The
Helping you react with chemical reactions

Issue16
June
2024

Environmentally friendly
reaction development:
Force is the key?

Environmentally friendly reaction development: Force is the key?
Materials and products that make our lives more convenient also put stress on the environment in the form of hazardous chemicals that result from the treatment of plastic
garbage and other waste products. Instead of simply enjoying the convenience brought to our lives, we should think about the future and work to develop new materials andnew technologies that are kind to the planet, an endeavor that is also included in the United Nations Sustainable Development Goals. In this issue, we introduce ICReDD
research that focuses on safety and low environmental impact.

Comm on pl a ce ra di cOzone layer
destructionals

UV lightFF
Cl C ClCl CCl Freon
ClCl

Mechanochemistry

Cl radical

Chemical reactions can be caused
simply by hitting a mixture ofchemicals with a hammer.

New radical formed:
chlorine monoxide

Cl radicalCl

When the bond
betweenA and B breaks...

O3

ClO

O2OzoneA
Cut with
Cut withB
Radical→ Ion

Example of a radical reaction:
Initiation Reaction

ClClChlorine

Energyfrom heator light→: electron

2ClCl radical

Chain reaction
HCl radical attacks
methaneH C HHMethane

Cl radicalH Cl

The newly formed methyl radical
reacts with a chlorine molecule toform another Cl radical. Suchreactions can chain together likefalling dominos and in this way
radicals are able to promote
chemical reactions.

mm on pl a ce ra di c

Chloromethane(methyl chloride)

H CHCl Cl

New radical
formed:Methyl radicalChlorine

Methyl radicalattacks Chlorinec h ano ch emi s t r yals

Gel nails
UV light

UV light triggers
a reaction between
the initiator andother molecules thathardens the gel.

Commonplace radicals
Resin materials made by radical reactions
are used as adhesives and water resistantmaterials in smartphones and smart watches.

LiquidHardenedClH

H

Hydrogen chlorideMeCo

HH CClRadicals can be generated with mechanicalforce. At ICReDD, we succeeded in using
radicals generated from a shredded up
grocery bag to reduce the toxicity
of a hazardous chemical!

1. Mechanochemistry
When you imagine a chemical reaction,
it is common to think of mixing
chemicals together in a liquid andheating the mixture or shining it with alight to cause a reaction. However, inthe field of mechanochemistry, solids
are hit or smashed together via
mechanical force to cause a reaction,
hardly using any liquid or any energy
from heat or light. Specialized machines
called ball mills provide the mosteffective mixing. A ball, typically madeof metal, is placed in a metal jar alongwith chemical substances. The ball mill rapidly
shakes the jar, pulverizing the chemical solids and mixing them together sufficiently tocause a reaction. Alternatively, even a method as simple as hitting chemicals with ahammer can enable a reaction. It may sound like incredibly tough work is being donein these experiments, but as we mentioned in Issue 7 of The Catalyst, methods likethis are gaining attention for being safer and more environmentally friendly since they
reduce the amount solvent being used and the amount of waste products generated.

2. Radical reactions
HH
Now we will talk about a type
H C ClClH C Hof chemical reaction called aHClradicalH
radical reaction. First,
Chloromethane
Methane(methyl chloride)chemical bonds occur when
two atoms each donate anelectron to create an electron
H ClH
pair that is shared between
Cl Cl
H C
Hydrogenthe atoms. When a chemicalchloride
HChlorine
bond breaks, it can break in
Methyl radical
two different ways. Either thebond is broken unevenly, and both electrons from the bond stay with one of thefragments, or the bond is broken evenly, with one electron going to each fragment. For
the latter case, the result is the formation of two radicals, which are molecules or atoms
that have an unpaired electron. Unpaired electrons are usually unstable and seek abonding partner, thus radicals easily react with other radicals or molecules, and they canoften trigger a chain reaction. When radicals react with other molecules, an electron pairis formed at the radical, stabilizing it. However, since the molecule supplied one of its
electrons, there is now an unpaired electron on the molecule, turning it into a new
radical. This new radical can then bond with another molecule, turning that bonding
partner into a radical. This bond formation and transfer of the unpaired electron canrepeat many times like falling dominoes, until two radicals react with each other to forma stable electron pair and end the chain reaction.

tiAc t i vaon!

