Article
Chemistry, Physical
Andrea Albino, Stefano Benci, Matteo Atzori, Laura Chelazzi, Samuele Ciattini, Andrea Taschin, Paolo Bartolini, Alessandro Lunghi, Roberto Righini, Renato Torre, Federico Totti, Roberta Sessoli
Summary: The study focuses on the spin-phonon coupling in vanadyl-acetylacetonate using terahertz time-domain spectroscopy and density functional theory (DFT) calculations. By recording THz spectra at different temperatures and calculating anisotropic cell parameter variations, the observed anharmonic frequency shift was accurately explained.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Anna Drzewicz, Natalia Sokulska, Ewa Juszynska-Galazka, Aleksandra Deptuch, Malgorzata Jasiurkowska-Delaporte, Przemyslaw Kula
Summary: The phase behavior, vibrational and relaxation dynamics of the liquid crystal 2',3'-difluro-4-nonyl-4-heptyl-para-terphenyl (abbreviated as 7T9) were investigated using various techniques, including differential scanning calorimetry, polarized optical microscopy, X-ray diffraction, Fourier-transform absorption infrared spectroscopy, and broadband dielectric spectroscopy. Two-dimensional correlation analysis of infrared spectra was employed to study the changes in molecular arrangement and specific interactions during phase transitions. The compound exhibited two crystal phases and three liquid crystal phases, namely smectic C, smectic A, and nematic. The absorption band related to the bending vibrations of methyl groups was found to be sensitive to intra- and intermolecular interactions in different thermodynamic states of the 7T9 compound. Additionally, a low-frequency relaxation process following an Arrhenius-type behavior was observed in the high-temperature crystal phase.
Article
Chemistry, Physical
Marit R. Fiechter, Pi A. B. Haase, Nidal Saleh, Pascale Soulard, Benoit Tremblay, Remco W. A. Havenith, Rob G. E. Timmermans, Peter Schwerdtfeger, Jeanne Crassous, Benoit Darquie, Lukas F. Pasteka, Anastasia Borschevsky
Summary: This study presents a theory-experiment investigation on the helically chiral compounds Ru(acac)(3) and Os(acac)(3) as candidates for next-generation experiments in detecting molecular parity violation (PV) in vibrational spectra. By using relativistic density functional theory calculations, optimal vibrational modes with PV effects exceeding the projected instrumental sensitivity of the ultrahigh resolution experiment being constructed at the Laboratoire de Physique des Lasers in Paris by up to two orders of magnitude were identified. Preliminary measurements of the vibrational spectrum of Ru(acac)(3) were conducted as the initial steps towards the planned experiment.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Tzu-Jung Pan, Kelly A. Stephani
Summary: A rovibrationally state-specific collision model for the O2(Sigma g-3)+O(P3) system reveals different effects in dissociation and recombination reactions between various rovibrationally resolved models.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Tao E. Li, Abraham Nitzan, Joseph E. Subotnik
Summary: For a small fraction of hot CO2 molecules immersed in a liquid-phase CO2 thermal bath, forming collective vibrational strong coupling (VSC) between the C=O asymmetric stretch of CO2 molecules and a cavity mode accelerates hot-molecule relaxation. The acceleration is resonantly dependent on the cavity mode detuning, cooperatively dependent on Rabi splitting, and collectively scales with the number of hot molecules.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Toru Shiozaki, Bess Vlaisavljevich
Summary: Accurate computational vibrational analysis of the Cr-Cr bond in dichromium complexes using CASPT2 methods provides insights into the nature of the bonds and helps interpreting the low-energy region of the spectra. The authors demonstrate improved Cr-Cr distances with the use of IPEA shift and estimate anharmonicity along v(Cr-2) using normal mode sampling.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Hayato Shiba, Masatoshi Hanai, Toyotaro Suzumura, Takashi Shimokawabe, Takashi Shimokawabe
Summary: Recent developments in machine learning have made accurate predictions of the dynamics of slow structural relaxation in glass-forming systems possible. However, existing machine-learning models mainly focus on learning a single dynamic quantity and its relation to the structural features of glassy liquids. In this study, a graph neural network model called "BOnd TArgeting Network (BOTAN)" is proposed, which learns the relative motion between neighboring pairs of particles and the self-motion of particles. By relating the structural features to these two different dynamical variables, the model can autonomously discern the effects of different dynamical processes on the self-motion of particles undergoing slow relaxation, thus enabling high-precision prediction of slow structural relaxation in space and time.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Gabriel F. S. Fernandes, Marcelo A. P. Pontes, Francisco B. C. Machado, Luiz F. A. Ferrao
Summary: This study estimated the electronic structure trends of transition metal acetylacetonates through qualitative and quantitative methods. The qualitative description based on ligand field theory established a relationship between electron occupancy and system stability, while the quantitative method characterized low-lying electronic states. The stability of TM(AcAc)(n) was ranked using a stability index based on wavefunction parameters, showing good agreement with the qualitative results and guiding the selection of TM(AcAc)(n) for applications with varying stability requirements.
