Development of Metal-Catalyzed Direct C-H Amination Reactions

  ============================================================ 제  목 :  Development of Metal-Catalyzed Direct C-H Amination Reactions 연  사 :  장석복 교수(KAIST) 일  시 :  2016년 12월 1일(목) 오후 4시 15분    장  소 :  화학관 첨단강의실(330118호) -----------------------------------------------------------  Development of Metal-Catalyzed Direct C-H Amination Reactions Sukbok Chang  Institute for Basic Science (IBS), Daejeon 305-701, Korea Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST), Daejeon 305-701, South Korea E-mail: sbchang@kaist.ac.kr   The mechanism of the Ir(III) and Rh(III)-mediated C–N coupling reaction, which is the key step of catalytic C-H amidation, was investigated in an integrated experimental and computational study. Novel amidating agents containing a 1,4,2-dioxazole moiety allowed for designing a stoichiometric version of the catalytic C–N coupling reaction and giving access to reaction intermediates that reveal details about each step of the reaction. Both DFT and kinetic studies strongly point to a mechanism where the M(III) complex engages the amidating agent via oxidative coupling to form a M(V)-imido intermediate, which then undergoes migratory insertion to afford the final C–N coupled product. For the first time, the stoichiometric versions of the Ir and Rh-mediated amidation reaction were compared systematically to each other. Iridium reacts much faster than rhodium (~ 1100 times at 6.7 oC) with the oxidative coupling being so fast that the activation of the initial Ir(III)-complex becomes rate-limiting. In the case of Rh, the Rh-imido formation step is rate-limiting. These qualitative difference stems from a unique bonding feature of the dioxazole moiety and the relativistic contraction of the Ir(V), which affords much more favorable energetics for the reaction. For the first time, a full molecular orbital analysis is presented to rationalize and explain the electronic features that govern this behavior. [1] S. H. Cho, J. Kim, J. Kwak, Sukbok Chang, Chem. Soc. Rev.2011, 40, 5068-5083 [2] K. Shin, H. Kim, S. Chang, Acc. Chem. Res. 2015, 48, 1040-1052 [3]Y. Park, K. T. Park, J. G. Kim, S. Chang, J. Am. Chem. Soc. 2015, 137, 4534-4542 [4] W. Xie, J. H. Yoon, S. Chang, J. Am. Chem. Soc. 2016, 138, 12605-12614 [5] Y. Park, J. Heo, M.-H. Baik, S. Chang, J. Am. Chem. Soc. 2016, 13      

• 2016-12-01
• 화학관 330118호

• POSTED DATE : 2016-11-28
• WRITER : 관리자
• HIT : 543

“Postsynthetic Modifications of Metal-Organic Frameworks“

========================================================== 제  목 :  Postsynthetic transmetalation of metal-organic frameworks 연  사 :  나명수 교수(UNIST) 일  시 :  2016년 11월 17일(목) 오후 4시 15분    장  소 :  화학관 첨단강의실(330118호) ===========================================================                               Postsynthetic transmetalation of metal-organic frameworks   Myoung Soo Lah   Department of Chemistry, Ulsan National Institute of Science & Technology (UNIST)   50 Unist-gil, Ulju-gun, Ulsan, Korea 44919 Fax: +82-(52)-217-2019 E-mail address: mslah@unist.ac.kr   The replacements of framework metal ions and ligands were investigated in metal–organic frameworks (MOFs). The transmetalated MOFs could be obtained by soaking an MOF in the solution of a new replacing metal ion. By simply controlling the soaking time, not only fully transmetalated isostructural framework structure but also selectively transmetalated core-shell bimetallic structure could be prepared. The ligand exchanged MOFs could also be obtained via soaking an MOF in the solution of a new replacing ligand. By controlling the concentration of the replacing ligand, not only an entropically favorable MOF with completely exchanged ligand but also enthalpically favorable MOF with selectively exchanged ligand in the alternating layers could be obtained. While there is no significant structural rearrangement of the framework during the replacement of the framework metal ion, the replacement of the framework ligand led to the significant structural reorganization of the framework.            

