NUS chemists made C-C coupling based 2D polymer
Professor Kian Ping Loh and PhD student Liu Wei in the Department of Chemistry, National University of Singapore, applied an ingenious strategy based on endogenous polymerization, carried out without catalyst, solvent or initiator, to make 2-D polymer based on C-C coupling reactions.
They discovered that pre-ordering well-designed, flat monomers into a single crystal structure can lead to a 2D crystalline aromatic polymer upon thermal annealing. The achieved polymeric sheets are parallel and can be readily exfoliated into micrometer-sized sheets with nanometer thickness, similar to the case of single-layer graphene. This approach paves the way towards the controlled synthesis of extended crystalline 2D conjugated materials for various applications. Due to its intra-sheet conjugation and ordered open 1D channel, the 2D polymer fabricated by Loh et. al. exhibits unprecedented cycle stability and rate capability when applied as an anode in an ambient temperature sodium cell. The work is published in Nature Chemistry. Read More.
Toward metallic molecular wires!
Graphene nanoribbons (GNRs) with a width < 10 nm have promising applications in the future nano-electronics. While semi-conducting GNRs can be applied as active components in field effect transistors, the metallic GNRs can be used as conducting wires. So far, the synthesis of GNRs with potential metallic properties is still not successful. In a recent publication in Chem, A/P Wu Jishan’s group reported the challenging synthesis and physical characterizations of a series of soluble and stable rylene ribbon molecules with the record length, which can serve as good model compounds of the narrowest armchair graphene nanoribbon. They observed very unusual open-shell diradical character for long rylene molecules, which can be correlated to the potential metallic property of the infinite polyrylene ribbon. This work was selected as a cover in the January issue.
President's Science Award 2016
Congratulations to A/P Liu Xiaogang for receiving the President’s Science Award 2016 for his outstanding research in developing rare-earth-doped nanocrystals that could be used as luminous tags for tracking cancer cells and deciphering various biologically relevant phenomena. Read More
Extended Bis(benzothia)-quinodimethanes and Their Dications: From Singlet Diradicaloids to Isoelectronic Structures of Long Acenes
In a recent article published in Angew. Chem. Int. Ed., 2016, 55, 9316-9320 (hot paper), (http://onlinelibrary.wiley.com.libproxy1.nus.edu.sg/doi/10.1002/anie.201603135/pdf), Dr. Chi and her co-workers synthesized a series of extended bis(benzothia)-quinodimethanes and their dications as stable species. The neutral compounds mainly have a quinoidal structure in the ground state but show increased diradical character with extension of the central quinodimethane unit. More importantly, the dications exhibit similar electronic absorption spectra, NMR spectra, NICS values, and diatropic ring currents to their aromatic all-carbon acene analogues and thus can be regarded as genuine isoelectronic structures of pentacene, hexacene and heptacene, respectively. This study provides a new way to design and synthesize stable longer acene analogues with similar electronic structures to the traditional all-carbon acenes.
Boronic Acid: A Bio-Inspired Strategy to Increase the Sensitivity and Selectivity of Fluorescent NADH Probe
Fluorescent probes have been widely used in the molecular recognition events in biological systems; however, it remains challenging to design small-molecule fluorescent probes sensitively and selectively sensing biomolecules with complex structures. Inspired by the enzyme-catalyzed reaction between biomolecule and probe, Prof. Chang and collaborators present a novel combination-reaction two-step sensing strategy to improve sensitivity and selectivity. Based on this strategy, they successfully prepared a boronic acid based fluorescent NADH (reduced nicotinamide adenine dinucleotide) probe and evaluate NADH levels in live cell imaging.
