Chapter V. Carboxylated Pillar[5]arene-Coated Gold Nanoparticles with Chemical Stability and
5.5. Experimental
All reagents and chemicals were purchased from commercial sources and used as received. All reactions were performed under N2 unless otherwise noted. NMR spectra were recorded on a Varian VNMRS 600 spectrometer. Transmission electron microscopy (TEM) was performed on a JEOL JEM-1400 microscope at an acceleration voltage of 80 kV. Sample specimens were prepared by placing a drop of the solution on a carbon-coated Cu grid (200 mesh, EM science). After 30 min, remaining solution on a grid was removed with a filter paper, and the grid was air-dried for 18 h. Dynamic light scattering (DLS) experiments were carried out on a BI-200SM equipped with a diode laser (637 nm, 4 mW). All DLS data were handled on a Dispersion Technology Software (Brookhaven Instruments). Absorption spectra and time-course absorption changes AuNPs at 520 nm were collected on a JASCO V-670 spectrophotometer. The solution of gold nanoparticles were diluted to a desired concentration for the measurement. Fourier transform infrared (FT-IR) spectroscopy was performed on a Varian 670-IR at ATR mode. The sample was freeze dried for the measurement.
CP was synthesized according to the previous literatures.20,21
1H NMR (600 MHz, D2O) δ (ppm): 3.85 (s, 10H), 4.3 (d, 10H), 4.5 (d, 10H), 6.8 (s, 10H).
Synthesis of CM.
To a solution of NaH (9 g) in DMF (40 mL) at 0 °C was added hydroquione (10 g, 90.9 mmol). The solution was stirred for 30 min, and then excess amount of ethyl bromoacetate was added to continue the reaction at room temperature for 4 hr. After quenching the reaction with ice water, the crude was filtered, and recrystallized from a mixture of ethyl acetate/n-hexane (1:6) to give a white powder. The resulting product in THF (200 mL) was added to NaOH solution (20%, 200 mL), and the mixture was refluxed for 20 h. The resulting mixture was concentrated and diluted into water. The solution was acidified with HCl to give precipitate. The product was obtained by filtration, washing with water, and drying under vacuum.
2,2'-[1,4-Phenylenebis(oxy)]diacetic acid; 1H NMR (600 MHz, DMSO-d6) δ (ppm): 4.57 (s, 4H), 6.82 (s,4H), 12.9 (2H). 13C (600 MHz, DMSO-d6) δ (ppm): 65.449, 115.726, 152.556, 170.794.
2,2'-[1,4-Phenylenebis(oxy)]diacetic acid (0.2 g) was dispersed in water (5 mL), and the suspension was dissolved by titrating NaOH solution. CM (sodium 2,2'-[1,4-Phenylenebis(oxy)]diacetate) was obtained by freeze-drying. 1H NMR (600 MHz, D2O) δ (ppm): 4.33 (s, 4H), 6.8 (4H). 13C (600 MHz, D2O) δ (ppm): 67.182, 115.402, 152.094, 176.882.
Preparation of AuNPs
In typical experiment, HAuCl4 (0.01 %) was dissolved in distilled water (10 mL), and refluxed for 10
97
min. To the solution was added carboxylated ligand (CP, CM or C; 1% 0.3 ml H2O). Within 5 min, the color of solution turn wine-red, and the reaction was further allowed for 1 hr. The shape and diameter of AuNPs were characterized by TEM and DLS. The plasmonic characteristic of AuNP was confirmed by UV/vis absorption spectroscopy.
Figure 5.3. 1H NMR spectrum of 2,2'-[1,4-phenylenebis(oxy)]diacetic acid.
Figure 5.4. 13C NMR spectrum of 2,2'-[1,4-phenylenebis(oxy)]diacetic acid.
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Figure 5.5. 1H NMR spectrum of sodium 2,2'-[1,4-phenylenebis(oxy)]diacetate.
Figure 5.6. 13C NMR spectrum of sodium 2,2'-[1,4-phenylenebis(oxy)]diacetate.
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Figure 5.7. UV/vis absorption spectra of the solution of CP-AuNP as-made (black) and after 6 months (red). The result indicates the solution of CP-AuNPs is highly stable without aggregation or precipitation.
Figure 5.8. FT-IR spectrum of CP-AuNP. Fourier transform infrared spectroscopy revealed the presence of C=C stretching of the aromatic ring in the backbone of CP, indicating that CP-AuNP is capped by CP.
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Figure 5.9. TEM image of C-AuNP. TEM analysis corroborates that the dimension of C-AuNP is almost identical to that of CP-AuNP (d ~ 17 nm).
Figure 5.10. Absorption spectra of CP-AuNPs before and after addition of (A) NaCl, (B) HCl, (C) NaOH or (D) CaCl2. In the case of CP-AuNP/CaCl2, the absorption intensity at 520 nm was almost identical to that of before addition, a broad and red-shifted band was appeared, probably implying an aggregation of AuNPs.
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Figure 5.11. Relative stability of CP-AuNP (2 ml, red) and C-AuNP (2 ml, purple) after sequential addition of NaOH (2 μl, 1 M) and HCl (2 μl, 1 M). After scanning the relative absorbance for 200 sec, we added NaOH and followed the absorbance change for 200 sec. Subsequently, we added HCl to the solution, and the time-course analysis for relative absorbance between CP-AuNP and C-AuNP showed clear differences.
5.5. Reference
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Chapter V
Acknowledgement (English version)
I had time to arrange my graduate school life while I was preparing for graduation. I could not believe that my graduate school life have gone so fast. I want to say thank you to many people when I look back at my graduation life. First of all thank you for supporting my family and believing in me. I was able to finish the graduate school life safely because there was a family that supported me and encouraged me.