                            

   

• 2016-11-17
• 화학관 330118호

• POSTED DATE : 2016-11-17
• WRITER : 관리자
• HIT : 468

Living Supramolecular Polymerization

============================================================= 제  목 : Living Supramolecular Polymerization 연  사 : Dr Kazunori Sugiyasu(NIMS) 일  시 : 2016년 10월 6일(목) 오후 4시 30분 장  소 : 화학관 세미나실 (330226호실) ============================================================== Living Supramolecular Polymerization   Kazunori Sugiyasu Molecular Design & Function Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan E-mail: SUGIYASU.Kazunori@nims.go.jp      Supramolecular polymers are a new type of polymer in which monomeric units are brought together by reversible and highly directional non-covalent bonds, such as hydrogen bonding, coordination bonding, and p-p stacking. Therefore, supramolecular polymers are endowed with intriguing functionalities and properties that originate from the dynamic behavior of the non-covalent bonds. However, the “dynamic” reversible polymerization process in turn implies that controlling the length of supramolecular polymers is entropically unlikely. As such, in contrast to conventional polymer chemistry, an important challenge in realizing living polymerization technique has still remained in the supramolecular polymer chemistry1. In this presentation, I would like to show the first example of living supramolecular polymerization reported by us recently2. Our supramolecular polymerization was very unique in that the polymerization pathway was coupled with a competing aggregation pathway3. This pathway complexity dictated the spontaneous supramolecular polymerization to be kinetically controlled, and the addition of “seeds” of the supramolecular polymer initiated the supramolecular polymerization. We have investigated this polymerization process in a similar way to analyze the living polymerization: (1) the polymerization kinetics was the first order to the concentration of the seeds, (2) polymerization can be repeated many times, and (3) polydispersity indices (PDI) of the obtained polymers were around 1.1. All these results demonstrated that we succeeded for the first time in realizing living supramolecular polymerization.   Scheme 1. Pathway complexity of supramolecular polymerization2.     References (a) de Greef, T. F. A.; Smulders, M. M. J.; Wolffs, M. ; Schenning, A. P. H. J.; Sijbesma, R. P.; Meijer, E. W. Chem. Rev. 2009, 109, 5687; (b) van der Zwaag, D.; de Greef, T. F. A.; Meijer, E. W. Angew. Chem. Int. Ed. 2015, 54, 8334; (c) Ogi, S.; Stepanenko, V.; Sugiyasu, K.; Takeuchi, M.; Würthner, F. J. Am. Chem. Soc. 2015,137, 3300; (d) Kang, J.; Miyajima, D.; Mori, T.; Inoue, Y.; Aida, T. Science2015, 347, 646. Ogi, S.; Sugiyasu, K.; Manna, S.; Samitsu, S.; Takeuchi, M. Nat. Chem. 2014, 6, 188. Ogi, S.; Fukui, T.; Melinda, L. J.; Takeuchi, M.; Sugiyasu, K. Angew. Chem. Int. Ed. 2014, 53, 14363.

• 2016-10-06
• 화학관 330226호

• POSTED DATE : 2016-10-04
• WRITER : 관리자
• HIT : 471

[Plenary Seminar] 9월 29일(목)

====================================== 제  목 :  Control of molecular orientation, thermal stability, and photochemical stability in vapor-deposited organic glasses 연  사 :  Mark D. Ediger 교수(University of Wisconsin-Madison) 일  시 :  2016년 9월 29일(목) 오후 4시 15분    장  소 :  화학관 첨단강의실(330118호) --------------------------------------                                                         

