Fe3O4 Nanoparticles Capped with 3,4-dihydroxyphenethylcarbamodithioate: Stable Recyclable Magnetic Nanoparticles for the Rapid and Efficient Removal of Hg(II) ions from Water. Dalton Trans. 2015, 44, 18427−18437. (6) (a) Kim, H. N.; Ren, W. X.; Kim, J. S.; Yoon, J. Fluorescent and Colorimetric Sensors for Detection of Lead, Cadmium, and Mercury Ions. Chem. Soc. Rev. 2012, 41, 3210−3244. (b) Nolan, E. M.; Lippard, S. J. Tools and Tactics for the Optical Detection of Mercuric Ion. Chem. Rev. 2008, 108, 3443−3480. (c) Nolan, E. M.; Lippard, S. J. Turn-On and Ratiometric Mercury Sensing in Water with a Red-Emitting Probe. J. Am. Chem. Soc. 2007, 129, 5910−5918. (7) (a) O’Keeffe, M.; Yaghi, O. M. Deconstructing the Crystal Structures of Metal-Organic Frameworks and Related Materials into Their Underlying Nets. Chem. Rev. 2012, 112, 675−702. (b) Schneemann, A.; Bon, V.; Schwedler, I.; Senkovska, I.; Kaskel, S.; Fischer, R. A. Flexible Metal−Organic Frameworks. Chem. Soc. Rev. 2014, 43, 6062− 6096. (c) Kim, C. R.; Uemura, T.; Kitagawa, S. Inorganic Nanoparticles in Porous Coordination Polymers. Chem. Soc. Rev. 2016, 45, 3828− 3845. (d) Peng, G.; Ma, L.; Cai, J.; Liang, L.; Deng, H.; Kostakis, G. E. Influence of Alkali Metal Cation (Li(I), Na(I), K(I)) on the Construction of Chiral and Achiral Heterometallic Coordination Polymers. Cryst. Growth Des. 2011, 11, 2485−2492. (e) Sindoro, M.; Yanai, N.; Jee, A.-Y.; Granick, S. Colloidal-Sized Metal-Organic Frameworks: Synthesis and Applications. Acc. Chem. Res. 2014, 47, 459−469. (8) (a) He, C.; Liu, D.; Lin, W. Nanomedicine Applications of Hybrid Nanomaterials Built from Metal−Ligand Coordination Bonds: Nanoscale Metal−Organic Frameworks and Nanoscale Coordination Polymers. Chem. Rev. 2015, 115, 11079−11108. (b) Meek, S. T.; Greathouse, J. A.; Allendorf, M. D. Metal-Organic Frameworks: A Rapidly Growing Class of Versatile Nanoporous Materials. Adv. Mater. 2011, 23, 249−267. (c) Horcajada, P.; Gref, R.; Baati, T.; Allan, P. K.; Maurin, G.; Couvreur, P.; Férey, G.; Morris, R. E.; Serre, C. MetalOrganic Frameworks in Biomedicine. Chem. Rev. 2012, 112, 1232− D

DOI: 10.1021/acs.inorgchem.7b02426 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry Forming Metal-Organic Frameworks with Exceptional Stability. J. Am. Chem. Soc. 2008, 130, 13850−13851. (14) Garibay, S. J.; Cohen, S. M. Isoreticular Synthesis and Modification of Frameworks with the UiO-66 Topology. Chem. Commun. 2010, 46, 7700−7702. (15) Sun, Y.; Sun, Q.; Huang, H.; Aguila, B.; Niu, Z.; Perman, J. A.; Ma, S. A Molecular-level Superhydrophobic External Surface to Improve the Stability of Metal−Organic Frameworks. J. Mater. Chem. A 2017, 5, 18770−18776. (16) Desai, A. V.; Samanta, P.; Manna, B.; Ghosh, S. K. Aqueous Phase Nitric Oxide Detection by An Amine-Decorated Metal−Organic Framework. Chem. Commun. 2015, 51, 6111−6114. (17) Yang, J.; Wang, Z.; Li, Y.; Zhuang, Q.; Zhao, W.; Gu, J. Porphyrinic MOFs for Reversible Fluorescent and Colorimetric Sensing of Mercury(II) Ions in Aqueous Phase. RSC Adv. 2016, 6, 69807− 69814. (18) Mahato, P.; Saha, S.; Das, P.; Agarwalla, H.; Das, A. An Overview of the Recent Developments on Hg2+ Recognition. RSC Adv. 2014, 4, 36140−36174.

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DOI: 10.1021/acs.inorgchem.7b02426 Inorg. Chem. XXXX, XXX, XXX−XXX