Seminars 2020

Title:Radical-Mediated Organocatalysis
Speaker:Professor Hirohisa Ohmiya
Date:11 December 2020
Time:2.00 pm to 3.30 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Naohiko Yoshikai
Abstract: In this presentation, we describe new radical-mediated organocatalysis. This is based on the organocatalyst design focusing on the reaction pathway involving a single electron transfer followed by a radical–radical coupling. For example, N-heterocyclic carbene catalysis promoted the decarboxylative coupling of aldehydes and tertiary or secondary alkyl carboxylic acid-derived redox-active esters to produce ketones. A reaction pathway involving single electron transfer from an enolate form of Breslow intermediate to a redox ester followed by recombination of the resultant radical pair to form a carbon–carbon bond is proposed. More recently, organophotoredox-catalyzed C(sp3)–heteroatom formation was achieved. Decarboxylative coupling between simple aliphatic alcohol, amine or thiol nucleophiles and tertiary or secondary alkyl carboxylic acid-derived redox active esters through visible light-mediated organosulfide catalysis produced a C(sp3)–X–C(sp3) (X = oxygen, nitrogen and sulfur) fragment. The reaction involves a radical-polar crossover process, which enables the generation of a carbocation from a carbon radical.

 

Title:Processed Food, Energy Intake and Health; Challenges and Opportunities
Speaker:Dr Ciarán Forde
Date:30th October 2020
Time:1.00 pm to 2.30 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Ken Lee

 

Title:Stereocomplex Crystallization of Polymers: From Crystallization Mechanism to High-performance Materials
Speaker:Professor Pengju Pan
Date:23th October 2020
Time:3.00 pm to 5.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Professor Atsushi Goto
Abstract:

Stereocomplex crystallization of enantiopure polymers is a special cocrystallization manner of macromolecules. Due to the unique crystalline structure, the stereocomplexed materials have many merits such as the high melting point, thermal resistance, crystallizability, better mechanical properties and hydrolytic resistance compared to the homocrystalline materials. However, stereocomplex crystallization usually competes with the homocrystallization in the crystallization process; this impacts the preparation of stereocomplexed materials with high performance. Furthermore, it is still challenge to use the stereocomplex crystallization to construct the functional polymer materials. In this talk, we select poly(lactic acid) as a representative stereocomplexed polymer and introduce the crystallization mechanism, structural evolution and phase transition in the stereocomplex crystallization. Furthermore, the use of stereocomplex crystallization to control the microstructure and physical property of polymer micelles, hydrogels, and elastomers will be also presented.

References: 1) Zheng, Y.; Pan P. J. Prog. Polym. Sci. 2020, 109, 101291. 2) Xie, Q.; Bao, J. N.; Shan, G. R.; Bao, Y. Z.; Pan, P. J. Macromolecules 2019, 52, 4655-4665. 3) Zhou, J.; Cao, H. Q.; Chang, R. X.; Shan, G. R.; Bao, Y. Z.; Pan, P. J. ACS Macro Lett. 2018, 7, 233-238.

 

Title:New Technological Approaches to Blood Coagulation Monitoring
Speaker:Professor Tony Killard
Date:20th October 2020
Time:4.00 pm to 6.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Alessandra Bonanni
Abstract:

New technologies, particularly point-of-care diagnostic devices have had a significant impact on the management of chronic health conditions, such as diabetes. Several approaches based on sensors have been developed for measuring a range of biological markers of disease, many of which are adaptations of laboratorybased assays. These have focused on the use of enzyme-based sensors, or affinity-based devices based on protein (e.g., antibodies) or nucleic acid (e.g., DNA) interactions.

One area of disease management has been less studied. Haemostasis is the body’s mechanisms to prevent bleeding. Imbalance in this process can lead to excessive bleeding, or excessive clotting, and can cause significant morbidity and mortality. Most testing is still performed in the hospital laboratory. However, moving testing to point-of-care could assist disease management very significantly.

In this presentation, I will detail some of the challenges associated with both bleeding and thrombotic disorders, and present some of the approaches my research has taken to developing novel point-of-care tests and devices to address some of these challenges, including lateral flow technologies, QCM approaches, and, most recently, the development of paper-based devices for use in low resource economies.

 

Title:Using Raman Scatter from Single Cell to predict the Cell State
Speaker:Dr Hideaki Fujita
Date:16th October 2020
Time:3.00 pm to 5.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Ken Lee
Abstract:Mammalian cells can take various states depending on their role which will change by the que from the environment. Traditional methods to detect cell state such as Western blot analysis, quantitative RT-PCR or immunofluorescent microscopy, where cells will be distracted during analysis. Microscopy using reporters or FACS using surface markers enable to detect the cell state without distraction, however, comprehensive analysis is difficult due to the limitation of the number of reporters that can be used. In this seminar, I will introduce Raman scattering analysis to predict the cell state without labeling and cell distraction. Using Raman scattering from a cell, celltype, cell differentiation, cell activation can be predicted.

