Synthesis and characterization of coordination polymer nanoparticles as radioisotope tracers

Applied Radiation and Isotopes 85 (2014) 19–22

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Synthesis and characterization of coordination polymer nanoparticles as radioisotope tracers Min-Seok Oh a, Sung-Hee Jung b, Seong-Ho Choi a,n a b

Department of Chemistry, Hannam University, Daejeon 305-811, Republic of Korea Division of Radioisotope R&D, Korea Atomic Energy Research Institute, Daejeon 305-600, Republic of Korea

art ic l e i nf o

a b s t r a c t

Article history: Received 3 September 2012 Received in revised form 27 October 2013 Accepted 7 November 2013 Available online 4 December 2013

Coordination polymer nanoparticles (NPs) with gamma-emitting nuclide (Au-198), 411 keV, 675 keV, 822 keV and 1087 keV were prepared by coordination polymerization of the radioisotope Au3 þ ions and 1,4-bis(imidazole-1-ylmethyl)benzene in an aqueous solution at room temperature for 3 h. Here, the radioisotope Au3 þ ions were prepared by dissolution of Au-198 foil, which was prepared by neutron irradiation from the HANARO reactor, in KCN aqueous solution. The successful synthesis of the radioisotope coordination polymer NPs with 5 70.5 nm was confirmed via UV–vis spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDXS), Thermogravimetric analysis (TGA), and Gamma spectroscopy analysis. The synthesized radioisotope coordination polymer NPs can be used as radiotracers in science, engineering, and industrial fields. Published by Elsevier Ltd.

Keywords: Coordination polymer nanoparticles Gamma-emitting nuclide Radioisotope Au3 þ ions 1,4-Bis(imidazole-1-ylmethyl)benzene

1. Introduction Metal–organic coordination polymers contain metal ions linked by coordinated (organic) ligands into an infinite array (Vollmer and Nake, 2011). This is a general term that incorporates a variety of architectures ranging from simple one-dimensional chains with small ligands to large frameworks like metal–organic frameworks (MOFs) (Noroa et al., 2009). Generally, the formation process proceeds automatically, and therefore is called a self-assembly process (Robin and Fromm, 2006). There are many methods for the preparation of nano-materials including hydrothermal and solvothermal methods (Wu et al., 2003); microwave–solvothermal synthesis (Vadivel Murugan et al., 2001); microwave synthesis (Marquardt et al., 2011); magneticfield-assisted hydrothermal method (Hu et al., 2011); sol–gel process (Oh et al., 2006); electrochemically induced sol– gel process (Miao et al., 2002); microemulsion (Ji et al., 1999) and reverse micelle/microemulsion methods (Moulik et al., 1999); homogeneous precipitation method (Liu et al., 2007); cluster growth method (Folch et al., 2005); chemical vapor deposition method (Liu et al., 2006); vapor–liquid–solid process (Johansson et al., 2006); soft chemical method (Vayssieres, 2003); electrophoretic deposition method (Liu et al., 2003); electrochemical fabrication method (Kim et al., 2008a, 2008b); chemical reduction method (Elkins et al., 2003); electrolysis of metal salts (Yin et al.,

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Corresponding author. Tel.: þ 82 42 629 8824; fax: þ82 42 629 8810. E-mail addresses: [email protected] (S.-H. Jung), [email protected] (S.-H. Choi).

0969-8043/$ - see front matter Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.apradiso.2013.11.026

2003); rapid expansion of supercritical solvents (Sun et al., 2001); photoreduction of metal ions (Kim et al., 2008c; Oh et al., 2008; Ryu et al., 2009; Chae et al., 2010; Bae et al., 2010); microwave plasma synthesis (Chau et al., 2005); sonochemical method (Alavi and Morsali, 2010); and mechanochemical process (Keskinen et al., 2001). However little has been reported on nano-materials prepared by coordination polymerization using metal ions and organic ligands. Specially, synthesis of the radioactive nano-materials has not been reported using radioactive nuclide and organic ligands via coordination polymerization until now, to our knowledge. In a previous paper (Jung et al., 2010), we firstly synthesized the radioisotope NPs with core–198Au shell–silica by neutron irradiation from the HANARO reactor. These core–shell radioisotope NPs have good physical and mechanical properties because of SiO2 shells in high energy gamma environments. As a result, the core–shell radioisotope NPs can be used as tracers for long periods at high temperature. However, the synthesis method of core–shell radioisotope NPs is complicated since it has a multi-step procedure and cannot produce large amounts of radioisotope NPs. We also prepared core–shell radioisotope NPs with multi-gammaemitting nuclide by neutron irradiation for the HANARO reactor. The synthesis method of the core–shell radioisotope NPs with multi-gamma-emitting nuclide is also very complicated because of the same reason as described above. Therefore, an easy and simple synthesis method is needed to prepare radioisotope NPs in order to be used as radiotracers in various fields, such as science field, engineering field, and industrial field. In this study, radioisotope coordination polymer NPs with Auions–ligands framework were firstly synthesized by coordination

