===================================================================================== 제 목 : Investigation of Innovative Synthetic Approach for Successful Implementation of Fragment-Based Design 연 사 : 홍승우 교수님(KAIST) 일 시 : 2017년 6월 7일(수) 오전 11시 장 소 : 화학관 1층 첨단강의실 (330118호실) ===================================================================================== Investigation of Innovative Synthetic Approach for Successful Implementation of Fragment-Based Design Sungwoo Hong Center for Catalytic Hydrocarbon Functionalizations & Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, Korea e-mail: email@example.com Solutions to problems that are posed by organic, medicinal, biological and material science, demand synthetic innovation with efficient synthetic routes. Our current research is focused on studying breakthrough knowledge in catalytic synthetic methods and molecular design that have high impact on broader scientific fields. The state-of-the-art of approach can be seen using systematic experimental and theoretical methods from three steps: (1) development of innovative synthetic methods that allow rapid access to molecular complexity and structural diversity of privileged fragments, (2) fragment-based drug design (FBDD) and de novo design methods connecting privileged building blocks, (3) development of potent and selective inhibitors based on understanding the mechanisms at the molecular level. The selective C–H bond functionalization has become the favored reaction methods in practical synthetic processes. The new catalytic synthetic methods allow us to perform the unprecedented disconnection of target molecules, affording innovative and imaginative synthetic strategies of so-called “privileged scaffolds”. The power and efficiency of direct C–H functionalization could be further enhanced by combining such catalytic transformations into a one-pot process, which is highly desirable by providing a powerful platform for constructing complicated key motifs from simple starting materials. Subsequent medicinal chemistry studies involving a modular approach and privileged fragments assembly, will provide bases for the development of pharmaceutical agents via structure-based design. The new catalytic synthetic methods will function as competent tools directly utilized in cross coupling reactions capable of connecting privileged building blocks, providing opportunities for the successful implementation of fragment-based drug design (FBDD) and eventually streamline drug discovery research.
============================================================== 제 목 : Evolution of Form in Metal-Organic Frameworks 연 사 : 최원영 교수님(UNIST) 일 시 : 2017년 6월 1일(목) 오후 4시 30분 장 소 : 화학관 2층 서병인 강의실 (330226호실) ============================================================== Evolution of Form in Metal-Organic Frameworks Wonyoung Choe Department of Chemistry Ulsan National Institute of Science and Technology Ulsan, 44919 Self-assembly has proven to be a widely successful synthetic strategy for functional materials, especially for Metal-Organic Materials (MOMs), an emerging class of porous materials consisting of Metal-Organic Frameworks (MOFs) and Metal-Organic Polyhedra (MOPs). However, there are areas in MOM synthesis in which such self-assembly has not been fully utilized, such as controlling the interior of MOM crystals. Here, we demonstrate sequential self-assembly strategy for synthesizing various forms of MOM crystals, including double-shell hollow MOMs, based on single-crystal to single-crystal transformation from MOP to MOF. Moreover, this synthetic strategy also yields other forms, such as solid, core-shell, double and triple matryoshka, and single-shell hollow MOMs, thereby exhibiting form evolution in MOMs. We anticipate that this synthetic approach might open up a new direction for the development of diverse forms in MOMs, with highly advanced areas such as sequential drug delivery/release and heterogeneous cascade catalysis targeted in the foreseeable future.
====================================== 제 목 : Multiselective Diels–Alder Reaction Induced by Chiral Supramolecular Lewis Acid Catalysts 연 사 : Prof. Kazuaki Ishihara(Nagoya University) 일 시 : 2017년 5월 18일(목) 오후 4시 15분 장 소 : 화학관 1층 첨단강의실(330110호) -------------------------------------- Multiselective Diels–Alder Reaction Induced by Chiral Supramolecular Lewis Acid Catalysts Kazuaki Ishihara Nagoya University, Japan The control of multiple selectivities is still a challenging subject in modern organic chemistry. In this regard, the Diels–Alder (DA) reaction is a significant tool for the total synthesis of complex organic molecules. When used in the DA reaction, conventional chiral catalysts can discriminate the prochiral enantio-face (i.e., re/si-face) of a dienophile regardless of the diene (two-dimensional discrimination). However, they cannot control the diastereo- (i.e., endo/exo-), regio-, site-, or substrate-selectivity, since this would require the three-dimensional discrimination of isomeric transition-state structures. In general, huge enzymes in vivo can realize such multi-selectivity by using a chiral cavity, which provides a three-dimensional space that includes an active site. The cavities of enzymes are conformationally flexible to catch substrates and release products (induced fit function). To overcome the limited selectivity due to the small cavity and conformational rigidity of conventional chiral Lewis acid catalysts, supramolecular catalysts, which are prepared in situfrom small components by coordinating bonds, have been considered. Indeed, there are a few examples of the use of supramolecular O-shaped catalysts that induce anomalous site-selectivity in DA reactions. However, their catalytic activities are not adequate due to their conformational rigidity. In contrast, Prof. Ishihara et al.envisioned that chiral supramolecular U-shaped catalysts, which are more conformationally flexible than O-shaped catalysts, could induce high catalytic activity with multi-selectivity. In this lecture, Prof. Ishihara presents that an asymmetric DA reaction of propargyl aldehyde with cyclopentadiene can be controlled so as to provide high enantio-, endo/exo-, regio-, and substrate-selectivities by using chiral supramolecular U-shaped catalysts.