COMPUTATIONAL AND THEORETICAL CHEMISTRY
(2022)
Article
Optics
Anna L. Wang, Vladislav V. Serov, Andrei Kamalov, Philip H. Bucksbaum, Anatoli Kheifets, James P. Cryan
Summary: The study found that nuclear motion affects the photoionization of H-2 on an attosecond timescale, suggesting that nuclear-electronic coupling is crucial in the sudden ionization of molecules containing light atoms.
Article
Chemistry, Physical
Fu-You Lu, Zhe-Sheng He, Nian-Zu She, Atsushi Yabushita, Daiki Uchida, Yutaka Maeda, Takayoshi Kobayashi
Summary: By using ultrashort visible pulse laser, the electronic relaxation and vibrational dynamics of non-substituted SWCNT, alkylated SWCNT, and annealed alkylated SWCNT were studied. The results showed that alkylation does not affect the intraband relaxation rate, but excess chemical modification inhibits it. The interband relaxation rate is the same for all three samples. Short time Fourier transform analysis visualizes the energy transfer and molecular structure change during the interband transition.
Article
Chemistry, Physical
Nishant Kumar Pathak, Yui Konno, Ying Kuan Ko, Yutaka Maeda, Takayoshi Kobayashi, Atsushi Yabushita, Bhaskar Kanseri
Summary: Ultrafast spectroscopy was used to compare purified and non-purified single-walled carbon nanotubes (SWCNTs). Three relaxation processes with different rates were observed. The fastest rate was attributed to intraband relaxation, while the other two rates corresponded to interband relaxation. Additionally, intermolecular vibrational energy transfer between SWCNTs with different chiralities was found only in the non-purified sample.
Article
Chemistry, Physical
Zuxin Jin, Joseph E. Subotnik
Summary: A new scheme is proposed for modeling molecular nonadiabatic dynamics near metal surfaces, utilizing the charge-transfer character of such dynamics. This scheme allows the construction of an efficient reduced representation for the electronic structure, and modification of the FSSH approach to include electronic relaxation. The resulting FSSH-ER method is validated across a wide range of coupling strengths, with plans to integrate it with ab initio electronic structure calculations in future work.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Materials Science, Multidisciplinary
Christian Lacroix, Kaan Oguz, John Michael David Coey, David Menard
Summary: The substitution of iron atoms by chromium in CoFeB films has been proposed to reduce the critical current density J(c) for current-driven magnetization switching in spin transfer torque devices by reducing its magnetization. The effect of Cr on the magnetic damping has been investigated through ferromagnetic resonance (FMR) measurements. It was found that introducing Cr increases the spin-orbit damping while reducing the magnetic relaxation rate. Additionally, the presence of Cr inhibits internal fluctuations of the magnetization, reducing the two-magnon damping.
Article
Materials Science, Multidisciplinary
Christian Lacroix, Kaan Oguz, John Michael David Coey, David Menard
Summary: The substitution of iron atoms by chromium in CoFeB films has been proposed to reduce the critical current density J(c) for current-driven magnetization switching in spin transfer torque devices by reducing its magnetization. The effect of Cr on the magnetic damping has remained elusive. Ferromagnetic resonance (FMR) measurements were used to study the different mechanisms of FMR damping in Co40Fe40-xCrxB20 thin films. The results showed that the addition of Cr increases the spin-orbit damping but reduces the magnetic relaxation rate.
Article
Thermodynamics
Minoru Yamamoto, Norihiro Onodera, Junichi Sakabe, Chang Yi Kong, Toshitaka Funazukuri
Summary: The infinite dilution binary diffusion coefficient of chromium (III) acetylacetonate in supercritical carbon dioxide was measured at various temperatures and pressures. The data showed deviations from the hydrodynamic equation at higher temperatures or lower viscosities, corresponding to the gas-like region. The accuracy of predicting the data was improved by a modified Schmidt number correlation.
FLUID PHASE EQUILIBRIA
(2022)
Article
Chemistry, Multidisciplinary
Catia Correia, Jose Martinho, Ermelinda Macoas
Summary: Carbon dots doped with Eu3+ ions were synthesized and their interaction and luminescence properties were characterized by vibrational spectroscopy and UV-vis excitation spectroscopy. The Eu3+ ions are strongly coordinated with the carboxylate groups at the surface of the Cdots and incorporated within the nanographene network in the carbon core. The luminescence of the Cdots is strongly quenched by Hg2+ and Ag+, and a ratiometric sensor can be built using their luminescence intensities ratio.