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polymerization of the radioisotope Au3 þ ions, which is prepared by dissolution of Au-198 isotope in KCN aqueous solution after neutron irradiation in the HANARO reactor, and 1,4-bis(imidazole1-ylmethyl)benzene at room temperature for 3 h. To confirm the successful synthesis of radioisotope coordination polymer NPs, the prepared radioisotope NPs were characterized by UV–vis spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometry (EDAX), Thermogravimetric analysis (TGA), Inductively Coupled plasma (ICP), and Gamma spectroscopy.

2. Materials and methods

2.4. Characteristics of coordination polymer NPs with gamma-emitting nuclide (Au-198) UV–vis spectra were measured using a Shimadzu UV-3101PC digital spectrophotometer (Kyoto, Japan) in a 1 cm quartz cuvette. The particles' sizes and morphologies were analyzed by HR-TEM (JEOL, JEM-2010F, Japan). An energy dispersive X-ray spectrometer (EDXS) attached to the HR-TEM was used to analyze their chemical compositions. Mean diameters and size distributions were determined by elastic light scattering (ELS, ELS-8000, Otsuka Co., Japan). The gamma spectrum of the prepared NPs was measured with a HPGe detector (EG&G Ortec, 25% relative efficiency, FWHM 1.85 keV at 1332 keV of 60Co) coupled to a 16K-multichannel analyzer.

2.1. Materials Au foil (0.005  25  25 mm3, 99.98%, The Nilaco Corporation, Tokyo, Japan), Imidazole (Sigma-Aldrich Korea, Seoul, Korea), NaH (60% in oil, Sigma-Aldrich Korea, Seoul, Korea), dimethylformamide (Sigma-Aldrich Korea, Seoul, Korea), dichloromethane (Sigma-Aldrich Korea, Seoul, Korea), a,a′-dichloro-p-xylene (TCI, Tokyo, Japan), and KCN (TCI, Tokyo, Japan) were obtained and used for treatment. Water was purified in a Milli-Q plus water purification system (Millipore Co. Ltd. USA) to a final resistance of 18.2 MΩ cm  1 and degassed prior to each measurement. Other chemicals were of reagent grade.

2.2. Synthesis of the 1,4-bis((1H-imidazole-1-yl)methyl)benzene 1,4-Bis((1H-imidazole-1-yl)methyl)benzene (denoted diimidazole) was synthesized by the reaction of imidazole (10 mmol) and a,a′-dichloro-p-xylene (5.0 mmol) in DMF (100 mL) for 6 h at room temperature. Yields: 86 wt%. 1H NMR (ppm): CH 7.74 ppm (imidazole), CH 7.11 ppm (benzene), –CH2– 5.46 ppm (methylene); FTIR: 3200 cm  1 (aromatic C–H stretching), 2700 cm  1 (C–H stretching); and GC–MAss (FID): m/z: 238.12.

2.3. Synthesis of coordination polymer nanoparticles (NPs) with gamma-emitting nuclide (Au-198) The coordination polymer NPs with gamma-emitting nuclide (Au-198) were synthesized as shown in Fig. 1. First, 197-Au foil (17 mg, 11.6 mmol) was irradiated with neutrons in the nuclear research reactor of the Korea Atomic Energy Research Institute, HANARO (flux: 2.863  1013/cm2 s) resulting in activated Au-198 radioisotopes within the NPs. After then, the radioisotope Au-198 was added into 1.0 M KCN solution to form KAu(CN)2 salts at 60 1C for 4 h. Diimidazole (10 mg, 23.2 mmol) was added into the KAu(CN)2 solution with stirring (3500 rpm) for 30 min at room temperature. After 15 days, the coordination polymer NPs were characterized as solid state form. Yields:  100 wt%.