 

Title:Protein Chemistry, Analysis and Medicine
Speaker:Professor Sunny Zhou
Date:9th October 2020
Time:10.00 am to 12.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Li Tianhu
Abstract:In this talk, Sunny will share his ongoing work and potential opportunities for collaboration. His laboratory, aka SunnyLand, applies protein chemistry, analysis and engineering to biology and medicine. One program is “Hybrid Modality Engineering of Proteins”—a platform to introduce non-canonical chemical moieties and/or scaffolds into peptides and proteins to confer novel functions otherwise unavailable via recombinant technology. For instance, his group has developed a new method to activate proteins by light (photocaging). The second program is to devise chemo-enzymatic methodologies to characterize protein modifications, such as crosslinking (e.g., affinity labeling), isoaspartic acid formation (asparagine deamidation) and S-adenosylmethionine (AdoMet or SAM)-dependent methylations. In collaboration with biologists and clinicians alike, we also investigate their biological effects, and moreover, as critical attributes in protein pharmaceuticals. The third program area is the mechanistic studies of and inhibitor design for enzymes with intriguing mechanisms and biomedical significance.

 

Title:AI-Assisted Chemical Synthesis
Speaker:Assistant Prof Connor W. Coley
Date:18th September 2020
Time:09.00 am to 11.00 am
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Lu Yunpeng
Abstract:Drug discovery is an enormously complex multi-objective optimization problem. Machine learning and artificial intelligence techniques are increasingly used in the design of new compounds, yet the synthesis of those compounds continues to be a predominantly manual task. This talk will describe ongoing efforts to streamline the design, validation, and implementation of small molecule synthetic routes through a computational understanding of synthetic chemistry learned from the chemical literature. We have developed an open source software suite, ASKCOS, that is capable of proposing retrosynthetic routes to new molecules, proposing reaction conditions for each step, and assessing the likelihood of experimental success. A proof-of-concept demonstration shows how these tools, in combination with laboratory automation and robotics, can streamline chemical development.

 

Title:Carotenoid-mediated light harvesting in plants
Speaker:Associate Professor Gabriela Schlau-Cohen
Date:11th September 2020
Time:10.00 am to 12.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Tan Howe Siang 
Abstract:Plants absorb sunlight across the visible region of the solar spectrum and then, through complex kinetics, collect the energy required for photochemical reactions in lower-lying states. 2D electronic spectroscopy measures both excitation energy and emission energy with femtosecond temporal resolution and therefore is a powerful tool to disentangle complex kinetics. However, previous 2D experiments to study plants have been limited to the dynamics of the low-energy states, leaving the higher-energy states unexplored. We describe the development of ultrabroadband 2D electronic spectroscopy and its application to map out the excited states and dynamics of the major antenna complex of plants across the visible region. First, by analyzing the vibrational wavepackets in the spectra, we identify a debated dark state on a single carotenoid, lutein 2, that mediates relaxation. This result reveals that the protein binding pocket can control the electronic structure of carotenoids, and therefore their function in photosynthesis. Second, we measure chlorophyll-to-carotenoid energy transfer, a hypothesized but previously unobserved pathway to safely dissipate excess energy. This dissipative pathway provides a mechanism by which plants can flourish despite fluctuations in sunlight, i.e. on both sunny and cloudy days.

 

Title:Innovation and Commercialisation Strategy: From Lab Prototype to Market
Speaker:Mr David Toh
Date:4th September 2020
Time:10.00 am to 12.00 pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Ling Xing Yi 
Abstract:Interested to learn more about commercialising your inventions? What are the benefits and pitfalls of starting your own company, versus licensing the technology to a third party? What should you look out for before you launch your startup and what are the resources available to prepare yourself should you choose this path? What are some of the common pitfalls you should avoid as a university startup, if you are starting a business? The aim of this talk is to provide faculty and researchers with some background knowledge on how to go about commercialising their technology inventions. Not all innovations are suited for starting companies, and sometimes the better strategy is to license the technology to a third party SME or MNC. If you have chosen the path of starting a business, we will walk you through the various stages of financing your startup, including discussion on grants, external investor funding, and some basic valuation principles. We will also discuss free resources available for you to tap into at NTUitive to better prepare yourself before launching the business. Last, we will also articulate strategies needed to build a successful and scalable tech startup.

 

Title:Partitioning polymers and where to find them: in situ product recovery of fragrances and organic acids in TPPBs
Speaker:Dr Eric Charles Peterson
Date:28th August  2020
Time:4.00pm to 5.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Ken Lee
Abstract:Downstream purification is a major component of fermentation costs, and by facilitating in situ product recovery (ISPR) via direct inclusion of absorptive polymers, two phase partitioning bioreactors (TPPBs) afford significant process benefits. Specifically, absorption into solid polymer pellets allows for mechanical removal from fermentation broth and avoids emulsification associated with traditional liquid organic solvents, simplifying downstream purification and reusability. Additionally, both solid and liquid absorptive phases reduce end-product inhibition arising from the accumulation of target molecule concentrations, which improves both bioprocess rates and yields. This approach has been applied to a range of biologically produced molecules, and is currently being used at SIFBI for the bioproduction of fragrances including viridiflorol, ionone, and linalool. However, partitioning with soft polymers is not without challenges, and work must be done to further characterize optimal polymer composition and physical properties to achieve desirable uptake. This talk will outline the steps taken to develop a rational, first-principles approach to predicting thermodynamic affinity of a polymer for a given target molecule, while also considering polymer properties necessary for rapid and effective uptake. Furthermore, work done for more challenging molecules such as organic acids, which exhibit pH-dependent partitioning, will be considered, and approaches and novel reactor designs to facilitate ISPR of these important molecules, and how they could be applied to mixed-culture biomass conversions will also be covered.