Quiz
Radicals are generated by:electron
A one-to-one
sharing that creates a bondpairs splitting
B electron
evenly when a bond breaks
positive ion and a
C anegativeion creating a bondpairs splitting
D electrons
unevenly when a bond breaks

Send us your answer!

3. Commonplace radical reactions 4. Combining radicals andAll you need is the first domino and theforce to knock it over in order to set off
the rest of the dominoes to fall. For aradical reaction, that first domino piece isa molecule that easily forms radicals,called an initiator. The force that knocks
over that piece is energy from heat, light,
or mechanical force. Have you ever heardof the term “ozone depletion”? Theozone layer in the stratosphere keeps theamount of UV rays that reach the earth’s
surface at a suitable level, protecting theecosystem. A pollutant called Freon, which wasonce commonly used as a coolant in refrigerators and a propellant in aerosol cans,forms chlorine radicals when hit by UV light. A single one of these chlorine radicals
can destroy 100,000 ozone molecules through a chain reaction, so there are now
regulations across the globe to abolish the use of Freon. In a more everyday
example, UV light also provides the energy to initiate the radical reaction that
hardens gel fingernails. The liquid gel consists of small molecules mixed with an
initiator molecule. When exposed to a UV lamp, a radical reaction connects the small
molecules together into large polymer molecules, which causes the gel to solidify.

mechanochemistry

Luminescent Gel
ICReDD has developed unique technologies bycombining mechanochemistry and radicalreactions. In one case, a gel was developedthat emits light in places where it wassubjected to a strong force such as pulling orpressing. The damage this force induces at thenanoscale can lead to deterioration that cannot
be seen with the naked eye, but the lightemission from damaged areas could be used toNanoscale damage to the gel
contribute to the development of materials. Incauses those areas to emit lighta separate project, ICReDD researchers
via a radical reaction, making
damaged areas visible.
discovered a method which uses a ball mill toinitiate radical reactions using common plastic
materials as the initiator. They were even able
to use shredded up bits of a plastic grocery bag as a radical initiator and promote areaction that can reduce the toxicity of hazardous chemicals. If we can reuse the plastic
bag waste produced from our daily lives to help with the treatment of hazardous
chemicals, we could tackle two environmental problems in one fell swoop!

Check ourInstagram
highlights forthe answer
to the quiz!
#ReactWithUs@ICReDDconnectNew Researchers

ICReDDN e wsJ un e 2024

Wataru Matsuoka

Kalipada Jana

MartinKoki Tsuchiya

Computational chemistry,
virtual screening

Radical chemistry,
asymmetric catalysis

Machine learning,
drug discovery

Photoacoustic imaging,organic synthesis

Chenghan Sun

Tavinder Singh

Kosaku Tanaka III

Keisuke Wada

Balasubramaniyan Sakthivel

Machine learning,catalysis

Organic Synthesis

Organometallic chemistry,
photocatalysisHost-guest chemistry,
supramolecular chemistry

Computational chemistry,
informatics

Selected Publications (from March 2024 to May 2024)
Bridging the Gap: FromFrequent Molecular
Changes to Observable
Phenomena(Y. Nagahata, M. Kobayashi, S. Maeda, T. Taketsugu,
T. Komatsuzaki)
https://www.icredd.hokudai.ac.jp/research/11263

Artificial intelligence-based, on-the-fly
Raman spectroscopy
method shows promise for
rapid medical diagnosis

Outreach・Visit from National Chung Hsing
University led by Prof. Kuan - Jiuh Lin・Monthly Research Postcard
・The C ATALYST Issue 15(K. Tabata, J. E. Clement, T. Komatsuzaki)
https://www.icredd.hokudai.ac.jp/research/10794