Article
Chemistry, Multidisciplinary
Ana M. Santiago, Carla I. M. Santos, Leandro M. O. Lourenco, Ines F. A. Mariz, Joao P. C. Tome, Ermelinda Macoas
Summary: Supramolecular hybrids of graphene quantum dots and phthalocyanine dyes were investigated as turn-OFF-ON photoluminescence nanosensors for detecting ds-DNA, showing high sensitivity and selectivity in comparison to other carbon-based nanosensors previously reported for DNA detection.
Article
Chemistry, Physical
Marco Reale, Alice Sciortino, Marco Cannas, Ermelinda Macoas, Arthur H. G. David, Carlos M. Cruz, Araceli G. Campana, Fabrizio Messina
Summary: Nanographenes (NGs) have unique properties that combine the characteristics of graphene and molecular features, such as bright visible photoluminescence. However, the heterogeneity of most NGs hinders our understanding of their fundamental properties. This study investigates the optical response of three curved hexa-peri-hexabenzocoronene (HBC) derivatives obtained by atomically precise synthesis routes, allowing for a direct comparison of their spectroscopic features and the role played by different edge chemistry.
Article
Materials Science, Biomaterials
Carla I. M. Santos, Monica Cicuendez, Gil Goncalves, Laura Rodriguez-Perez, M. Teresa Portoles, M. Amparo F. Faustino, M. Angeles Herranz, M. Graca P. M. S. Neves, Jose M. G. Martinho, Ermelinda M. S. Macoas, Nazario Martin
Summary: In this study, the biocompatibility and safety of functionalized nanodiamonds (NDs) were investigated through the assessment of the pro-inflammatory response of RAW-264.7 macrophages exposed to new nanodiamonds@corrole hybrids. The results showed that the hybrids had no pro-inflammatory effects on the macrophage cell line, making them an ideal candidate for various biomedical applications.
JOURNAL OF MATERIALS CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Romain Chevigny, Efstratios D. Sitsanidis, Johanna Schirmer, Eero Hulkko, Pasi Myllyperkio, Maija Nissinen, Mika Pettersson
Summary: A nanoscale infrared (IR) spectroscopy study was conducted to assess the heterogeneity and supramolecular assembly of a two-component supramolecular gel. Near-field IR spectroscopy revealed differences in the secondary structures and non-covalent interactions at different nano-locations of the gel network. The study found that a beta-sheet arrangement and strong hydrogen bonding are dominant in the gel, with an intense pi-pi stacking contribution at the crossing point of fibers. Near-field nanospectroscopy can be a powerful tool for distinguishing non-covalent interactions and advancing the spectroscopic assessment of supramolecular gels.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Efstratios D. Sitsanidis, Lara A. L. Dutra, Johanna Schirmer, Romain Chevigny, Manu Lahtinen, Andreas Johansson, Carmen C. Piras, David K. Smith, Marja Tiirola, Mika Pettersson, Maija Nissinen
Summary: In this study, the Fmoc-F/GO hybrid hydrogel was formed by combining Fmoc-F amino acid with graphene oxide (GO) flakes for the first time. GO flakes did not affect Fmoc-F self-assembly but modulated the gel's elasticity and accelerated its formation. The hybrid hydrogel exhibited significant bactericidal activity against Gram-negative Escherichia coli (E. coli), but intermittent bacterial recovery due to the inoculum effect was observed.