====================================== 제 목 : 현대화학에서 계산양자화학의 역할: 어제와 오늘 연 사 : 이윤섭 교수님(한국과학기술원 화학과) 일 시 : 2017년 4월 27일(목) 오후 4시 15분 장 소 : 화학관 1층 첨단강의실(330110호) -------------------------------------- 현대화학에서 계산양자화학의 역할: 어제와 오늘 이윤섭 한국과학기술원 화학과 계산양자화학의 역사는 전산기의 발달과 궤를 같이하여 최근에 눈부시게 발전하고 있고 당분간은 급속한 확대추이가 지속되리라 예상된다. 그간 계산양자화학의 방법론 발달에서 중요한 사항과 그에 따른 응용예의 확산을 살펴보고자 하는데, 객관적 중요성을 충분히 반영한 역사나 개요보다는 연사의 경험과 관련된 주제의 간단한 설명으로 양자화학에서 상대론 효과를 취급하는 방법과 상대론 효과에 영향을 받은 분자 구조와 특성의 의미 있는 변화를 주로 소개한다. 현대화학이란 어휘는 학문의 특정분야로 인식이 이루어지고 있지는 않으나 현대물리학이 양자역학과 상대성원리를 근간으로 하고 있음을 생각하면, 상대론적 양자화학을 현대화학의 주요주제로 간주할 수 있겠다. 상대론 효과가 현재 수행되는 다수의 양자화학 계산에 일부나마 포함되어 있음을 고려할 때 전자구조에서 나타나는 상대론 효과의 정성적 이해는 미래를 위한 방법론 개발과 현명한 양자화학 계산 응용에 필요하다. 일례로 동전용 금속들에서 금이 은보다 동에 가깝게 보임은 주요원인이 에너지 준위에 영향을 주는 상대론적 효과 때문이다.
============================================================== 제 목 : Physical-Organic Approaches to Studying Protein Chemistry 연 사 : Prof. Kyungtae Kang(Department of Applied Chemistry, Kyung Hee University) 일 시 : 2017년 4월 13일(목) 오후 4시 30분 장 소 : 화학관 2층 서병인 강의실 (330226호실) ============================================================== Physical-Organic Approaches to Studying Protein Chemistry Kyungtae Kang Department of Applied Chemistry, Kyung Hee University, 1732 Dyeogyoung-daero, Giheung-gu, Youngin, Gyeonggi 17104, Republic of Korea Biomolecular recognition is governed as much by rearrangements of the water that hydrates the interacting molecules as it is governed by their direct interactions. A detailed understanding of the mechanisms by which these rearrangements contribute to the thermodynamics of recognition processes is, thus, essential for better understanding—and predicting—the energetics of important biomolecular recognitions. In this respect, the hydrophobic effect—the tendency of nonpolar surfaces to associate in aqueous solution—is one of the major driving forces of many biomolecular recognition events. The hydrophobic effect arises from free energetically favorable rearrangements of water, whose thermodynamic consequences are fairly well understood for flat, nonpolar entities in aqueous solution (where the intermolecular association of such entities gives rise to the entropically favorable, enthalpically unfavorable release of ordered waters from their surfaces), but incompletely understood—and difficult to predict—for interactions between ligands and the morphologically complex and chemically heterogeneous binding pockets of proteins. In this talk, I will introduce our efforts to examine the role of water filling the binding pocket of human carbonic anhydrase II (HCAII, EC 4.2.11) in its bindings with structurally varied sulfonamide ligands, by combining isothermal titration calorimetry, X-ray crystallography, site-directed mutagenesis, and molecular dynamics simulations. By this set of methods, we showed that (i) the hydrophobic surface area of a ligand does not improve DGºb, unless that increased non-polar area is buried in the binding process, and values of DHºb and -TDSºb depend on the structure (or morphology) of a ligand; (ii) reorganizing networks of water inside the binding pocket by mutating amino acids thereof brings about huge and compensating changes in values of DHºband -TDSºb. References 1. D. Chandler, Nature437, 640 (2005). 2. P. W. Snyder, M. R. Lockett, D. T. Moustakas, G. M. Whitesides, Eur. Phys. J.-Spec. Top. 223, 853 (2013).