 

Title:Small Molecule Activation at Transition Metal Centers: Structure-Function Correlations
Speaker:Professor Kallol Ray
Date:14th August  2020
Time:4.00pm to 5.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Soo Han Sen 
Abstract:Small molecule activation constitutes one of the main frontiers of inorganic and organometallic chemistry, with much effort directed towards the development of new processes for the selective and sustainable transformation of abundant small molecules such as dioxygen (O2 ), water (H2O), hydrogen peroxide (H2O2 ) or protons (H+ ) into high-value chemical feedstocks and energy resources. Because nature mostly uses metal ions to activate these relatively inert molecules and modulate their reactivity, much inspiration for the field has come from bioinorganic chemistry. This talk will focus on some of the recent highlights from our group on homogenously catalyzed bioinspired activation of small molecules, as well as stoichiometric reactions that further our understanding towards such ends. It will cover many aspects of small molecule activation including: organometallic chemistry, spectroscopy, synthesis, and detailed mechanistic studies involving trapping of reactive intermediates. The demonstrated examples will help to emphasize the continuous effort of our group in uncovering the structure-reactivity relationships of biomimetic model complexes, which may allow vital insights into the prerequisites necessary for the design of efficient catalysts for the selective functionalization of unactivated C–H bonds, O2 /H2O/H2O2 activations, or H+ reductions by using cheap and readily available first-row transition metals under ambient conditions.

 

Title:Specificity, Function and Regulation of Protein O-GlcNAc Modification
Speaker:Associate Professor Jiaoyang Jiang
Date:14th August  2020
Time:9.00am to 10.30am
Venue:Zoom (ID and PW will be given upon registration)
Host: Assistant Professor Qiao Yuan 
Abstract:The N-acetylglucosamine (O-GlcNAc) modification is an essential glycosylation that has been identified on over 1,000 proteins. It dynamically modulates protein functions and regulates numerous biological processes in physiology and disease. O-GlcNAc modification is added by O-GlcNAc transferase (OGT) and removed by OGlcNAcase (OGA). Despite recent progress, challenges remain to decipher the biological roles of O-GlcNAc modification and its regulation by OGT and OGA on a broad range of substrates that lack an apparent sequence motif. In this talk, I will present our recently developed structural biology and chemical biology strategies to start revealing the specificity, function and regulation of O-GlcNAc modification.

 

Title:Annulative π-Extension Chemistry (APEX): Precise and Rapid Synthesis of Nanographenes and Graphene Nanoribbons
Speaker:Associate Professor Hideto Ito
Date:24th July 2020
Time:2.00pm to 3.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Assistant Professor Ito Shingo
Abstract:

Annulative π-EXtension (APEX) has emerged as a powerful and efficient synthetic method for the construction of polycyclic aromatic hydrocarbons (PAHs), nanographenes, and heteroatom-containing polycyclic aromatic compounds.1 In contrast to classical multi-step syntheses requiring substrate prefunctionalization, APEX reactions minimize the number of preparative steps by direct C–H functionalization of small aromatic templates. Since we defined ‘APEX’ as a novel synthetic concept in 2015,2a we have developed a series of palladium-catalyzed APEX reactions using various π-extending agents such as dibenzosilole 2a,b and diiodobiaryls,2c,d and enabled one-step PAH-tonaographene π-extensions in a fashion of direct C–H functionalization. In addition, we succeeded to develop sequential APEX reactions, i.e. APEX polymerization3 for the precise synthesis of graphene nanoribbons with controlling over edge-structure, width and even length, which has been otherwise difficult to synthesize by conventional methods.3a In the presentation, our recent reports on APEX chemistry for precise synthesis of nanographenes and graphene nanoribbons will be presented.2,3

References (1). (a) Ito, H.; Ozaki, K.; Itami, K. Angew. Chem., Int. Ed. 2017, 56, 11144. (b) Ito, H.; Segawa, Y.; Murakami, K.; Itami, K. J. Am. Chem. Soc. 2019, 141, 3. (2). (a) Ozaki, K.; Kawasumi, K.; Shibata, M.; Ito, H.; Itami, K. Nature Commun. 2015, 6, 6251. (b) Shibata, M.; Ito, H.; Itami, K. J. Am. Chem. Soc. 2018, 140, 2196. (c) Matsuoka, W.; Ito, H.; Itami, K. Angew. Chem. Int. Ed. 2017, 56, 12224. (d) Kitano, H.; Matsuoka, W.; Ito, H.; Itami, K. Chem. Sci. 2018, 9, 7556. (e) Kawahara, K. P.; Matsuoka, W.; Ito, H.; Itami, K. Angew. Chem., Int. Ed. 2020, 59, 6383. (3). (a) Yano, Y.; Mitoma, N.; Matsushima, K.; Wang, F.; Matsui, K.; Takakura, A.; Miyauchi, Y.; Ito, H.; Itami, K. Nature 2019, 571, 387. (b) Yano, Y.; Wang, F.; Mitoma, N.; Miyauchi, Y.; Ito, H.; Itami, K. J. Am. Chem. Soc. 2020, 142, 1686. (3) Mitoma, N.; Yano, Y.; Miyauchi, Y.; Ito, H.; Itami, ACS Appl. Nano Mater. 2019, 2, 4825.