Visit from National Chung Hsing University led byProf. Kuan-Jiuh LinAward
Light stimulates a new twist for synthetic chemistry (Y. Harabuchi, S. Maeda)
https://www.icredd.hokudai.ac.jp/research/10644

・MEXT Minister’s The Young
Scientists’ Award(Harabuchi, Takahashi)Monthly Research
Postcard

The CATALYST
15 th Issue

Researcher Profile

vol.16

Hailong FanSpecially Appointed Associate Professor Hailong Fan’s research focuses on
the design and synthesis of functionalhydrogels. He works on controlling thearrangement of building block molecules in polymers to achieve underwater adhesion of hydrogels.
Representative Papers:
Nat. Commun. 2019, 10, 5127.
Proc. Natl. Acad. Sci. U.S.A. 2022, 119, e2206685119.
Adv. Mater. 2021, 33, 2102983.

Short Biography
Dr. Fan received his Ph.D from Renmin Universityof China in 2017. He then joined Prof. Jian Ping
G o n g ’s g r o u p a t H o k k a i d o U n i v e r s i t y a s a
postdoctoral research fellow. He was promoted
to assistant professor in 2020 and speciallyappointed associate professor in 2022. Hereceived the Polymer Research Encouragement
Award from the Society of Polymer Science Japan(SPSJ) in 2021.

About ICReDD
The development of new chemical reactions is intrinsically entangled with the prosperity ofhumanity and the preservation of the environment. A recent example of such transformative chemical reactions with profound impact is cross-coupling reactions, the discovery of which was awarded
with the 2010 Nobel Prize in Chemistry. These reactions are used to produce approximately 20% of
all medicinal reagents, and almost all liquid crystalline and organic electroluminescent materials.
The industrial use of these chemical reactions contributes ~60 trillion yen per annum to the global
economy. The development of new chemical reactions thus significantly affects the evolution ofsociety.
ICReDD is the Institute for Chemical Reaction Design and Discovery, a WPI center at Hokkaido
University where researchers from different disciplines combine their strengths to take full control
over chemical reactions. The institute was born out of the realization that the purposeful design ofchemical reactions requires cross-sectional collaborations at every step. Working on such a fundamental natural process, quantum-chemical computations, information technology, modern experimental techniques, and the development of advanced materials can no longer be separate fields if
we want to achieve significant breakthroughs. Rather, they have to become part of a diverse
toolbox for truly integrated research.

The Catalyst is inspired by catalysts used inchemistry to bring molecules together, to reduce
reaction barriers, and to activate molecules—to makereactions happen faster. In this spirit, this poster series
should enable its readers to make the connection
between chemical reactions and the wellbeing of oursociety, and to look at the world in a new way, seeing
how chemical reactions and chemistry shape the world
around them. And if we can take this opportunity tointroduce ourselves, too, this may also catalyze newfriendships and opportunities. #ReactWithUs

React With Us!
To stay up to datewith what’s happening at ICReDD,
follow us on our social media channels:@ICReDDconnect

Top On April 6th, Minister Masahito Moriyama from the Ministry of Education, Culture, Sports,
Science and Technology visited ICReDD. He was welcomed by Hokkaido University President
Kiyohiro Houkin, and representatives of ICReDD including Director Satoshi Maeda and Administrative
Director Koichiro Ishimori, and they held a discussion. Bottom During the subsequent tour of thefacilities, Specially Appointed Assistant Professor Seiji Akiyama demonstrated the process of using anautomated synthesis robot for chemical synthesis in ICReDDʼ s Smart Lab.

Published in June 2024
Published by theInstitute for Chemical Reaction Design and Discovery (WPI-ICReDD)
Hokkaido University
North 21, West 10, Kita Ward, Sapporo, Hokkaido, 001-0021 JapanTelephone: + 81-11-706-9646 (Public Relations)
Email address: public_relations@icredd.hokudai.ac.jp

https://www.icredd.hokudai.ac.jp/