Lee Kuan Yew Distinguished Visitors Programme - Public Lecture Series

About the speaker

Professor Makoto Fujita, Distinguished University Professor, The University of Tokyo

Makoto Fujita is a Distinguished University Professor at Tokyo College, The University of Tokyo, Japan. He earned his Ph.D. from the Tokyo Institute of Technology in 1987. After holding positions at Chiba University and the Institute for Molecular Science (IMS) in Okazaki, he became a full professor at Nagoya University in 1999. In 2002, he moved to The University of Tokyo, where he was appointed a full professor. He received his current title as a University Distinguished Professor in 2019.

He is a recipient of the 2018 Wolf Prize in Chemistry, and became a foreign honorary member of the American Academy of Arts and Sciences (AAAS) in 2025.

About the topic

Molecular self-assembly based on coordination chemistry has undergone explosive development in recent years. Since 1990, our research has demonstrated that the simple combination of the geometry of transition metals (typically, the 90-degree coordination angle of a Pd(II) centre) with organic bridging ligands enables the quantitative self-assembly of nano-sized, discrete organic frameworks. Representative examples include square molecules (1990), linked-ring molecules (1994), cages (1995), capsules (1999), and tubes (2004), all of which are self-assembled from simple and small components.

Molecular Confinement Effects in Coordination Cages

Size plays a crucial role in host-guest chemistry. In the early days, crown ethers and macrocyclic hosts identified metal ions and small molecules within their cavities. However, due to size constraints—typically, <200 ų cavity volume—these synthetic hosts could mostly recognise a single small molecule, rarely exhibiting unique properties. Since the mid-90s, we and others (Rebek, Raymond) have developed larger, three-dimensionally closed cavities by harnessing the principle of molecular self-assembly. The M6L4 cage with an octahedral shape is one of the most effective self-assembled hosts, offering a molecular recognition site with an approximate cavity volume of 450 ų. The cavity, surrounded by four hydrophobic and electron-accepting ligands, effectively accommodates multiple guest molecules, forming conformationally fixed guest aggregates that enable new reactions and functions. Recently, we successfully built an expanded M9L6 cage (cavity volume >1500 ų) using the same components, while maintaining the strong guest-binding abilities of the M6L4 cage. This cage can fully encapsulate medium-sized molecules (M.W. 1000–2000), which are of particular interest in pharmaceuticals. Self-assembly of MnL2n gigantic cages (n = 12, 24, 30, 48) as well as protein encapsulation within the M12L24 cages will also be discussed in this talk.

Moderated by Prof Liu Xiaogang, Distinguished Professor, Department of Chemistry at Faculty of Science and Department of Surgery at Yong Loo Lin School of Medicine, NUS