 

Title:Chemical Approaches for Deciphering Glycosylation
Speaker:Professor Xing Chen
Date:24th July 2020
Time:10.00am to 11.30am 
Venue:Zoom (ID and PW will be given upon registration)
Host: Assistant Professor Qiao Yuan
Abstract:

As one of the major biomacromolecules, glycans mediate various important physiological and pathological processes. On the other hand, glycans are highly complex and heterogeneous. As a result, unlike nucleic acids and proteins, powerful tools for analyzing and profiling glycosylation are relatively lacking. Chemical methods can help address these challenges. For examples, metabolic glycan labeling has emerged as a central tool for glycan imaging and glycoproteomic profiling in live cells and living animals. Our group has developed several chemical tools to elucidate the biological function of glycosylation, with an emphasis on in vivo labeling, visualization, and profiling of glycosylation dynamics. We are particularly interested in how glycosylation regulates the physiology and pathology in the brain and during development. In this talk, I will introduce some of the recent progresses in this direction.

 

Title:Going with the Flow - The Use of Continuous Processing in Organic Synthesis
Speaker:Professor Oliver Kappe
Date:17th July 2020
Time:4.00pm to 5.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Ken Lee 
Abstract:Continuous flow processes form the basis of the petrochemical and bulk chemicals industry where strong competition, stringent environmental and safety regulations, and low profit margins drive the need for highly performing, cost effective, safe and atom efficient chemical operations. In contrast to the commodity chemical industry, however, the fine chemical industry primarily relies on its existing infrastructure of multipurpose batch or semi-batch reactors. Fine chemicals, such as drug substances and active pharmaceutical ingredients (APIs), are generally considerably more complex than commodity chemicals and usually require numerous, widely diverse reaction steps for their synthesis. These requirements generally make versatile and reconfigurable multipurpose batch reactors the technology of choice for their preparation. However, the advantages of continuous flow processing are increasingly being appreciated also by the pharmaceutical industry and, thus, a growing number of scientists, from research chemists in academia to process chemists and chemical engineers in pharmaceutical companies, are now starting to employ continuous flow technologies on a more routine basis [1]. Flow technology has considerable advantages in mass- and heat transfer, safety and ease of scale-up, when compared to traditional batch reactions. Furthermore, hazardous chemistries such as highly exothermic reactions, or those involving unstable or toxic intermediates can be operated safely in flow, whereby this technology acts as a powerful route-enabler. In this lecture, contributions from our research group in the field of continuous flow processing will be highlighted. Emphasis will be given to highly atom efficient and process intensified chemical transformations useful for the synthesis of APIs or key intermediates that are often too hazardous to be executed in a batch reactor. These involve azide, diazomethane and nitration chemistry, oxidation reactions involving pure oxygen, and flow photochemistry/electrochemistry applications.

 

Title:Single-molecule Catalysis: Nanoparticles and Polymers
Speaker:Professor Peng Chen
Date:3rd July 2020
Time:10.00am to 11.30am 
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Zhang Zhengyang
Abstract:This presentation will describe our efforts in developing single-molecule approaches to study catalysis, focusing on two stories. The first story will be about our single-molecule fluorescence imaging work on the catalytic properties of individual nanoparticles at single-turnover resolution and nanometer precision. I will describe the insights we gained into the catalytic activity and dynamics of individual metal nanoparticles, and the surprising spatial and temporal activity patterns and dynamics within single nanocatalysts. The second story will be about our work in using magnetic tweezers to track single polymer growth in real time under living polymerization catalysis conditions. I will describe how the real-time growth dynamics of single polymers reveal the formation and unraveling of conformational entanglements that play key roles in the polymerization kinetics and kinetic dispersion among individual polymers.

 

Title:Lessons from Simulation of Time-Resolved Spectroscopy on Light-Harvesting Systems
Speaker:Assistant Professor Thomas La Cour Jansen
Date:26th June 2020
Time:3.00pm to 4.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Tan Howe Siang 
Abstract:Natural light-harvesting systems as found in plants, algae, and especially bacteria are efficient in absorbing photons and transporting their energy to reaction centers, where the energy is converted to chemical energy. Time-resolved spectroscopy allow the detailed study of the mechanism and dynamics of the light harvesting process. However, these spectra are often congested and challenging to interpret. I will discuss how simulations can be used to distinguish between different processes including energy transport, exciton delocalization, electronic coherence, nuclear coherence, and exciton annihilation. Increasingly detailed models of light-harvesting systems allow increasingly refined understanding of the molecular scale dynamics directing the light-harvesting process. Some of these lessons may aid the design of future artificial light-harvesting systems for photo-voltaic applications or for improving crop yield.