Control of molecular orientation, thermal stability, and photochemical stability in vapor-deposited organic glasses Mark Ediger University of Wisconsin-Madison   We have used physical vapor deposition and the mobility of glassy surfaces to prepare what are likely the most stable glasses on the planet.(1) These materials have the properties expected for “million-year-old” glasses, including high density and high mechanical moduli.(2) Surprisingly, these glasses “melt” like crystals, with a constant velocity transformation front.(3) In addition, they resist photochemical degradation better than liquid-cooled glasses. Molecular orientation in vapordeposited glasses can be highly anisotropic.(4) These properties all depend systematically on the substrate temperature during deposition and can be measured efficiently with high throughput spectroscopic ellipsometry.(5)   The interesting properties of vapor-deposited glasses arise from the high mobility of glass surfaces. During deposition, molecules near the free surface have the opportunity to sample many different packing arrangements. This mechanism allows the molecular orientation in vapor-deposited glasses to be predicted from molecular dynamics computer simulations(4, 6) and could be useful for optimizing the performance of organic light emitting diodes (OLEDs). 1. Swallen SF, et al. (2007) Organic glasses with exceptional thermodynamic and kinetic stability. Science 315(5810):353-356. 2. Kearns KL, Still T, Fytas G, & Ediger MD (2010) High-Modulus Organic Glasses Prepared by Physical Vapor Deposition. Adv. Mater. 22(1):39-+. 3. Swallen SF, Traynor K, McMahon RJ, Ediger MD, & Mates TE (2009) Stable Glass Transformation to Supercooled Liquid via Surface-Initiated Growth Front. Phys. Rev. Lett. 102(6):065503. 4. Dalal SS, Walters DM, Lyubimov I, de Pablo JJ, & Ediger MD (2015) Tunable molecular orientation and elevated thermal stability of vapor-deposited organic semiconductors. P Natl Acad Sci USA 112(14):4227-4232. 5. Dalal SS, Fakhraai Z, & Ediger MD (2013) High-Throughput Ellipsometric Characterization of Vapor-Deposited Indomethacin Glasses. J. Phys. Chem. B 117(49):15415-15425. 6. Singh S, Ediger MD, & de Pablo JJ (2013) Ultrastable glasses from in silico vapour deposition. Nature Materials 12(2):139-144.

                      

• 2016-09-29
• 330118호실

• POSTED DATE : 2016-09-29
• WRITER : 관리자
• HIT : 470

Efficient Synthetic Methods of N-Heterocyclic Compounds using Pyridinium Zwitterion

