Molecular Photochemistry and Photophysics

Molecular Photochemistry and Photophysics group utilizes time-resolved laser spectroscopy from femtosecond to millisecond time scales on various molecular systems.

Blue laser beam shining on cuvettes emitting fluorescence at various colors.

Research group type

Research group

Core fields of research

Basic natural phenomena and mathematical thinking

Research areas

Nanoscience Center

Second quantum revolution

Chemical Nanoscience

Faculty

Faculty of Mathematics and Science

Department

Department of Chemistry

Research group description

Molecular Photochemistry and Photophysics Group is headed by Dr. Tatu Kumpulainen. We are a member of the LaserLab-NSC and the at the Ģ��ֱ��.

Our research is focused on detailed investigations of excited-state proton-transfer (ESPT) reactions in different media. In particular, we are interested in the influence of the environment on acidity, proton transfer and proton diffusion in liquid solutions and heterogeneous media. Most of our research is carried out on “super” photoacids, compounds that are weak acids in their electronic ground-states but become extremely strong acids in their excited-state. In our work, we utilize several optical spectroscopic techniques and quantum chemical calculations to investigate both the ground and excited-state properties of photoacids and other solvatochromic dyes. Read more about our Research topics and check our latest Publications below for further details.

Keywords: proton transfer, proton diffusion, photochemistry, photophysics, photoacids, time-resolved spectroscopy

Research topics

Solvation dynamics can have a direct influence on ultrafast photochemical reactions (e.g. proton transfer) and is therefore of key importance for our research. We utilize femtosecond broadband FLuorescence UP-conversion Spectroscopy (FLUPS) for detailed investigations on solvation dynamics in polar liquids and heterogeneous media. We are interested in how the chemical structure of solutes and dielectric properties of solvents influences the time scale of the solvent relaxation. In addition, we are developing novel methods for the analysis of the broadband fluorescence data.

Excited-state proton transfer (ESPT) in organic solvents forms the core of our research interests. We utilize a large range of optical spectroscopic methods for detailed investigations on the mechanism and dynamics of ESPT reactions. Our work relies on “super” photoacids, acids that have negative excited-state acidities and are able to deprotonate in several organic solvents. Our research questions are focused on the influence of solvation dynamics as well as macroscopic solvent parameters (e.g. dielectric constant, acidity, viscosity etc.) on the ground-state acidity and ESPT to solvent and organic bases.

Last research topic is focused on studying acidity, proton transfer and proton diffusion in biological media such as phospholipid liposomes and protein environment. The research on liposomes relies on specially designed photoacids that can the anchored on the membrane surface. Due to the thorough understanding of the influence of the environment on ESPT, the properties of the photoacids in these media are expected to provide direct information about the local biological environment. Therefore, the main research questions are related to the properties of the biological media rather than to the proton transfer itself.

Publications

Summer School Report: Jyväskylä Summer School Course on Ultrafast Spectroscopy
K. M. Yallum* and T. Kumpulainen*
Atomistic View of the Energy Transfer in a Fluorophore-Functionalized Gold Nanocluster
K. Pyo, M. F. Matus, E. Hulkko, P. Myllyperkiö, S. Malola, T. Kumpulainen*, H. Häkkinen* and M. Pettersson*
Spectroscopic Investigation of Photophysics and Tautomerism of Amino- and Nitroporphycenes
I. Mbakara, A. Gajewsks, A. Listkowski, M. Kijak, K Nawara, T. Kumpulainen, E. Vauthey and J. Waluk*
Photoinduced Electron Transfer in a Porphyrin–Fullerene Dyad at a Liquid Interface
J. Sissaoui, A. Efimov, T. Kumpulainen*, and E. Vauthey*
30th International Conference on Photochemistry (ICP2021): An Introduction by the Guest Editors
A. Fürstenberg*, T. Kumpulainen
Conference Report: SCS Photochemistry Section Symposium, Online Conference, June 19, 2020
T. Kumpulainen*
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Broadband Fluorescence Reveals Mechanistic Differences in Excited-State Proton Transfer to Protic and Aprotic Solvents
P. Verma, A. Rosspeintner, B. Dereka, E. Vauthey, and T. Kumpulainen*
Propyl Acetate/Butyronitrile Mixture is Ideally Suited for Investigating the Effect of Dielectric Stabilization on (Photo)Chemical Reactions
P. Verma, A. Rosspeintner, and T. Kumpulainen*
Untying the Photophysics of Quinolinium-Based Molecular Knots and Links
K. Caprice, A. Aster, F.B.L. Cougnon*, and T. Kumpulainen*
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In collaboration with , we characterized the physico-chemical properties of a family of quinolinium-based molecular links and knots. Our results showed that the properties are progressively modified as the tightness of the knots increases.
Accelerating the Shuttling in Hydrogen-Bonded Rotaxanes: Active Role of the Axle and the End Station
T. Kumpulainen,* M.R. Panman, B.H. Bakker, M. Hilbers, S. Woutersen,* and A.M. Brouwer*