3. Results and discussion Fig. 2 illustrates the UV–vis spectra of the Au NPs and coordination polymer NPs. Absorption bands around 526 nm for the Au NPs and around 410 nm for the coordination polymer NPs were observed. Both samples showed their expected, typical plasma resonance bands, indicating successful NPs synthesis by γ-radiation and coordination polymerization. No absorption band for Au3 þ ions and bisimidazole at 350–600 nm, corresponding to longitudinal plasmon resonances of the particles, was observed. The oxidized Au3 þ ions can be reduced by electrons generated from diimidazole oxidation during coordination polymerization as shown in Eqs. (1) and (2). However, the plasma peak due to nanoparticles of Au NPs prepared by radiation-induced reduction (Jung et al., 2010, 2012) and coordination polymer NPs with metal ion–organic ligands framework was different as shown in Fig. 2. This means that the metal ions–ligands framework NPs were successfully synthesized by coordination polymerization. Au3 þ þ3e  -Au0

(1)

Au0-Au2-···Aun-···Auagg

(2)

Fig. 3 shows the radioisotope NPs with Au ions–ligands framework prepared by coordination polymerization of radioisotope Au-198 ions and diimidazole in an aqueous solution at room temperature. The TEM image of these particles shows a broad size distribution of particles of below ca. 5 70.5 nm (Fig. 3). Their ELS data show two size distribution regions, due to primary radiation NPs and secondary aggregations of the primary particles. Fig. 4 exhibits the TGA curves of the coordination polymer NPs with Au ions–ligands framework by coordination polymerization. The first weight loss from 50 1C to 206 1C for the coordination polymer NPs was caused by the moisture loss because of the hydrophilic properties due to Au ions–diimidazole framework. The second weight loss due to dissociation of metal and ligands at 207–336 1C occurred. The third and fourth weight losses from 336 1C to 668 1C occurred due to disappearance of diimidazole

Fig. 1. Schematic preparation procedure of the radioisotope coordination polymer NPs with Au ions–ligands framework.

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ligands. The residue amount of the coordination polymer NPs after TGA analysis was about 50%. And also, the Au ratio (%) in radioisotope coordination polymer NPs was measured at 40.4% by using ICP–AES. This means that the radioisotope coordination polymer NPs with Au ions–ligands framework were successfully synthesized by coordination polymerization using radioisotope Au-198 ions, which is prepared by neutron irradiation in the HANARO reactor. Fig. 5 shows the gamma spectrum of radioisotope coordination polymer NPs with Au ions–ligands framework prepared by coordination polymerization. Their recorded spectrum (Fig. 5) shows peaks attributable only to Au-198 with 411 keV, 675 keV, 822 keV and 1087 keV. As a result, the radioisotope coordination polymer NPs with metal ions–ligands framework are successfully synthesized by coordination polymerization using diimidazole and radioisotope Au-198 ions, which is prepared by neutron irradiation in the HANARO reactor. Fig. 4. TGA curves of the radioisotope coordination polymer NPs with Au ions–ligands framework.

Fig. 2. UV–vis spectra of the Au NPs, Au3 þ ions, diimidazole, and radioisotope coordination polymer NPs with Au ions–ligands framework.

Fig. 5. Gamma spectrum of the radioisotope coordination polymer NPs with Au ions–ligands framework.

Fig. 3. TEM images of the radioisotope coordination polymer NPs with Au ions–ligands frameworks.

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4. Conclusion Radioisotope coordination polymer NPs were prepared by coordination polymerization of the radioisotope Au3 þ ions and diimidazole at room temperature for 3 h for the use as radiotracers. The prepared radioisotope coordination polymer NPs with 5–7 nm showed gamma emission from radioactive Au-198 with 411 keV, 675 keV, 822 keV and 1087 keV. The synthesized radioisotope coordination polymer NPs could be used as radiotracers in science field, engineering field, industrial field, etc. The other coordination polymer NPs with gamma emitting nuclide (Ga3 þ , Zn2 þ , etc.) are in progress. Acknowledgment This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (2012M2B2A4029347). References Alavi, M.A., Morsali, A., 2010. Ultrason. Sonochem. 17, 132–138. Bae, H.B., Ryu, J.H., Byun, B.S., Jung, S.H., Choi, S.H., 2010. Curr. Appl. Phys. 10, S44–S50. Chae, J.H., Jung, S.H., Choi, S.H., 2010. Curr. Appl. Phys. 10, S97–S101. Chau, J.L.H., Hsu, M.-K., Hsieh, C.-C., Kao, C.-C., 2005. Mater. Lett. 59, 905–908. Elkins, K.E., Vedantam, T.S., Liu, J.P., Zeng, H., Sun, S., Ding, Y., Wang, Z.L., 2003. Nano Lett. 3, 1647–1649. Folch, B., Larionova, J., Guari, Y., Guérin, C., Reibel, C., 2005. J. Solid State Chem. 178, 2368–2375. Hu, Y.M., Zhu, M.Y., Li, Y., Jin, H.M., Zhu, Z.Z., 2011. Mater. Sci. Forum 688, 148–152.