===================================================================================== 제  목 : Efficient Synthetic Methods of N-Heterocyclic Compounds using Pyridinium Zwitterion 연  사 : 유은정 교수(강원대학교) 일  시 : 2016년 6월 9일(목) 오후 4시 30분 장  소 : 화학관 세미나실 (330118호실) ===================================================================================== Efficient Synthetic Methods of N-Heterocyclic Compounds using Pyridinium Zwitterion Eun Jeong Yoo Department of Chemistry, Kangwon National University, Chuncheon 200-701, Korea E-mail:ejyoo@kangwon.ac.kr [m+n]-Dipolar cycloaddition is a powerful and widely used strategy for synthesizing heterocyclic compounds in a single operation without giving rise to byproducts. Among the known dipoles, azomethine ylide, consisting of an iminium ion adjacent to a carbanion, is an allyl anionic type 1,3-dipole that can be applied to construct N-heterocyclic compounds. However, most studies have mainly focused on [3+2]-dipolar cycloaddition using well-known 1,3-dipoles and 2p-dipolarophiles, while scarce attention has been focused on the development of new types of dipoles, such as 1,2-dipole, 1,4-dipole, and 1,5-dipole, for the formation of non-five-memberted heterocycles. In this presentation, [5+n]-dipolar cycloaddition, which is an extraordinary tool for formation of medium-sized N-heterocyclic compound, will be present. Air-stable pyridinium zwitterion is efficiently prepared via the rhodium-catalyzed reaction between pyridines and 1-sulfonyl-1,2,3-triazoles. This unprecedented pyridinium zwitterion are quite stable and exhibits different pattern of charge distribution in comparison with that of typical azomethine ylides. In addition, isolated zwitterions could be used as a 1,5-dipole for forming medium-sized heterocyclic compounds. Thermal [5+2]-dipolar cycloaddition of pyridinium zwitterions and dimethyl acetylenedicarboxylate (DMAD) successfully occurs to afford the seven-membered heterocycles with excellent yields. This breakthrough spurred the development of rhodium(II)-catalyzed three-component [5+2] cycloaddition reactions of pyridines, 1-sulfonyl-1,2,3-triazoles, and activated alkynes via the in situ generated 1,5-dipole; thus, a user-friendly and operationally simple strategy for systematic generation of the core structure of 1,4-diazepines was afforded. We will also discuss a new type of intermolecular rhodium(II)-catalyzed [5+3]-dipolar cycloaddition of pyridinum zwitterions and enol diazoacetates. This higher-order cycloaddition allows for the formation of an eight-membered heterocyclic skeleton, which is otherwise difficult to construct. The optimized dipolar cycloaddition occurs efficiently under mild conditions over a wide range of pyridinium zwitterions with high functional group tolerance. References Lee, D. J.; Ko, D.; Yoo, E. J.* “A Class of Rh(II)-Catalyzed Cycloaddition Reaction of Non-classical 1,5-Dipoles for Formation of Eight-Membered Heterocycles” Angew. Chem., Int. Ed. 2015, 54, 13715. Yoo, E. J.* “Azomethine Ylide: an Isolable 1,5-Dipole for Affecting [5+2] Cycloaddition Reaction” Synlett 2015, 26, 2189 (SYNPACTS, invited article). Lee, D. J.; Han, H. S.; Shin, J.; Yoo, E. J.* “Multicomponent [5+2] Cycloaddition Reaction for the Synthesis of 1,4-Diazepines: Isolation and Reactivity of Azomethine Ylides” J. Am. Chem. Soc. 2014, 136, 11606

• 2016-06-09
• 화학관 330118호

• POSTED DATE : 2016-06-03
• WRITER : 관리자
• HIT : 722

Microgels: Can we control their internal structure?

============================================================== 제  목 : Microgels: Can we control their internal structure? 연  사 : Prof.Imre Varga(Loránd Eötvös University, Budapest) 일  시 : 2016년 4월 19일(화) 오후 4시 30분 장  소 : 화학관 세미나실 (330118호실) ============================================================== Microgels: Can we control their internal structure? Imre Varga   Coordinator of the Marie Curie Initial Training Network NanoS3. Institute of Chemistry, Eötvös Loránd University, 1117 Budapest Pazmany s. 1/A, Hungary .   email: imo@chem.elte.hu   The synthesis and characterization of poly(N-isopropylacrylamide) - based multi-responsive microgel particles has attracted a significant interest in the last decade. They are considered as promising candidates in many applications ranging from heavy metal scavengers to diagnostic applications, and controlled drug delivery systems. However, the simple uniform structure of these particles presents a serious limitation in many respects e.g. resulting in limited colloid stability and loading and release characteristics. To meet the challenges of nanotechnology, there is compelling need to develop synthetic methods for controlling the internal structure of the nanogel beads.   I will provide a summary of our work related to the preparation, characterization and application of pNIPAm based microgel particles. I will present a novel approach for the synthesis of microgel beads with controlled internal structure. The method allows to control the radial distribution of co-monomers within the gel particles, thus facilitating the preparation of microgel beads e.g. with homogenous crosslink density distribution or with unique hydrophilic shells. The formed core/shell structures can be further utilized to create either hierarchical nanoparticles or 3D-structures. I will show a few examples for the formation of hierarchical structures based on either electrostatic or host/guest interactions.    

