The
Helping you react with chemical reactions

Issue11March2023

Controllingchemical reactions
with temperature

Controlling chemical
reactions with temperature
Temperature is very important for chemists to consider when developing new chemical reactions. The
temperature at which a reaction is performed can alter not only the speed of the reaction, but it canalso change the product that is formed! Temperature is closely related to energy, influencing molecular vibrations or the speed of a molecule’s motion. Additionally, calculating the energy of molecules
can help chemists better predict whether a reaction is possible and what products will be produced.

The barrier forpath B is too high,so molecules follow
path A which has
a lower energy
barrier.

The reaction canbe directed to path B
by heating the starting
molecules so they
have enough energy
to climb the higher
energy barrier.

1. Heat and temperature
We often experience the sensations of
hot and cold in our daily lives. Similar
to everyday objects around us, thetemperature of a molecule is raisedby heating it. Heat is a form ofenergy, and when a molecule
absorbs heat it gains energy andmoves with a greater speed. The
more quickly molecules move, themore they collide into each other.
This creates more chances for areaction to occur, speeding up theoverall rate of reaction.

2. Energy Barriers
In principle, chemical reactions do not begin on
their own. For example, when starting a fire, aspark is needed to get the combustion
reaction going. All chemical reactions
require some amount of external energy toget started, and this is called activationenergy. Activation energy acts as abarrier, preventing the reaction fromhappening on its own. However, if
enough energy is supplied to thestarting molecules, this barrier canbe overcome, and the reaction canproceed. Every reaction has adifferent activation energy barrier,and reactions with higher barriers
require more energy to get started.

on!
it
av
it
Ac
Quiz
Heating a moleculemakes it_.
Send us your answer!

A stop vibrating
B move more quickly
C less reactive

3.

Controlling reactions
with temperature

For some chemical reactions, it is possible
to obtain a different product from thesame starting materials by changingthe temperature at which thereaction is performed. In
chemistry, lower energy molecules
are more stable, so reactions
naturally proceed toward thelower energy product molecules(GOAL B instead of GOAL A).
However, sometimes theactivation energy barrier is highand the starting molecules don’t
have enough energy to overcome thatbarrier. In that case, the reaction willproceed along an alternate path with a lower
activation barrier (path A). By heating thereaction and providing enough energy toclimb the taller barrier, the reaction can becontrolled to follow path B.

4.

Optimizing reaction conditions
with computational chemistry

At ICReDD, computational chemists use
mathematics and quantum chemistry to calculate
the height of the energy barrier and theenergy of the product molecules. Using theArtificial Force Induced Reaction (AFIR)
method developed at ICReDD, researchers
can automatically search for and compute
all possible paths for a reaction. This caninform scientists of situations when
multiple products might form. Scientists
can then use the calculated energies of theproducts and energy barriers of thedifferent paths to help them optimizeexperimental conditions, such as temperature,
to get only the desired product. In this way,
computations enable scientists to find suitable
reaction conditions more quickly, speeding up new
chemical reaction discovery!

D lose energy

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

Selected Publications

ICReDD
N ews(from December 2022 to February 2023)

Ma rc h 2023

NewResearchers

Red-light
photoswitching of
indigos in polymer
thin films” Chem.
Sci. 2023

Automated chemical
reaction prediction:
now in stereo

Robots and A.I. teamup to discover highly
selective catalysts

Takano, Y. Harabuchi, S.

Graph neuralnetworks accelerate
AFIR-based
automated reaction
path search

Nagata, T. Gimadiev, A.

It Takes Two:cooperating catalysts
provide new routefor utilizing formate
salts( C.Y. Huang)

Maeda)( Y. Harabuchi, S. Maeda)

Varnek, B. List)( S.R. Mangaonkar,

https://www.icredd.hokudai.

https://www.icredd.hokudai.

https://www.icredd.hokudai.

https://www.icredd.hokudai.

H.Hayashi, H. Takano, S.

ac.jp/research/8687

ac.jp/research/8491

ac.jp/research/8594ac.jp/research/8645

Maeda, T. Mita)( T. Mita, H. Hayashi, H.

( N.Tsuji, P. Sidorov, Y.

https://www.icredd.hokudai.
ac.jp/research/8676

ChanduGopalakrishnan
Photoresponsive
Asymmetric Catalysis andRadical Transformations

Outreach・Visit by delegation from theUK Embassy in Tokyo led by
Deputy Head of Mission
Helen Smith

SymposiaAwards

・The 2nd Akira Suzuki Awards Ceremonyand 5th ICReDD International Symposium

・17th Annual HPC Innovation Award・72nd Annual Chemical Society ofJapan Award for Young Chemists

・Monthly Research Postcard(K. Kubota)

・The CATALYST Issue 10

Monthly
News Postcard

The CATALYST
10th issue(A. Lyalin)・2023 Thieme Chemistry Journals
Award (N. Tsuji)

Visit by delegation from the UK Embassy in Tokyo led
by Deputy Head of Mission Helen Smith

The 2nd Akira Suzuki Awards Ceremony

Researcher Profile

vol.11Min Gao
Associate Professor Gao is working
on computational catalysis. Her
research focuses on understanding
and developing catalytic reactions
at the atomic level by using computers.
Recently, she is also doing experiments based on the results of her
theoretical calculations.
Representative Papers:
J. Phys. Chem. C, 2021, 125, 19219-19228.
J. Phys. Chem. C, 2021, 125, 1334-1344.
J. Chem. Theo. Comp., 2014, 10, 1623-1630.

Short Biography
Associate Professor, Junior PI at ICReDD,Hokkaido University
Prof. Gao received her PhD from theGraduate School of Science in Hokkaido
University in 2012. She continued her
research work as a postdoc and joined
the Institute for Catalysis in Hokkaido
University as an assistant professor in
2018. She started her current position in
August 2022.

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
ICReDD held The 2nd Akira Suzuki Awards Ceremony and 5th ICReDD International Symposium onJanuary 11th, 2023. The 2nd Akira Suzuki Award was presented to John F. Hartwig, the Henry
Rapoport Professor of Chemistry at the University of California, Berkeley. The 2nd ICReDD Award
was presented to Kendall N. Houk, Distinguished Research Professor at the University ofCalifornia-Los Angeles.

Published in March 2023
Published by theInstitute for Chemical Reaction Design and Discovery (WPI-ICReDD)
Hokkaido University
North 21, West 10, Kita Ward, Sapporo, Hokkaido, 001-0021 Japan
Telephone: + 81-11-706-9646 (Public Relations)
Email address: public_relations@icredd.hokudai.ac.jp

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