Ji, M., Chen, X., Wai, C.M., Fulton, J.L., 1999. J. Am. Chem. Soc. 121, 2631–2632. Johansson, J., Wacaser, B.A., Dick, K.A., Seifert, W., 2006. Nanotechnology 17, S355. Jung, J.H., Jung, S.H., Kim, S.H., Choi, S.H., 2012. Nucl. Eng. Technol. 44, 971–976. Jung, S.H., Kim, K.I., Ryu, J.H., Choi, S.H., Kim, J.B., Moon, J.H., Jin, J.H., 2010. Appl. Radiat. Isot. 68, 1025–1029. Keskinen, J., Ruuskanen, P., Karttunen, M., Hannula, S.P., 2001. Appl. Organomet. Chem. 15, 393–395. Kim, H.J., Choi, S.H., Oh, S.H., Woo, J.C., Kim, I.L., 2008a. J. Nanosci. Nanotechnol. 8, 4962–4967. Kim, H.J., Choi, S.H., Lee, K.P., Gopalan, A., Oh, S.H., Woo, J.H., 2008b. Ultramicroscopy 108, 1360–1364. Kim, S.J., Oh, S.D., Lee, S., Choi, S.H., 2008c. J. Ind. Eng. Chem. 14, 449–456. Liu, C.H., Zapien, J.A., Yao, Y., Meng, X.M., Lee, C.S., Fan, S.S., Lifshitz, Y., Lee, S.T., 2003. Adv. Mater. 15, 838–841. Liu, J.Z., Yan, P.X., Yue, G.H., Kong, L.B., Zhuo, R.F., Qu, D.M., 2006. Mater. Lett. 60, 3471–3476. Liu, Y., Jian-er, Z., Larbot, A., Persin, M., 2007. J. Mater. Process. Technol. 189, 379–383. Marquardt, D., Vollmer, C., Thomann, R., Steurer, P., Mülhaupt, R., Redel, E., Janiak, C., 2011. Carbon 49, 1326–1332. Miao, Z., Xu, D., Ouyang, J., Guo, G., Zhao, X., Tang, Y., 2002. Nano Lett. 2, 717–720. Moulik, S.P., De, G.C., Panda, A.K., Bhowmik, B.B., Das, A.R., 1999. Langmuir 15, 8361–8367. Noroa, S.H., Kitagawa, S., Akutagawa, T., Nakamura, T., 2009. Prog. Polym. Sci. 34, 240–279. Oh, S.D., Lee, S., Choi, S.H., Lee, I.S., Lee, Y.M., Chun, J.H., Park, H.J., 2006. Colloids Surf. A 275, 228–233. Oh, S.D., Kim, M.R., Choi, S.H., Chun, J.H., Lee, K.P., Gopalan, A., Hwang, C.K., Kim, S.H., Oh, J.H., 2008. J. Ind. Eng. Chem. 14, 687–692. Robin, A.Y., Fromm, K.M., 2006. Coord. Chem. Rev. 250, 2127–2157. Ryu, J.H., Jung, S.H., Sim, K.S., Choi, S.H., 2009. Appl. Radiat. Isot. 67, 1449–1453. Sun, Y.-P., Atorngitjawat, P., Meziani, M.J., 2001. Langmuir 17, 5707–5710. Vadivel Murugan, A., Sonawane, R.S., Kale, B.B., Apte, S.K., Kulkarni, A.V., 2001. Mater. Chem. Phys. 71, 98–102. Vayssieres, L., 2003. Adv. Mater. 15, 464–466. Vollmer, C., Nake, C. Janiak, 2011. Coord. Chem. Rev. 255, 2039–2057. Wu, C., Xie, Y., Wang, D., Yang, J., Li, T., 2003. J. Phys. Chem. B 107, 13583–13587. Yin, B., Ma, H., Wang, S., Chen, S., 2003. J. Phys. Chem. B 107, 8898–8904.