Article
Chemistry, Multidisciplinary
Sarah Klingler, Benedikt Bagemihl, Alexander K. Mengele, Simon Kaufhold, Pasi Myllyperkioe, Jussi Ahokas, Mika Pettersson, Sven Rau, Boris Mizaikoff
Summary: Currently, the efficient and economical utilization of photosensitizers and catalysts based on rare earth metals in artificial photosynthesis is a major concern. Although repairing inactivated catalysts is a potential solution, it remains a challenge. The study introduces an innovative in situ technique using non-invasive rotational Raman spectroscopy to accurately monitor initially evolved hydrogen and gas reaction products after active repair, providing valuable insights into the mechanism of active repair during light-driven catalysis and enabling the identification of relevant mechanistic details and innovative repair strategies.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Kyunglim Pyo, Maria Francisca Matus, Eero Hulkko, Pasi Myllyperkio, Sami Malola, Tatu Kumpulainen, Hannu Hakkinen, Mika Pettersson
Summary: Understanding the dynamics of FRET in fluorophore-functionalized nanomaterials is crucial for their applications in biomedical imaging and optical sensing. This study investigates the structural dynamics of noncovalently bound azadioxotriangulenium dye and gold nanoclusters, revealing their energy transfer mechanism and providing new insights at an atomistic level. Experimental and computational methods were used to resolve distinct subpopulations involved in the energy transfer process, and molecular dynamics simulations explained the observed phenomena. The observed energy transfer rates were in accordance with the well-known 1/R(6) distance dependence for FRET.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Johanna Schirmer, Romain Chevigny, Aleksei Emelianov, Eero Hulkko, Andreas Johansson, Pasi Myllyperkio, Efstratios D. Sitsanidis, Maija Nissinen, Mika Pettersson
Summary: This study investigates the effects of laser-oxidized single layer graphene (SLG) surface on the self-assembly of amphiphilic gelator N-fluorenylmethoxycarbonyl-l-phenylalanine (Fmoc-Phe) towards a gel-SLG interface. The laser oxidation modulates the hydrophobicity/hydrophilicity levels on the SLG surface. Various microscopy techniques were used to assess the effects of surface properties on the organization of Fmoc-Phe fibers at the SLG-gel interface. The findings underline the sensitivity of assembled structures to surface properties and demonstrate the potential of the characterization approach for the development of bionic devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Aku Lampinen, Erich See, Aleksei Emelianov, Pasi Myllyperkio, Andreas Johansson, Mika Pettersson
Summary: We introduce a novel method called pulsed femtosecond laser-induced two-photon oxidation (2PO) to locally adjust the sensitivity of solution gated graphene field-effect transistors (GFETs) without damaging the carbon network of chemical vapor deposition (CVD) grown graphene. By using 2PO, the sensitivity of GFETs reached (25 +/- 2) mV pH(-1) in BIS-TRIS propane HCl (BTPH) buffer solution, corresponding to an oxidation level with a Raman peak intensity ratio I(D)/I(G) of 3.58. The sensitivity of non-oxidized, residual PMMA contaminated GFETs was 20-22 mV pH(-1). Initially, the sensitivity decreased to (19 +/- 2) mV pH(-1) (I(D)/I(G) = 0.64) due to the removal of PMMA residue by laser irradiation. Through 2PO, the functionalization of CVD-grown graphene with oxygen-containing chemical groups can be locally controlled, leading to improved performance of GFET devices. The GFET devices were made HDMI compatible to facilitate their connection with external devices and enhance their applicability.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Microbiology
Marjo Haapakoski, Aleksei Emelianov, Dhanik Reshamwala, Mira Laajala, Jenni Tienaho, Petri Kilpelainen, Jaana Liimatainen, Tuula Jyske, Mika Pettersson, Varpu Marjomaki
Summary: This study aimed to functionalize cellulose materials with tannic acid to prevent viral infectivity. The results showed that tannic acid-functionalized materials had efficient antiviral efficacy against different viruses and could reduce infectivity. Additionally, the study revealed an interaction between the tannic acid-functionalized materials and the viruses. This research is of great significance for enhancing biosafety and biosecurity by reducing pathogen persistence.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Johanna Schirmer, Ester Iatta, Aleksei V. Emelianov, Maija Nissinen, Mika Pettersson
Summary: Biosensors based on graphene and bio-graphene interfaces have gained popularity due to their excellent electronic and mechanical properties. This study investigates the catalytic activity of horseradish peroxidase immobilized on graphene surfaces with varying degrees of oxidation. The results show that the catalytic activity decreases with increasing oxidation, indicating surface-related effects on enzyme activity.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Erich See, Elsa Korhonen, Maija Nissinen, Mika Pettersson
Summary: In this study, a novel boron-dipyrromethene (BODIPY)-caged amine was synthesized and its release behavior with green light was demonstrated both in solution and adhered to a graphene surface. The non-covalent conjugation of a BODIPY-capped PPG amine with a graphene surface opens up possibilities for space-selective functionalization.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kyunglim Pyo, Maria Francisca Matus, Sami Malola, Eero Hulkko, Johanna Alaranta, Tanja Lahtinen, Hannu Hakkinen, Mika Pettersson
Summary: This study presents a novel strategy for tailoring fluorescent pH sensors based on gold nanoclusters by regulating their pK(a) values. The researchers controlled the pK(a) values of gold nanoclusters by adjusting their sizes, leading to different pH response ranges for the fluorescent dye KU. They also found that the interaction of p-MBA ligands on the nanocluster surface plays a significant role in the pH response behavior.
NANOSCALE ADVANCES
(2022)
Article
Chemistry, Multidisciplinary
Sandra Miguez-Lago, Ines F. A. Mariz, Miguel A. Medel, Juan M. Cuerva, Ermelinda Macoas, Carlos M. Cruz, Araceli G. Campana
Summary: In this study, a novel superhelicene structure with near-infrared circularly polarized luminescence and good photoluminescence performance was described. Compared to similar structures reported previously, this superhelicene exhibits higher luminescence efficiency and brightness.