 

Title:Catalysis of Transition Metal Complexes in Water Splitting and CO2 Reduction: Improved Understanding in the Reaction Pathways
Speaker:Professor Ken Sakai
Date:19th June 2020
Time:1.00pm to 2.30pm 
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Soo Han Sen 
Abstract:Since the initial discovery in 1987 (J. Coord. Chem. 1988, 18, 169) in the catalytic activity of platinum(II) compounds in hydrogen evolution reaction (HER), continued efforts have been made to gain deeper understanding in the mechanism of molecular catalysis by various transition metal compounds in some important energy related catalytic reactions such as HER, OER (oxygen evolution reaction), and carbon dioxide reduction (CDR). For the reduction side of catalysis (HER and CDR), the manner how we utilize/tune either the electron density or basicity at the filled d orbital exposed at the reaction center plays a key role in promoting the protonation or CO2 -binding step which is often the rate-determining steps (RDSs). In such RDSs (i.e., M(d8 ) + H+  M(d6 )(H)+ or M(d8 ) + CO2  M(d6 )(CO2 2-)), the filled dz2 orbital in a square-planar or distorted square pyramidal d8 metal ion is generally required with a limited number of exceptions, which has become increasingly clearer based on our recent Experimental/DFT hybrid studies. The d8 Pt(II), Ni(II), Co(I), and Rh(I) are good candidates due to their easily accessible characters under ambient or weakly reducing conditions. However, these systems often require further reduction at the metal-ligand or ligand orbitals that are closely located to the reactive metal center, in part due to the lack of driving force to promote the HER or CDR. On the other hand, Fe(0) and Mn(-I) are also known to be useful candidates only when they are coordinated by strongly π-back bonding ligands such as carbon monoxide (CO), as demonstrated by the naturally evolved [FeFe]-hydrogenase enzyme and Mn(bpy)(CO)3Br. However, with the lack of CO-like ligands stabilizing such low valent systems, Fe(0) requires relatively strongly reducing conditions and thereby exhibits slow catalysis when driven by the standard photosensitizers like Ru(bpy)3 2+ or organic dyes due to the insufficient driving forces available for the reactive intermediate formation step.

 

Title:Behavior of Molecules: From Catalysis to Biological Functions
Speaker:Professor Takashi Ooi
Date:12th June 2020
Time:5.00pm to 6.30pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Professor Chiba Shunsuke 
Abstract:Molecules are the smallest units responsible for functions and are inherently multidisciplinary as fields that deal with structurally well-defined molecular entities are diverse. Synthetic chemistry is essential for the assembly of molecules by connecting or breaking bonds in a predictable manner. Such endeavor always involves the transformations of certain carbon feedstock to desired products. In developing ideal systems for executing this fundamental process, catalysts play a pivotal role. In this context, we have designed and synthesized a series of structurally novel organic molecules, particularly chiral organic ion pairs as shown below, and succeeded in eliciting their unique functions as molecular catalysts and ligands through rational structural modifications, thereby leading to achieve highly selective bond-forming reactions based on the precise control of ionic species. In this lecture, I will present the details of this research stream with focus on the recent advance. I will also discuss about our collaborative research with biologists at ITbM, such as molecular-level approach to combat Striga, a parasitic plant causing huge damage in Africa agriculture.

 

TitleNew-to-nature Chemical Tools for Studying Glycans and its Transport
Speaker:Assistant Professor Ran Xie
Date:5th June 2020
Time:9.00am to 11.00am
Venue:Zoom (ID and PW will be given upon registration)
Host: Professor Chiba Shunsuke 
Abstract:Glycosylation plays pivotal roles in various cellular processes. Employing new-to-nature chemistry to decipher biological functions of glycan, as well as to fulfil glycan-based therapeutic need, remains a major challenge. In this virtual seminar, we present the development of a liposome-assisted bioorthogonal reporter strategy (LABOR) to achieve selective visualization and detection of eukaryotic glycans both in vitro and in vivo. A brief report on how cutting-edge chemical tools are used to study the transport process of lipopolysaccharide (LPS), a prokaryotic cell surface glycan, will also be discussed.

 

TitlePowering Selective Oxidations of Organic Molecules with Renewable Energy
Speaker:Dr Leow Wan Ru
Date:3rd June 2020
Time:11.00am to 12.30pm
Venue:Zoom (ID and PW will be given upon registration)
Host: Dr Lee Hiang Kwee
Abstract:

The partial oxidation of organic molecules is an important class of reactions for the production of everyday commodities. An example is the polyethylene terephthalate (PET) plastic found in our drinking bottles – the precursors oxirane and terephthalic acid are produced from the partial oxidation of ethylene and xylene at 20 and 60 million tons per annum. Every year, 1.8 billion tons of CO2 are emitted due to the dependence of such partial oxidations on fossil-fuel-powered thermal control, as well as the tendency of these hydrocarbons tend to oxidize all the way to CO2.1 If we can develop high selectivity partial oxidations that are powered by renewable energy, we will be able to cut these associated CO2 emissions by half.2 In this talk, I will first discuss the activation of different functional groups on heterogeneous surfaces, to enable photocatalytic electron transfer under ambient and benign conditions.3-4 Key insights for rational surface engineering of heterogeneous photocatalytic materials to achieve partial oxidations for pharmaceuticals and fine chemicals will also be described. The second part will be focused on electrochemical partial oxidation at breakthrough current densities (1 A/cm2) by extending the reaction interface from the electrode surface with a charge mediator.5 These studies open opportunities for the development of alternative chemicals manufacturing routes towards a sustainable and decarbonized economy. For Zoom registration:

References 1. Boulamanti, A., Moya, J. A. Energy efficiency and GHG emissions: Prospective scenarios for the Chemical and Petrochemical Industry. 2017. 2. Zheng, J., Suh, S. Strategies to reduce the global carbon footprint of plastics. Nat. Clim. Change. 2019, 9 (5), 374-378. 3. Leow, W. R., Chen, X. et. al. Al2O3 surface complexation for photocatalytic organic transformations. J. Am. Chem. Soc. 2017, 139 (1), 269-276. 4. Leow, W. R., Chen, X. et. al. Correlating the surface basicity of metal oxides with photocatalytic hydroxylation of boronic acids to alcohols. Angew. Chem. Int. Ed. 2018, 57 (31), 9780-9784. 5. Leow, W. R., Lum, Y., Sargent, E. H. et. al. Selective ethylene oxide electrosynthesis at high current density enabled by a chloride mediator. Science, Accepted 2020.

 

TitleEngineering the Interfaces between the Encapsulated Catalysts and Metal-organic Frameworks
Speaker:Assoc. Prof Chia-Kuang Frank Tsung
Date:22nd May 2020
Time:9.00am to 10.30am 
Venue:Zoom (ID and PW will be given upon registration)
Host: Associate Professor Ling Xing Yi 
Abstract:

Heterogeneous catalysis is critical for the prosperity of human civilization.It provides access to the range of chemicals, materials, and fuels we use. Towards the long-term vision of precisely controlling active sites, our group focuses on incorporating various catalysts into crystalline nanoporous materials, metal-organic frameworks (MOFs). The precise molecularly-defined pores intrinsic to the MOFs provide a new tool to control the catalytic transformations on the catalysts. We have developed methods to combine organometallic catalysts, enzymes, and nanoparticle catalysts with MOFs of precisely tuned pore structures to manipulate the reactions.

 

TitleChemical Biology Tools for Studying Crowding Multimolecular Biosystems: Fluorescent Probes and Peptide Ligands
Speaker:Dr Takuya TERAI
Date:7th February 2020
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Conference Room
Host: Professor Xing Bengang 
Abstract:

Cells and tissues are crowding multimolecular biosystems wherein various biological molecules miscellaneously and densely co-exist in different compartments. Although traditional biochemistry extracts and purifies each component from the cells and reconstitutes the system of interest in a test tube, this approach cannot really understand dynamic and complex behaviors of biomolecules in real living systems. So, the ultimate purpose of my research is to establish a new and interesting chemical/biochemical molecular tools for functional analysis and artificial regulation of biomolecules in living systems. This will contribute to progress in chemical biology, drug discovery, and disease diagnosis. With this in mind, I have mainly worked on the development of two kinds of molecular tools so far: fluorescent probes and functional peptides. As to the former, I developed several fluorescent probes based on lanthanide complexes,1,2 organic small molecules,3 and small molecule-protein conjugates.4,5 These probes were rationally designed using the photochemical principles including intramolecular photoinduced electron transfer, and could be applied to cell imaging or drug discovery research. As to the latter, I focus on a molecular evolution technology called “cDNA display”, where a peptide and a nucleic acid that encodes it is covalently coupled via a specially designed puromycin DNA linker.6 I have recently identified peptides that associate with lipid membrane,7 an organic dye,8 and drug target proteins (unpublished). In this seminar, I will present these works and also discuss my future plan, where organic chemistry of small molecules and directed evolution of polypeptides are bridged in a true sense.

References 1. T. Terai et al. "A Long-Lived Luminescent Probe to Sensitively Detect Arylamine N-Acetyltransferase (NAT) Activity of Cells" Chem. Commun., 48, 2234-2236 (2012). 2. H. Ito, T. Terai* et al. "Detection of NAD(P)H-dependent Enzyme Activity with Dynamic Luminescence Quenching of Terbium Complexes" Chem. Commun., 51, 8319-8322 (2015). 3. T. Terai et al. "TokyoGreen Derivatives as Specific and Practical Fluorescent Probes for UDP-Glucuronosyltransferase (UGT) 1A1" Chem. Commun., 49, 3101-3103 (2013). 4. T. Hirata, T. Terai* et al. "A Protein-Coupled Fluorescent Probe to Visualize Potassium Ion Transition on Cellular Membranes" Anal. Chem., 88, 2693–2700 (2016). 5. R. Taguchi, T. Terai* et al. “A protein-coupled fluorescent probe for organelle-specific imaging of Na+” Sensor Actuat. B-Chem., 265, 575-581 (2018). 6. J. Yamaguchi et al. “cDNA display: a novel screening method for functional disulfide-rich peptides by solid-phase synthesis and stabilization of mRNA–protein fusions” Nucl. Acids Res., 37, e108 (2009). 7. S. Kobayashi**, T. Terai**, et al. “In vitro selection of random peptides against artificial lipid bilayers: a potential tool to immobilize molecules on membranes” Chem. Commun., 53, 3458–3461 (2017). ** equal contribution 8. T. Terai* et al., “Selection of Peptides that Associate with Dye-Conjugated Solid Surfaces in a pH-Dependent Manner Using cDNA Display”, ACS Omega, 4, 7378-7384 (2019).