===================================================================================== 제 목 : Chiral Tetrahydrothiophene Ligands in Asymmetric Catalysis 연 사 : Prof. Rong-Jie Chein(Institute of Chemistry, Academia Sinica) 일 시 : 2017년 4월 4일(화) 오후 4시 30분 장 소 : 화학관 1층 강의실 (330118호실) ===================================================================================== Chiral Tetrahydrothiophene Ligands in AsymmetricCatalysisRong-Jie CheinInstitute of Chemistry, Academia Sinica, Nankang, Taipei 11529, TaiwanE-mail: firstname.lastname@example.org Chiral sulfur ligands are becoming a versatile tool in organic chemistry due to theblossomed development achieved in the past years. This presentation describes anexpeditious and efficient preparation of enantiopure (thiolan-2-yl)diarylmethanols andthe applications of their derivatives to catalytic and asymmetric Corey-Chaykovskyepoxidation,1 the imino Corey-Chaykovsky aziridination,2,3 as well as the firstoxathiaborenium catalyzed asymmetric Diels-Alder reaction.4,5 Figure 1. Synthesis and applications of chiral THT ligands Reference1. Wu, H.-Y.; Chang, C.-W.; Chein, R.-J. J. Org. Chem. 2013, 78, 5788-5793.2. Huang, M.-T.; H.-Y. Wu; Chein, R.-J. Chem. Commun. 2014, 50, 1101-1103.3. Wang, S.-H.; Chein, R.-J. Tetrahedron, 2016, 72, 2607-2615..4. Kumar, S. N.; Yu, I. F.; Chein, R.-J. Org. Lett. 2017, 19, 22-25. (Highlighted byC&EN 2017, 95(1), 9).5. Tsai, M.-L.; Chein, R.-J. to be submitted.Rong-Jie Chein (陳榮傑), National Chiao Tung University (Ph.D., 2005), HarvardUniversity (Postdoctoral Fellow, E. J. Corey Lab, Jan. 2007 - June 2009). AssistantResearch Fellow of Academia Sinica (July 2009 - May 2015). Associate ResearchFellow (May 2015 - ). Research fields: (1) Development of new synthetic strategiesand methods. (2) Total synthesis and the study of the chemistry and biology of naturalproducts and designed molecules.
============================================================== 제 목 : Soft Matter at Rubbing Interfaces: Lessons from Nature to Design Water-friendly Tribosystems 연 사 : 이승환 교수님(Technical University of Denmark) 일 시 : 2017년 3월 30일(목) 오후 4시 30분 장 소 : 화학관 2층 서병인강의실 (330226호실) ============================================================== Soft Matter at Rubbing Interfaces: Lessons from Nature to Design Water-friendly Tribosystems Seunghwan Lee Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark Life-long maintenance of biotribosystems, such as synovial joints, ocular tracts, and oral cavity, is remarkable and even puzzling considering that the base stock for the lubrication is water. For most man-made engineering systems, water is generally excluded as lubricant due to its poor capabilities to withstand external loads on its own. Nature solves this problem by incorporating pressure-responsive, “smart coatings”, such as mucus gel layers on the surface, and thus facilitate the entrainment and retainment of water (lubricant) at the rubbing interfaces. Mucins, a family of high-molecular-weight glycoproteins and a main macromolecular constituent of mucus gels, are interesting also because they show unique slipperiness at the interface composed of synthetic materials too. This, in turn, has inspired the development of mucin-like, brush-forming synthetic polymers, which can be applied in the lubrication of engineering materials with water. Biophysical properties of both mucinous glycoproteins and their mimics, brush-forming polymers, are very sensitive to environmental changes, and this feature can be exploited to optimize their properties for particular applications. Studies on soft matter at the rubbing interfaces firstly help understand the biological mechanisms of lubrication and provide useful hints for biomimetic lubrication engineering. Furthermore, various fundamental properties of soft matter on surface can be revealed only by being exposed to interfacial shear stresses. This talk will provide an overview on recent researches on the conformation, surface adsorption, and biotriobological properties of mucins/mucus gels with varying origin, purity, and environment as well as synthetic brush-like polymer chains, including poly(ethylene oxide)(PEO)-based copolymers, carbohydrate-based copolymers, and polyeletrolyte-based copolymers.
