CLL (Coimbra, Portugal)

CLL aims to promote and support the use of lasers in the study of the interactions between radiation and matter at the molecular level. Specialized on photochemical, photophysical and spectroscopic studies, from the infrared through the ultraviolet, covering timescales from femtoseconds at room temperatures to ultra slow processes at cryogenic temperatures.
Research highlights

Chemistry Department, University of Coimbra
3000-535 Coimbra, Portugal


Luís Arnaut

CLL focuses on areas such as photodynamic therapy, organic polymeric and inorganic photovoltaics, optical sensors, light-emitting devices, matrix isolation spectroscopy and photochemistry, conformation dependent reactivity, hot vibrational chemistry, properties of transient species, photocatalysis, DNA delivery and skin permeation, and photochemistry to art conservation.

Industrial Collaboration

Ongoing project with LaserLeap Tech, SA , "FOTOVID Viral photo-inactivation in the control of the COVID-19 pandemic”, (Sep 2020 – Jun 2021).

Amyloid aggregation

Using amyloid intrinsic fluorescence, spinning-disk confocal microscopy and scattering experiments the aggregation pattern of Aβ42 in presence of a novel class of potential multitarget anti-Alzheimeŕs drugs was screened. Together with in vitro and in vivo results towards cholinergic deficiency and mitochondrial systems, a lead structure was clearly identified, validating the multiple disease-relevant targets strategy used. [Bioorg. Chem. 107, 104596 (2021)]

Cyclometalated Pt(II) Complexes

The photophysical characterization of five novel cyclometalated platinum(II) compounds containing five different alkynyl-chromophores was achieved. It was observed that the spectral and photophysical characteristics of the cyclometalated platinum(II) complexes (Pt–Ar) are essentially associated with the platinum-cyclometalated unit. Room-temperature emission of the Pt–Ar complexes was attributed to phosphorescence in agreement with DFT calculations.
[Inorg. Chem. 59, 8220–8230 (2020)]

N,N′-disubstituted indigo derivatives

Femtosecond transient absorption spectrometerA comprehensive characterization of the excited state properties of five N,N′-substituted indigo (Ind) derivatives (acetyl-, benzoyl-, methoxybenzoyl-, nitrobenzoyl- and chlorobenzoyl-) was undertaken in various solvents and temperatures. In the excited state, rotation around the central double bond was found with N,N′-diacetylindigo (DAI) and N,N′-dibenzoilindigo (DBI) derivatives. [Dyes and Pigments 176, 108197 (2020)]

Conformational switching

The molecule 4-amino-2,6-dimethoxypryimidine was subjected to conformer switching studies. Consistent with theory, two conformers were observed after deposition of the molecule onto the cold matrix window. Subsequent UV irradiation of the matrix caused the formation of a third and new rotamer. The results from the project have been included in an MSc thesis. The project also served as training and exchange of knowledge in matrix-isolation spectroscopy and inspiration for the renovation of the laboratory in Copenhagen to allow for laser irradiation and recording of both infrared and UV-VIS signatures.

Projects performed by external users >>

Further application highlights

Lasers and Cancer Lasers and Water Lasers for Cultural Heritage


CLL is:Fluorescence Upconversion and 2D-IR spectrometers

  1. a leader in time-resolved photoacoustics
  2. a leader in matrix isolation spectroscopy, photochemistry and solid-state hot vibrational chemistry
  3. a reference laboratory for time-resolved single photon counting
  4. equipped for state-of-the-art femtosecond transient absorption measurements with NIR/VIS/NIR detection
  5. a unique facility integrating fs/ps/ns measurements of transients in solutions, films, supercritical fluids, cultured cells flow cytometry, and low temperature matrices. CLL recently installed photoacoustic tomography in an associated animal facility, a Two-Dimensional Infrared spectrometer (2D-IR) and a broadband fluorescence upconversion spectrometer.

Equipment offered to external users
  • PhotoacousticsPhD students setting up a TCSPC measurement
    • Calorimetry flow cells
    • Transducers and hydrophone for photoacoustic detection.
    • Pulsed excitation sources
  • Lasers
    • Nd-Yag lasers with harmonic generators
    • Nitrogen laser
    • Dye laser
    • Diode lasers at 633 nm, 649 nm, 748 nm (10-40 mW), 748 nm (100 mW).
    • Ar+continuous Laser
    • Two fs-laser amplifiers with broadband optical parametric amplifiers (OPA)
  • Spectrometers
    • Broadband pump-probe femtosecond transient absorption spectrometer
    • Femtosecond fluorescence upconversion spectrometer
    • Two-Dimensional Infrared, 2D-IR, spectrometer
    • Raman spectrometer (Nicolet DXR SmartRaman), with commutable excitation lasers in the visible and IR range.
    • High-resolution Raman mapping/imaging system, covering all spectral range from near-IR to UV, and with submicron spatial resolution.
    • UV/visible spectrometer (ScanSci) interfaced with the cryostats.
    • Ramon mapping: confocal microspectrometer
    • Fluorescence spectrophotometers and fluorimeters, phosphorimeters etc.
    • UV-VIS-NIR absorption spectrophotometers
  • Nanosecond and picosecond time correlated single-photon counting systems
  • Cryostats capable of providing temperatures down to 4 K.
  • Oven for higher-temperature work
  • Infrared mapping/imaging Nicolet system
  • Monochromator for irradiation experiments at low temperature and different broadband sources (Xe/(Hg), Xe, D).
  • Supercritical fluid spectroscopy
  • Fluorescence microscope