• 2016-04-19
• 화학관 330118호

• POSTED DATE : 2016-04-15
• WRITER : 관리자
• HIT : 771

4/15(Fri.) KANEKA International Symposium 2016 안내

4/15(Fri.) KANEKA International Symposium 2016 안내     저희 성균관대학교에서는 2010년 KANEKA(주)로부터 지원을 받아 KANEKA/SKKU Incubation Center를 설립하여 전자재료 관련 기술과제에 관한 공동연구를 진행해왔습니다.     센터 행사의 일환으로 올해도 오는 4월 15일(금) 오전 9시 30분부터 성균관대에서 제 6회 “KANEKA/SKKU Incubation Center International Symposium 2016”을 개최할 예정입니다. 첨부자료에서 보실 수 있는 바와 같이, 연사는 지금까지와 마찬가지로 각 분야에서 세계적인 활약을 하고 계시는 저명한 교수 및 연구자들입니다. 특히, 기조강연을 맡은 Wisconsin대학 유혁(Yu Hyuk)교수는 재미교포로 세계적인 업적을 세운 훌륭한 교수입니다.     특별히 사전 접수가 필요 없으며, 등록비도 없으므로 당일 행사장에 부담 없이 와 주시면 감사하겠습니다.   강연에 관한 자세한 사항은 첨부파일의 포스터 및 초록집을 참고하여 주십시오.     행사명 : KANEKA/SKKU Incubation Center International Symposium 2016 날짜 : 2016년 4월 15일 (금) 장소 : 자연과학캠퍼스 학술정보관 Auditorium(B1) 시간 : 오전 9시 30분 ~ 오후 5시   강연자 및 타이틀 Hyuk Yu (University of Wisconsin-Madison) “Evolutionary Directions of US Chemical Research”   Tomiki Ikeda (Chuo Univ.) “Photomobile Polymer Materials: Structures and Functions”   Changhoo Chun (Seoul National Univ.) “Artificial Lighting for Plant Production in Vertical Farming”   Junji Kido (Yamagata Univ.) “White OLEDs for Displays and General Lighting”   Yasuo Nakane (Mizuho Securities Ltd.) “Outlook on Flat Panel Display Industry, LCD or OLED?”   Taeghwan Hyeon (Seoul National Univ.) “Designed Chemical Synthesis and Assembly of Uniform-sized Nanoparticles for Medical   and Energy Applications”   Gi-Ra Yi (Sungkyunkwan Univ.) “High-Density DNA Brushes on Polymer Particles for Building Up Colloidal Superstructures”   Tsuyoshi Sekitani (Osaka Univ.)                 “Imperceptible Sheet-Type Sensors for Cyber–Physical Systems”      

• 2016-04-15
• 자연과학캠퍼스 학술정보관 Auditorium(B1)

• POSTED DATE : 2016-03-31
• WRITER : 관리자
• HIT : 867

“In vivo NMR to elucidate Brain Function“

2016 Spring/Summer Semester Plenary Seminar at SKKU Department of Chemistry   ====================================== 제  목 :  In vivo NMR to elucidate Brain Function 연  사 :  김성기 교수(Center for Neuroscience Imaging Research Institute for Basic Science, SKKU) 일  시 :  2016년 6월 2일(목) 오후 4시 15분    장  소 :  화학관 첨단강의실(330118호) --------------------------------------                                              In vivo NMR to elucidate Brain Function Seong-Gi Kim(seonggikim@skku.edu) Center for Neuroscience Imaging Research Institute for Basic Science Sungkyunkwan University  NMR has been extensively used in chemistry for determining molecular structures and dynamics.  When NMR is used as an imaging mode with gradient coils, it is referred to as magnetic resonance imaging, which is used for non-invasive diagnostics of diseases. In my research, MRI is used for determining brain function non-invasively by utilizing a change of paramagnetic deoxyhemoglobin.  In my talk, I will discuss basic idea of functional MRI, current research lines, and IBS center’s NMR facility.                                                                                            