 

TitleFunctionalizing Material Interfaces for Enhanced Analyte Detections and Gas-based Applications
Speaker:Dr Lee Hiang Kwee
Date:5th February 2020
Time:10.30am to 12.00pm 
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Associate Professor Ling Xing Yi 
Abstract:By combining different materials into a composite ensemble, the functionalities of individual components can be effectively integrated to design application-specific properties. This synergism offers a plethora of opportunities for the development of next-generation hybrid materials to address persistent limitations in real-world applications (such as in sensing and catalysis) that cannot be otherwise easily solved using a single-component material. In this talk, I will discuss on how we can create multifunctional hybrid platforms at liquid-liquid, solid-solid and solid-liquid interfaces to enhance analyte detections and gas-based applications. I will first demonstrate the use of particle-assembled microdroplets for the ultratrace and multiplex detection of analytes across a liquid-liquid interface at the molecular level. Next, I will discuss on creating a functional nano-interface between a solid surface and a metal-organic framework (MOF) to drive gas molecules into a pseudo high-pressure microenvironment directly at the point-of-use. This phenomenon notably enables efficient gas-based detection and reaction even at ambient conditions. Finally, I will introduce a designed solid-liquid interface for the low-cost and mobile detection of spectroscopically-silent heavy metal ions down to part-per-trillion levels.

 

TitleMedicinal Chemistry in the Search for Antibiotics with a New Mode of Action and Potentiators of CFTR Chloride Channel
Speaker:Professor Jean-Luc DECOUT
Date:22nd January 2020
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Assistant Professor Chen Gang 
Abstract:Numerous bacteria have developed resistance against aminosugar-based antibiotic drugs including neomycin B. In the search for novel antibiotic drugs acting on new targets, we have developed broad-spectrum membrane-targeting antibiotic compounds, through the modification of the antibiotic drug neomycin B. The synthesized neomycin B derivatives show high potency against the bacteria resistant to the existing antibiotic drugs of different classes. Antibiotic resistant lung bacterial infections are associated with the Cystic Fibrosis (CF) disease due to mucus thickening. CF is the most common lethal and inherited disease among Caucasians. CF results from more than 2000 identified mutations in both copies of the gene coding for Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, which is a chloride channel. I will present the medicinal chemistry of antibacterial neomycin derivatives and heterocyclic compounds developed for the identification of new CFTR modulators.

 

TitleStructure Characterisation of Bioactive Compounds and Their Interactions
Speaker:Dr Tomislav Jednacak
Date:21st  January 2020
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Assistant Professor Chen Gang 
Abstract:

Biomolecular interactions with high specificity and a significant degree of affinity play essential roles in all cellular processes such as gene regulation, molecular organisation, protein synthesis and recognition events. Determining the three-dimensional structure of macromolecules, ligands and their complexes is essential for obtaining a deeper insight into molecular mechanisms and dynamics involved in these interactions.[1,2] The first step to achieve this goal is the synthesis of various compounds, which can act as ligands for biomolecular receptors and thus regulate their function. In order to obtain the compounds with desired properties and optimise product yields, the syntheses can be monitored in real time by employing in-line vibrational spectroscopy and statistical methods.[3,4] Further analysis of complex reaction mixtures is carried out on-line using a hyphenated system which combines HPLC and SPE with cryo-NMR detection (HPLC-SPE/cryo-NMR).5 This approach is applied to monitor the reaction progress, explain the side-reaction mechanisms and unambiguously characterize the reaction components. In the next research stage, specific binding of the prepared ligands to macromolecules is investigated by a combined use of cryo-electron microscopy, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and NMR methods based on paramagnetic relaxation enhancements (PREs), saturated transfer difference (STD) and transferred nuclear Overhauser effect (trNOE). The results obtained for free and bound macrolide antibiotics and peptide nucleic acids (PNAs) can provide a wealth of information about the groups responsible for the binding, immersion depth, ligand conformation, binding modes and epitopes. Structural information is further combined with biochemical assays and biological tests to assess the structure-activity relationship and design the molecules with enhanced biological properties.

