Molecular Architecture Laboratory

T. Yokozawa

Tsutomu Yokozawa
(Professor)

Office: 23-718-1 Ext.: 3846

e-mail: yokozt01@kanagawa-u.ac.jp

09/1987, Ph.D., Tokyo Institute of Technology

03/1983, M.S., Tokyo Institute of Technology

Y. Ohta

Yoshihiro Ohta
(Assistant Professor)

Laboratory: 23-719 Ext.: 3847

e-mail: y-ohta0112@kanagawa-u.ac.jp

03/2011, Ph.D., Kanagawa University

03/2009, M.S., Kanagawa University

Research Field

Synthetic Polymer Chemistry, Organic Chemistry.

Research Overview

Synthesis and reaction design of functional materials based on organic chemistry.

Research Subjects

    Precision synthesis and self-assembly of condensation polymers and p-conjugated polymers.

Introduction:

Many natural polymeric materials, such as proteins, are perfectly monodisperse macromolecules, and they are synthesized by the successive condensation of monomers with the polymer end group via selective activation by enzymes. The overall process can be regarded as a chain-growth condensation polymerization (CGCP). In contrast, conventional condensation polymerization proceeds by step-growth polymerization, producing polymers with a broad molecular weight distribution, and control over molecular weight and polymer end groups is difficult. We have achieved CGCP of artificial monomers to obtain well-defined condensation polymers and p-conjugated polymers by the following two approaches.

1. CGCP based on the substituent effect

When a substituent effect is changed by bond formation in a monomer, the reaction of a monomer with the polymer end functional group can be faster than that of the monomer with another monomer because the reactivity of the polymer end group is increased by the change in the substituent effect. We have obtained well-defined aromatic polyamides, polyethers, polyesters, and poly(ether sulfone)s by this approach. 

2. CGCP by catalyst transfer

Some coupling polymerizations with transition metal catalysts proceed by chain-growth polymerization through the successive intramolecular transfer of the catalyst to the polymer end group, affording well-defined p-conjugated polymers. These polymers have received much attention because of their applications in thin film transistors, organic light-emitting diodes, and organic photovoltaic cells. 

Publications
  • 1)T. Yokozawa and Y. Ohta, “Transformation of Step-Growth Polymerization into Living Chain-Growth Polymerization,” Chemical Reviews, vol. 116(4), pp. 1950–1968 (2016).
  • 2)M. Nojima, K. Kosaka, M. Kato, Y. Ohta, and T. Yokozawa, “Alternating Intramolecular and Intermolecular Catalyst-Transfer Suzuki–Miyaura Condensation Polymerization: Synthesis of Boronate-Terminated π-Conjugated Polymers Using Excess Dibromo Monomers,” Macromolecular Rapid Communications, vol. 37(1), pp. 79–85 (2016).
  • 3)M. Nojima, Y. Ohta, and T. Yokozawa, “Structural Requirements for Palladium Catalyst Transfer on a Carbon-Carbon Double Bond,” Journal of the American Chemical Society, vol. 137(17), pp. 5682–5685 (2015).
Affiliated Academic Organizations

T. Yokozawa:
The Chemical Society of Japan, The Society of Polymer Science, Japan, American Chemical Society, The Society of Synthetic Organic Chemistry, Japan.

Y. Ohta:
The Society of Polymer Science, Japan, The Chemical Society of Japan.

Current members
◯ Professors: 1 ◯ Assistant Professors: 1 ◯ Post-doctors: 1
◯ Postgraduates: 7 ◯ Undergraduates: 11

Facilities:Gas chromatography-mass spectrometry system, gas chromatograph, gel permeation chromatograph, gel permeation chromatography-multi-angle light scattering system, high-performance liquid chromatograph, glovebox.

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