We reported on the synthesis and mechanistic characterization of the world's fastest molecular shuttle. Furthermore, use of excited-state proton transfer from a photoacid as the driving mechanism of the molecular shuttle was demonstrated for the first time.
Tuning Symmetry Breaking Charge Separation in Perylene Bichromophores by Conformational Control
A. Aster, G. Licari, F. Zinna, E. Brun, T. Kumpulainen, E. Tajkhorshid, J. Lacour, and E. Vauthey*
Conference Report: SCS Photochemistry Section Meeting, Fribourg, June 14, 2019
T. Kumpulainen,* A. Fürstenberg*
Spectroscopic Study of a Cinchona Alkaloid-Catalyzed Henry Reaction
T. Kumpulainen,* J. Qian, and A.M. Brouwer*
Influence of Solvent Relaxation on Ultrafast Excited-State Proton Transfer to Solvent
T. Kumpulainen,* A. Rosspeintner, B. Dereka, and E. Vauthey*
Probe Dependence on Polar Solvation Dynamics from fs Broadband Fluorescence
T. Kumpulainen, A. Rosspeintner, and E. Vauthey*
Ultrafast Elementary Photochemical Processes of Organic Molecules in Liquid Solution
T. Kumpulainen, B. Lang, A. Rosspeintner, and E. Vauthey*
Selective Co-Encapsulation Inside a M₆L₄ Cage
S.H.A.M. Leenders, R. Becker, T. Kumpulainen, B. de Bruin, T. Sawada, T. Kato, M. Fujita, and J.N.H. Reek*
Complexes of a Naphthalimide Photoacid with Organic Bases, and Their Excited-State Dynamics in Polar Aprotic Organic Solvents
T. Kumpulainen,* B.H. Bakker, and A.M. Brouwer*
Synthesis and Spectroscopic Characterization of 1,8-Naphthalimide Derived “Super” Photoacids
T. Kumpulainen, B.H. Bakker, M. Hilbers and A.M. Brouwer*
Excited-State Proton Transfer and Ion Pair Formation in a Cinchona Organocatalyst
T. Kumpulainen and A.M. Brouwer*
Effects of Carbon-Metal-Carbon Linkages on the Optical, Photophysical, and Electrochemical Properties of Phosphametallacycle-Linked Coplanar Porphyrin Dimers
Y. Matano,* K. Matsumoto, H. Hayashi, Y. Nakao, T. Kumpulainen, V. Chukharev, N.,V. Tkachenko, H. Lemmetyinen,* S. Shimizu, N. Kobayashi,* D. Sakamaki, A. Ito, K. Tanaka, and H. Imahori
Independence and Inverted Dependence on Temperature of Rates of Photoinduced Electron Transfer in Double-Linked Phthalocyanine-Fullerene Dyads
H. Lemmetyinen,* T. Kumpulainen, M. Niemi, A. Efimov, J. Ranta, K. Stranius, and N.V. Tkachenko
Close Proximity Dibenzo[a,c]phenazine-Fullerene Dyad: Synthesis and Photoinduced Singlet Energy Transfer
R.K. Dubey,* T. Kumpulainen, A. Efimov, N.V. Tkachenko, and H. Lemmetyinen
Synthesis and Characterization of Monoisomeric 1,8,15,22-Substituted (A₃B and A₂B₂) Phthalocyanines and Phthalocyanine-Fullerene Dyads
J. Ranta,* T. Kumpulainen, H. Lemmetyinen, and A. Efimov
Interlayer Energy Transfer Between Perylene Diimide and Phthalocyanine Monolayers
H. Lehtivuori,* T. Kumpulainen, A. Efimov, H. Lemmetyinen, F. Würthner, and N.V. Tkachenko
Electronic Energy Harvesting Multi BODIPY-Zinc Porphyrin Dyads Accommodating Fullerene as Photosynthetic Composite of Antenna-Reaction Center
E. Maligaspe, T. Kumpulainen, N.K. Subbaiyan, M.E. Zandler, H. Lemmetyinen, N.V. Tkachenko,* and F. D′Souza*
Ultrafast Singlet-Singlet Energy Transfer in Self-Assembled via Metal-Ligand Axial Coordination of Free-Base Porphyrin-Zinc Phthalocyanine and Free-Base Porphyrin-Zinc Naphthalocyanine Dyads
E. Maligaspe, T. Kumpulainen, H. Lemmetyinen, N.V. Tkachenko,* N.K. Subbaiyan, M.E. Zandler, and F. D′Souza*
Photodynamics of Charge Separation and Recombination in Solid Alternating Films of Phthalocyanine or Phthalocyanine–Fullerene Dyad and Perylene Dicarboximide
H. Lehtivuori,* T. Kumpulainen, M. Hietala, A. Efimov, H. Lemmetyinen, A. Kira, H. Imahori, and N.V. Tkachenko
Photoinduced Electron Transfer in Langmuir-Blodgett Monolayers of Double-Linked Phthalocyanine-Fullerene Dyads
H. Lehtivuori,* T. Kumpulainen, A. Efimov, H. Lemmetyinen, A. Kira, H. Imahori, and N.V. Tkachenko

Theses:

Proton-Transfer Reactions in "Super" Photoacids and Supramolecular Aseemblies
T. Kumpulainen, PhD thesis, University of Amsterdam, The Netherlands, 2015. ()

Doctoral students and postdoctoral researchers

We currently don't have any vacant positions. However, there are several funding possibilities, such as Marie Skłodowska-Curie Fellowships, Academy Research Fellow and various foundations, to support postdoctoral researchers. If you are interested in applying, we are willing to help.

Students

We are always looking for motivated students interested in optical spectroscopy and encourage students to enquire about possible internships and B.Sc./M.Sc. projects in our group. The group offers various opportunities to work with state-of-the-art optical spectroscopy methods. If you are interested in joining our group, please contact Dr. Tatu Kumpulainen directly with a brief description of why you would like to work with us.

Members

Amar Raj

Doctoral Researcher

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