J. Am. Chem. Soc., 2016, 138 (33), pp 10394–10397
On-Chip Molecular Electronic Plasmon Sources Based on Self-Assembled Monolayer Tunnel Junctions
Surface plasmon polaritons (SPPs) confine and enhance local electromagnetic fields near surfaces of metallic nanostructures at optical frequencies and have the ability to propagate along sub-diffractive metallic waveguides opening-up new perspectives for integrated opto-electronic circuits at the nanoscale. To move beyond the currently available technologies, and to miniaturise the plasmonic devices, the group of Assoc Professor Christian A. Nijhuis and collaborators developed on-chip molecular electronic plasmon sources based on self-assembled monolayer (SAM) tunnel junctions. The new plasmon sources operate at molecular length scales and tunnelling time scales while the properties of the plasmons generated can be controlled via the molecular electronic properties of the junctions. This paves the way for future nanoscale optoelectronic information processing and computing.
Inaugural Chemistry Graduate Research Symposium
The inaugural Chemistry Graduate Research Symposium was organized by the Chemistry Graduate Society on 12 Aug 2016 at the University Hall. It was a one-day poster presentation event which a total of 71 Chemistry graduate and post-doctoral researchers presented their research work in front of their peers and the faculty members in the department. The participants were divided into 4 chemistry major research areas i.e. Analytical Chemistry and Energy/Environment; Physical Chemistry and Materials; Inorganic Chemistry and Catalysis; Organic, Medicinal, and Chemical Biology. Besides highlighting the participants’ achievements, this event also served as a platform for sharing cross-disciplinary ideas among different research groups and educating our undergraduates /graduate students about the research done in our department . The event was very well received and culminated in the presentation of seven travel awards by HoD, Prof Richard Wong, to students with the best posters as judged by an independent jury of faculty members based on their content, scientific merit and presentation. In addition, five “Peoples’ Choice” prizes were given out to the posters which garnered most votes from the participants.
Lunch appreciation for Mr Yeo Keng Joon and Mr Seah Cheng San
The Department of Chemistry has organized an appreciation lunch on Monday 15 Aug 2016 for Mr Yeo Keng Joon and Mr Seah Cheng San to express our gratitude for their help and support in establishment of Chemistry Alumni Fund since Nov 2015. A token appreciation was also presented to Mr Yeo for his contribution to the fund by establishing the “Chemistry Alumni – Yeo Keng Joon Study Award”.
The 48th International Chemistry Olympiad
The 48th International Chemistry Olympiad was held in Tbilisi, Georgia on July 23 – August 1, 2016 with 67 participating countries and 264 students. The Singapore team has been trained and led by Department of Chemistry staff, Dr. Zhang Sheng (Head Mentor) and Dr. Foo Maw Lin (Deputy Mentor). Singapore Team has won two gold medal (Nan Zhihan, NUSH and Wong Huai Zhe Matthew, RI) and two silver medals (Wang Kaiying, RI and Glen Goh Wee Zhuan, NUSH). The Singapore Team ranked 6th among the 67 participating countries. One of the students, Nan Zhihan, was also awarded with the IUPAC Prize for achieving the highest score in the experimental exam.
Chemistry Alumni Fund and Appreciation Dinner
Inspired and initiated by several of our senior alumni members, a fund-raising campaign to establish “Chemistry Alumni Fund” was started since Nov 2015. The main objective is to help and encourage outstanding bursary students through sub-named Study Awards. The campaign has received overwhelming support from our alumni and friends and was culminated with an “Chemistry Appreciation Dinner” on 27th May 2016 at NUSS Guild House. Altogether 12 sub-named Study Awards were set up and a total of $360k gifts were pooled together to establish this endowed Fund.
Metallkraft Singapore Pte Ltd has donated D2-Phaser instrument to X-Ray Diffraction Lab, Department of Chemistry.
Mr Teo, Managing Director of Metallkraft, and Professor Wong, Head of Department of Chemistry, signed the letter of transfer on 11 July 2016 to officiate the transfer.
Congratulations to Associate Professor Chen Wei for being appointed as Dean’s Chairs in the Faculty of Science.
NUS and Society of Environmental Toxicology and Chemistry will be jointly organizing the SETAC AP Singapore Conference to be held during September 16-19, 2016 at University Town, NUS. More information is available at: http://www.setac-singapore2016.org/index.html.
We welcome Class of ’62 Visiting Professor Rodney Scott Ruoff.