Research Abstract

@Fascination to learn about the nature of the elements and molecules and to control their behavior goes back to ancient times. The research programs in our laboratories focus on the development of new and efficient synthetic reactions, new reactive molecules, and new chemical principles that will exert impact on the future of chemical, biological and material sciences. Under the specific projects listed below, we seek for the new paradigm of chemical synthesis and functional molecules. Discovery based on logical reasoning and imagination is the key term of our research and educational programs.

Research Projects

Science of Functional Carbon Clusters

@Carbon cluster compounds such as fullerenes and carbon nanotubes are among the most promising materials in nanotechnology. We have been involved in the development of new methods to functionalize such carbon cluster compounds and their application to nanoscience. One of our key methods is quantitative five-fold addition of an organocopper reagent to C60, with which we have synthesized a number of intriguing functional molecules such as: fullerene-metal complexes including hybrids with ferrocene ("bucky ferrocene" and "double-decker bucky ferrocene"), a hoop-shaped hydrocarbon "cyclophenacene" ("the shortest carbon nanotube"). We can also contorl molecular aggregation of pentaorganofullerene compounds through self-assembly, thereby produce nanomaterials such as water-soluble bilayer vesicles and nano-shuttlecock liquid crystals. Water-soluble fullerenes have been successfully applied as a transfection agent.
As for nanotube chemistry, we have been so far engaged in the synthesis of nanotube-metal hybrid materials and sunthesis of their application to magnetic resonance imaging, and water-soluble nanotubes and assessment of toxicity of such nanomaterials.

New Functionalized Organometallics and Their Application to Materials Science

@Development of versatile reactive species is a fundamental subject in synthetic organic chemistry. We have been exploring new reactive species with particular focus on carbanion chemistry, and thus far devised novel carbanion species including naked ammonium enolate and metal homoenolates. More recently, we have embarked on a program of gElement Strategyh, where we aim to replace precious and toxic metal catalysts with base metal catalysts such as iron or cobalt. We place a particular focus on the development of step-efficient reactions such as C-H bond functionalization.
Furthermore, we have devised new methods for the preparation of benzofuran and indole derivatives through intramolecular addition of zinc alkoxide/amide to alkynes. The 3-zinciobenzofuran/indole species opened up routes to novel polysubstituted benzoheterole derivatives that will find applications to molecular electronics. These studies are performed under the auspices of the S-Innovation program: "The Development of New Technologies Based on Organic Materials" , and through active collaboration with Mitsubishi Chemicals.

Mechanism of Organic/Organometallic Reactions

@Simple-looking synthetic reactions such as Grignard reaction are not at all simple, since numerous equilibrating metal clusters are involved in the reactions. This program focuses on the elucidation of the mechanism of important synthetic and catalytic reactions with the aid of extensive theoretical calculations. We have been particularly focusing our interest on the synergy of multiple metal elements involved in transition metal/main group metal combined systems and multinuclear transition metal catalysis. One of the most notable achievements in this area is mechanistic study of a series of synthetic transformations with organocopper reagents. On the basis of the theoretical studies, we are aiming at the rational design of functional molecules and catalysts.

@An isolated molecule has been an "imaginary entity" that can only be studied theoretically, since the most of common analytical methods such as NMR, IR, X-ray analysis give us an averaged picture of vast molecules. We are recently challenging the imaging of small organic molecules with the aid of high-resolution transmission electron microscope (TEM), under the auspices of the CREST program: "Establishment of Molecular Technology towards the Creation of New Functions". Using the HR TEM technique, we could directly visualize the movement of molecules and their conformational changes, chemical reactions such as dimerization of fullerene and iron-mediated reactions, the crystallization process of organic molecules, etc.