REFERENCES 1. I. M. A. Nooren, J. M. Thornton, EMBO J. 2003, 22, 3486. 2. R. Brigelius-Flohé, M. Maiorino, Biochim. Biophys. Acta 2013, 1830, 3289. 3. T. Jednačak, P. Novak, A. Hodzic, O. Scheibelhofer, J. G. Khinast, J. Plavec, P. Šket, J. Parlov Vuković, Acta Chim. Slov. 2014, 61, 161. 4. P. Novak, A. Kišić, T. Hrenar, T. Jednačak, S. Miljanić, G. Vrbanec, J. Pharm. Biomed. Anal. 2011, 54, 660. 5. I. Habinovec, T. Jednačak, P. Novak, ADMET & DMPK 2015, 3, 352.

 

Title7 Things You Never Knew About SciFinder-n…..
Speaker:Pamela Oon
Date:16th  January 2020
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Conference Room 
Host: -
Abstract:
  • Improve search efficiency with SciFinder-n’s relevance ranking
  • Locate patent information easily with PatentPak
  • Access experimental protocols directly with MethodsNow Synthesis
  • Generate new ideas for synthesis using Predictive Retrosynthesis
  • And more……

 

TitleNanyang Research Conference: Synthetic Chemistry and Catalysis
Date:15-17  January 2020
Venue:Nanyang Technological University, Singapore 
Host: Professor Chiba Shunsuke, Scientific Chair 

 

TitleSyntheses, Transformations and Applications of Organoboron Compounds
Speaker:Professor Song Qiuling
Date:14th  January 2020
Time:2.30pm to 4.00pm 
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Associate Professor Naohiko Yoshikai 
Abstract:

 

Since 1950’s, the reaction and functional transformations of organoboron compounds have made important achievements. Organoboron compounds have been widely used in the synthesis of natural products, drug candidates and large molecules with biological activity, besides, they have also been employed to materials sciences, catalytic chemistry as well as pharmaceutical chemistry.1 Focusing on the development of simple, efficient, green synthetic methods and new functional molecules, we have developed some reactions involving organoboron compounds,2 such as B-Cl/C-B cross-metathesis and C-H borylation reaction,2a stereospecific 1,4- migration reaction to obtain a stereochemically pure ketoxime,2b Pd-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides leading to various amidine salts as well as valuable diaryl ketones2c and a new chiral Brønsted acid, generated in situ from chiral phosphoric acid boron (CPAB) complex and water, for asymmetric indole reduction.2d

References 1. For an example of review: D. G. Hall, Boronic Acids: Preparation and Applications in Organic Synthesis Medicine and Materials, 2nd ed., Wiley-VCH, Weinheim 2011, pp. 427-477. 2. (a) Kai Yang, Guan Zhang and Qiuling Song*, Chem. Sci. 2018, 9, 7666; (b) Kai Yang, Feng Zhang, Tongchang Fang, Guan Zhang and Qiuling Song* Angew. Chem. Int. Ed. 2019, 58, 13421 –13426; (c) Shaoyu Mai, Wendong Li, Yingwei Zhao and Qiuling Song*, Nature Commun. 2019, in press; (d) Kai Yang, Yixian Lou, Chenglan Wang, LiangWen Qi, Tongchang Fang, Feng Zhang, Hetao Xu, Lu Zhou, Wangyang Li, Peiyuan, Yu,* Qiuling Song*, Angew. Chem. Int. Ed. 2019, 58, in press, DOI: 10.1002/anie.201913656

 

TitleMy Role within a Societal Publisher and Tips on how to Publish Your Scientific Research
Speaker:Dr Jeremy Allen
Date:13th January 2020
Time:11.00am to 12.30pm
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Professor Chiba Shunsuke 
Abstract: 

The Royal Society of Chemistry is one of the leading international chemical societies and it plays an important role within the community – helping to support those working in and studying the chemical sciences with a wide range of activities. During this presentation I will introduce the work that the Royal Society of Chemistry does, my role within the organization and the route I took from PhD student to being the Deputy Editor for Chemical Science. I will also highlight the role publisher’s play in the community and the benefits they can afford for supporting the dissemination of an author’s research output. Finally I will discuss the peer review and publication process, including how to choose a journal, getting your paper noticed and what to do after publication.

 

TitleCombining Theory and Experiment to Develop Selective C-C Bond Formations via Open-Shell Intermediates
Speaker:Professor Osvaldo Gutierrez
Date:8th January 2020
Time:2.30pm to 4.00pm
Venue:SPMS Research & Graduate Studies Conference Room 
Host: Professor Chiba Shunsuke 
Abstract:

Despite advances in high-throughput screening methods leading to a surge in the discovery of catalytic reactions, our knowledge of the molecular-level interactions in the rate- and selectivity-determining steps of catalytic reactions, especially those involving highly unstable and reactive open-shell intermediates, is rudimentary. These knowledge gaps prevent control, suppression or enhancement, of competing reaction channels that can drive development of unprecedented catalytic reactions. In this talk, I will focus on our use of high-level quantum mechanical calculations, rigorously calibrated against experimental data, to interrogate the mechanisms and to guide the development of new catalysts and reagents for currently sluggish or unselective reactions. In particular, I will focus on our use of combined experimental and computational tools to understand and develop new (asymmetric) iron-catalyzed and (metallo)photoredox-catalyzed carbon-carbon bond formations with relevance to the synthesis of pharmacetuticals.