• 2016-06-02
• 화학관 330118호

• POSTED DATE : 2016-06-03
• WRITER : 관리자
• HIT : 791

“Principles and Applications of Coherent Multidimensional Spectroscopy

 2016 Spring/Summer Semester Plenary Seminar at SKKU Department of Chemistry   ====================================== 제  목 :  Principles and Applications of Coherent Multidimensional Spectroscopy 연  사 :  조민행 교수(고려대학교) 일  시 :  2016년 5월 26일(목) 오후 4시 15분    장  소 :  화학관 첨단강의실(330118호) --------------------------------------                                                         

Principles and Applications of Coherent Multidimensional Spectroscopy

 

Minhaeng Cho

Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Korea University, Seoul 02841, Korea. Department of Chemistry, Korea University, Seoul 02841, Korea.   Multi-dimensional optical or vibrational spectroscopy is a special class of time domain nonlinear optical spectroscopy that employs multiple ultra-fast laser pulses to obtain information about the couplings between quantum states in a variety of molecular or condensed matter systems. Since these couplings are often sensitive to the detailed structural configuration of the active molecules and the overall dynamical system evolution including interactions with the local environment, a great deal of information can potentially be obtained. It is especially well suited to follow the evolution of quantum coherences in light initiated reactions, including photosynthesis, or as an exceptionally useful probe of protein dynamics in solution. In fact, as demonstrated over the years, a vast number of different experimental configurations are possible depending on the chosen pulse sequences, geometric arrangement and polarization and signal detection method. Hopefully, this talk imparts a sound conceptual basis that will enable the diligent researchers to understand the importance of this extensive and rapidly growing research field.      

• 2016-05-26
• 화학관 330118호

• POSTED DATE : 2016-05-18
• WRITER : 관리자
• HIT : 596

“Translational Research in the Development of Polymerization Catalysts“

2016 Spring/Summer Semester Plenary Seminar at SKKU Department of Chemistry    이분열 교수, 아주대학교 “Translational Research in the Development of Polymerization Catalysts“화학적 지식의 경제성 창출? 가능한가? 화학이 돈이다!    Place: Chemistry Bld. Rm 330118Time: 4:15~5:30 pm. =========================================================================================== Translational Research in the Development of Polymerization Catalysts (중합 촉매 개발을 통한 대학 개발 기술의 산업체 기술이전) Bun Yeoul Lee Department of Molecular Science and Technology, Ajou University, Suwon 443-749 Korea bunyeoul@ajou.ac.kr   1) Olefin polymerizations In our laboratory, more than 100 new titanium and zirconium complexes have been preapred for olefin polymerizations for the last two decades. Especailly, organolithium compounds have been actively utilized in the construction of those complexes. The representative complexes1 and 2 can be prepared in two steps in Kg-scale, which exhibit high activity, high 1-octene incorporation, and high molecular weight in the ethylene/1-octene copolymerizations. Complex 1 is currently used in industry (LG) for the production of polyolefin elastomers (~80,000 T/y) and eventually complex 2was licensed out to Lotte Chem in 2011 with affront fee 600,000,000 Won.   2) CO2/epoxide copolymerization A highly active catalyst (3) was discovered for the CO2/epoxide copolymerization. Complex 3 showed a high TON up to ~20000 and a high turnover frequency (TOF) of ~20000 h-1 that produced a strictly alternating copolymer with a high molecular weight (Mn) of up to 300000. The catalyst was licensed out to SK in 2008 with affront fee 600,000,000 Won. 3) New compostable polymers from CO2 High-molecular-weight poly(1,4-butylene carbonate-co-terephthalate)s were prepared by condensation copolymerizations of 1,4-butanediol, dimethyl carbonate, and dimethyl terephthalate, which shows the comparable thermal properties to the commercialized compostable polyesters such as PLA, PHA, PBAT, and PBSA. The polymers were licensed out to Lotte Chem in 2014 with affront fee 500,000,000 Won.          

• 2016-04-14
• 화학관 330118호

• POSTED DATE : 2016-04-12
• WRITER : 관리자
• HIT : 524