================================================== 제 목 : Quantum simulation of molecular problems 연 사 : 허준석 교수님(성균관대학교 화학과) 일 시 : 2017년 3월 9일(목) 오후 4시 30분 장 소 : 화학관 세미나실 (330226호실) ================================================== Quantum simulation of molecular problems Joonsuk Huh Department of Chemistry, Sungkyunkwan University The intrinsic nature of parallelism of quantum states is anticipated to give extraordinary computational power to quantum processors for certain problems. A linear optical network is one of the simplest quantum processors that it could reveal the (computational) quantum supremacy against classical machines. A photon-sampling problem in a linear optical network, so-called Boson Sampling, is a specially designed mathematical problem, which is expected to be intractable for any classical machine. In my talk, I will present what we can do with the photonic quantum simulator (non-universal quantum computer) practically. Boson Sampling is generalized with Gaussian input states to simulate the molecular vibronic spectroscopy [1-5].  J. Huh, G. G. Guerreschi, B. Peropadre, J. R. McClean, and A. Aspuru-Guzik. Boson Sampling for Molecular Vibronic Spectra. Nature Photon. 9 (2015): pp 615-620.  J. Huh and M.-H, Yung, Hierarchy in Sampling Gaussian-correlated Bosons, Preprint: arXiv:1608.03731.  Y. Shen, J. Huh, Y. Lu, J. Zhang, K. Zhang, S. Zhang and K. Kim, Quantum simulation of molecular spectroscopy in trapped-ion device, Preprint: arXiv:1702.04859  D. G Olivares, B. Peropadre, J. Huh and J. J. García-Ripoll, Quantum emulation of molecular force fields: A blueprint for a superconducting architecture Preprint: arXiv:1611.08101  B. Peropadre, J. Huh and C. Sabin, Dynamical Casimir effect for boson sampling, Preprint: arXiv:1610.07777
============================================================== <세미나1> 제 목 : Visible Light-Induced Radical Transformations 연 사 : 조은진 교수님(중앙대학교) 일 시 : 2016년 12월 8일(목) 오후 4시 장 소 : 화학관 2층 세미나실(330226호실) ============================================================== Visible Light-Induced Radical Transformations Eun Jin Cho Department of Chemistry, Chung-AngUniversity, Seoul 06794, Republic of Korea E-mail:email@example.com Recently, visible light photocatalysis has attracted substantial attention due to its environmental compatibility and mechanistic versatility in promoting a large number of synthetically important reactions. We have developed a variety of radical transformations using Ru-, Ir-, and Pt-based photocatalysts under visible light irradiation. Fluoroalkylated organic compounds play significant roles in the pharmaceutical, agrochemical, and material sciences owing to the substantial influence that fluorine substitution has on the physical and chemical properties of substances. Visible light-induced methods allowed access to fluoroalkyl group-containing molecules, such as –CF2R, –CF3,and –CF2SPh groups.1 In the studies, electron deficient carbon-centered fluoroalkyl radicals were successfully generated by the appropriate choice of fluoroalkyl source, photocatalyst, additives, and solvent. Notably, we have observed that additives significantly affect the efficiencies and selectivities of these reactions and can even change the outcome of the reaction by playing additional roles during its course. By understanding the roles of additives, we developed several controlled fluoroalkylation reactions of alkenes and alkynes where different products were formed selectively from the same starting substrates.2-4 Polyheteroaromatic compounds have also attracted much attention due to their unique p-conjugation, which make them suitable functional materials in many applications. The synthesis of carbazole motif has been accomplished using N-substituted amidobiaryls through the merger of photoredox and palladium catalysis.5 The use of 1 mol% of an Ir-photocatalyst obviated the typical high loadings of external chemical additives in the transformation. And recently, we synthesized a new class of polyheteroaromatics from the coupling process between readily accessible 2-heteroaryl substituted aromatic amines and heteroaromatic alkynes by an Ir-catalyzed visible light photocatalysis.6 [References] Chatterjee, T.; Iqbal, N.; You, Y.; Cho, E. J.Acc. Chem. Res. 2016, 49, 2284-2294. Iqbal, N.; Jung, J.; Park, S.; Cho, E. J. Angew. Chem. Int. Ed. 2014, 53, 539-542. Yu, C.; Iqbal, N.; Park, S.; Cho, E. J. Chem. Commun. 