I really appreciate to Professor Kyoung Taek Kim and Professor Ja-Hyoung Ryu as my supervisors. I was able to graduate safely because my supervisors taught me that I lacked much. I will continue to study and work harder to become a better researcher in the future. I also appreciate to Professor Hoi Ri Moon, Professor Sung You Hong, Professor Young S. Park for giving me a committees. I was able to think about my research and organize it once more with the questions and advice. I would also like to thank Professor Chiyoung Park and Professor Yung-Sam Kim for thinking about me and for taking care of me even though I am in Seoul. And thanks to our polymer synthesis laboratory. I think it's a great luck to meet our lab people in graduate school. We had a very pleasant laboratory life because there were Hyunkyu, Yunju, Arah, Moon Gon, So Ryoung who have been living together since UNIST. Also I thank to my laboratory members, Ji Won Kim, Jeong Eun Song, Hyun Ji Ma, Chae Eun Lee, Yong Beom Kwon, Mi Sun Yoon, Jun Young Kim, Sung Min Ha, Jeong Min Lee, Sul Woo Lee, Hee Lim Lee, Yu Lin Sun, Jun Ho Kwon, Jong Min Kim, every day was precious and happy. I was also very happy to join the graduate school with Hyun Ji Yang, Woo Gyum Kim, Jeena M. T. I think I could complete my degree because I met many people while I was in graduate school and I was able to live happily and thoroughly by receiving help. I would like to thank all the people around me and I will try to be a researcher who is not a shame to go out to society. Thank you again.
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감사의 글 (Korean version)
졸업 준비를 하면서 제 대학원 생활을 정리하고 돌아 볼 수 있는 시간을 가졌습니다. 졸업을 하려고 하니 대학원 생활이 짧게 느껴지는 것은 제가 많이 부족하고 배울 것이 더 많다는 아 쉬움 때문인 것 같습니다. 또한 대학원 생활을 마무리 하면서 돌이켜 봤을 때 많은 분들께 감 사하다는 말씀을 드리고 싶어 감사의 글을 쓰게 되었습니다.
우선 항상 저를 응원해주시고 믿어주신 저희 가족에게 감사합니다. 제가 기죽지 않게 항상 응 원해주신 아빠, 고민을 털어 놓으면 같이 걱정해주시고 잘 될 거라고 용기 주신 엄마, 제가 힘 들다고 할 때 마다 무심한 듯 챙겨준 경우에게 감사 드립니다. 저의 기둥처럼 지지해주시고 격려해주신 가족이 있었기 때문에 대학원 생활을 무사히 마칠 수 있었습니다. 정말 감사합니 다. 그리고 지도 교수님이신 김경택 교수님, 유자형 교수님 감사합니다. 많이 부족했던 저를 가르쳐 주시고 지도해 주셔서 무사히 졸업을 할 수 있게 된 것 같습니다. 앞으로도 더 나은 연 구자가 되도록 더욱 더 공부하고 노력 하겠습니다. 또한 심사위원이 되어주신 문회리 교수님, 홍성유 교수님, 박영석 교수님 감사합니다. 교수님들께서 해주신 질문과 조언으로 한번 더 제 연구에 대해 생각하고 정리 할 수 있었습니다. 또한 제가 서울에 있음에도 불구하고 생각해주 시고 챙겨주신 박치영 교수님, 김영삼 교수님께도 감사 드립니다. 그리고 우리 유기고분자 합 성 실험실 식구들께 감사 드립니다. 우리 실험실 사람들을 대학원 생활하며 만난 건 정말 큰 행운이라고 생각합니다. 우선 유니스트 때부터 동거동락 하던 우리 초창기 멤버 제 사수였던 현규 오빠, 제가 힘들 때 마다 묵묵히 도와준 윤주 오빠, 동갑이라고 정말 이것저것 많이 챙겨 준 비타민 같은 아라, 모든 자료의 완성도를 높여주고 그림에 소질 있는 나무 문곤, 제가 힘들 다고 하소연 할 때마다 힘내라고 응원해준 소령 언니, 짧은 시간 이였지만 잘 웃고 저를 좋아 해줬던 해나가 있었기 때문에 정말 즐거운 실험실 생활을 할 수 있었습니다. 또 우리 여 전사 들 (항상 옆에 있으면서 도와주고 격려 해준 마현지마 현지, 졸업의 고통을 함께 한 윤프로 미 선, 츤데래 처럼 도와주고 걱정해준 송정은선 정은, 달팽이와 고양이, 식물로 은밀하게 많은 대화를 한 이화백 채은, 영어로 힘들 때마다 도와준 희림)에게도 감사합니다. 만난 시간은 짧 지만 여전사들이 있어서 하루하루가 소중하고 행복했습니다. 부족한 언니 졸업한다고 도와주 고 응원해줘서 감사합니다. 그리고 우리 실험실 남학생들(슬우, 성민, 지원 오빠, 준영, 용범, 정민, 우림, 한슬, 준호, 종민)도 힘들 때 마다 옆에서 묵묵히 도와주고 응원해줘서 감사합니 다. 졸업 한 후에도 계속 다같이 만났으면 좋겠습니다. 그리고 대학원 생활에 있어서 현지 언 니를 만난 건 정말 큰 행운이라고 생각합니다. 현지 언니와 모든 일상을 공유하고 서로 의지 하며 대학원 생활을 할 수 있어서 기뻤고 감사합니다. 그리고 홍성유 교수님 실험실 대학원생 술친구 우겸이를 비롯해서 현호, 동선, 민호, 유자형 교수님 실험실 대학원생 Jeena, 서울 온 이후로 자주 보지 못했지만 같이 대학원 생활을 할 수 있어서 좋았습니다. 이 밖에도 많은 대