2014, 50, 12884-12887. Choi, Y.; Yu, C.; Kim, J. S.; Cho, E. J. Org. Lett. 2016, 18, 3246-3249. Choi, S.; Chatterjee, T.; Choi, W. J.; You, Y.; Cho, E. J. ACS Catalysis, 2015, 5, 4796-4802. Chatterjee, T.; Choi, M. G.; Kim, J.; Chang, S.-K.; Cho, E. J. Chem. Commun. 2016, 52, 4203-4206. ============================================================== <세미나2> 제 목 : Iron Catalysis:from High-valent Lewis Acid Catalyst to Low-valent Redox Catalyst 연 사 : 강은주 교수님(경희대학교) 일 시 : 2016년 12월 8일(목) 오후 5시 장 소 : 화학관 2층 세미나실(330226호실) ============================================================== Iron Catalysis: from High-valent Lewis Acid Catalyst to Low-valent Redox Catalyst Eun Joo Kang e-mail: firstname.lastname@example.org The use of iron compounds as catalysts in organic synthesis is attractive for a number of reasons. It is the most abundant metal in the earth’s crust after aluminum and therefore is much cheaper than the precious metals that are often applied. Regarding the catalytic efficiency and broad applicability, at present iron is still behind palladium as the most versatile catalytic metal, however, the tremendously increasing number of publications demonstrates that iron is catching up. Unlikely palladium, iron can adopt ocidation states from -2 to +5, thus, in low oxidation states it may be operative as an iron-centered nucleophile and catalyze nucleophilic substitutions and additions. In contrast, iron Lewis acid catalyzed reactions have been known for a long time, for example electrophilic aromatic substitutions. Haaving this potential in mind, our lab has been interested in alternative use of iron catalysis in the following organic synthesis. First, we reported Fe catalyzed atom-economical tandem reaction of alkene-iodide in the present of equimolar aryl Grignard reagent. Aryl Grignard reagent is used to generate Fe-Grignard complex and the counter aryl anion is used in the further cross-coupling, thereby affording the tandem cyclization/cross-coupling radical reaction. Also, the nucleophilic cyclization reactions of allenes were catalyzed by Fe(III) to afford the corresponding heterocycle compound. Fe(III) catalysts were applied in the reactions of allenyl amides or allenyl alcohols and cyclized compounds containing O or N heteroatom were produced with moderate to good yields.
============================================================== 제 목 : 화학작용제 지속도 연구 연 사 : 임종선 부이사관(국군화학방어연구소) 일 시 : 2016년 11월 24일(목) 오후 3시 장 소 : 화학관 2층 세미나실 (330226호실) ============================================================== 화학작용제 지속도 연구 소형풍동장치를 이용하여 화학작용제의 증발 및 소멸특성의 연구를 통해 야전환경 조건 하 화학작용제의 지속도와 관련 데이터를 축적하고자 본 연구를 수행하였다. 실험에 사용한 화학작용제는 HD와 GD이며, 지표물질로는 비다공성 표면으로 유리, 다공성 표면으로 콘크리트 및 나지표면을 이용하여 실험을 진행하였다. 실험에 적용한 환경조건은 온도, 풍속, 오염량의 세가지 변수이며, 온도는 17℃ ~ 45℃, 풍속은 0.8km/h ~ 13km/h, 오염량은 1g/㎡ ~ 10g/㎡의 범위에서 실시하였다. 실험을 통해 획득한 데이터는 美 ECBC의 실험데이터와 비교하기 위해 ECBC에서 데이터를 처리한 방식대로 데이터를 처리해 비교를 실시하였다. 획득한 ECBC 데이터는 HD와 VX 데이터이다. 미국의 데이터와 비교하기 위해 작용제별 증발속도를 산출해 ECBC에서 제시한 증발속도 계산식을 이용하여 계산된 증발속도 값 및 실제 실험을 통해서 획득된 미국의 증발속도 데이터와 비교하였다. 또한, HD의 STEL(short-term exposure limit), VX의 IDLH(immediately dangerous to life or health) 농도에 해당하는 농도인 0.003mg/㎥에 도달될 때까지의 시간을 측정해 ECBC의 계산식에 의한 지속시간과 실제 데이터를 통해 산출한 지속시간도 같이 비교해 데이터의 신뢰성을 확인하였다. 지속도 데이터와 증기농도 및 흡입량을 기준으로한 위험기준을 토대로 지속시간 기준별 위험수준을 확인했고, 잔류량 분석을 통해 잔류위험을 확인하였다. 분석결과 화학작용제의 증기량이 미미한 시점에서도 잔류위험이 존재하는 것으로 확인되었다.