Hydrogen bonds (H-bonds) can be interpreted as a classical electrostatic interaction or covalent chemical bond if the is strong enough. As result, short H-bonds exist at an intersection between qualitatively different bonding descriptions, with few experimental methods to understand this dichotomy. The [F-H-F]- ion represents bare H-bond, whose distinctive vibrational potential in water revealed femtosecond two-dimensional infrared spectroscopy. It shows superharmonic behavior of proton...

Most symmetric quadrupolar molecules designed for two-photon absorption behave as dipolar in the S1 electronic excited state. This is usually explained by a breakup of symmetry However, origin this process and its dynamics are still not fully understood. Here, excited-state breaking molecule with D-π-A-π-D motif, where D A electron donating accepting units, observed real time using ultrafast transient infrared spectroscopy. The nature relaxed state was found to strongly depend on solvent...

Abstract Symmetry‐breaking charge transfer upon photoexcitation of a linear A‐π‐D‐π‐A molecule (D and A being electron donating accepting groups) could be visualized using ultrafast time‐resolved infrared spectroscopy by monitoring the CN stretching modes on units. Whereas in apolar solvents, S 1 state remains symmetric quadrupolar, symmetry breaking occurs within ca. 100 fs polar solvents as shown presence two bands, instead one with splitting that increases polarity. In protic is...

Because of its crucial role in many areas science and technology, photoinduced electron transfer is the most investigated photochemical reaction. Despite this, several important questions remain open. We present recent efforts to answer some them, which concern both inter- intramolecular processes. The decisive factor that allowed these issues be successfully addressed was use time-resolved infrared (TRIR) spectroscopy. Many different transient species, such as tight loose ion pairs (TIPs...

The influence of the length push–pull branches quadrupolar molecules on their excited-state symmetry breaking was investigated using ultrafast time-resolved IR spectroscopy. For this, dynamics an A-π-D-π-A molecule compared with those ADA analogue, where same electron donor (D) and acceptor (A) subunits are directly linked without a phenylethynyl π-spacer. spatial distribution excitation visualized in real time by monitoring C≡C C≡N vibrational modes localized spacer units, respectively. In...

Symmetry breaking of the excited state a linear quadrupolar acceptor-donor-acceptor molecule was investigated using time-resolved infrared spectroscopy in 55 solvents allowing influence several solute-solvent interactions to be examined separately. No symmetry found nonpolar irrespective their refractive index, indicating that differences dispersion between two arms do not suffice induce an asymmetric distribution excitation. However, observed nondipolar but like benzene extent can as large...

TRIR spectroscopy identifies the low-energy ligand-field state in relaxation cascade for ruthenium(<sc>ii</sc>) polypyridyl complexes.

The hydrogen-bond induced quenching of an excited chromophore is visualised by probing O–H vibrations the interacting solvent molecules.

Abstract The nature of the electronic excited state many symmetric multibranched donor–acceptor molecules varies from delocalized/multipolar to localized/dipolar depending on environment. Solvent-driven localization breaks symmetry and traps exciton in one branch. Using a combination ultrafast spectroscopies, we investigate how such excited-state breaking affects photochemical reactivity quadrupolar octupolar A–( π -D) 2,3 with photoisomerizable A– –D branches. Excited-state is identified by...

A simple model has been developed to describe the symmetry-breaking of electronic distribution AL-D-AR type molecules in excited state, where D is an electron donor and AL AR are identical acceptors. The origin this process usually associated with interaction between molecule solvent polarization that stabilizes asymmetric dipolar a larger charge transfer on one side than other. An additional mechanism involving direct Coulomb charges acceptors proposed. At same time, coupling two degenerate...

Aqueous electrolytes in the super-concentrated regime, where water and ions are present a similar concentration, have recently drawn considerable interest for their potential application electrochemical systems, such as Li+ batteries. In this classical theories structure properties of electrolyte solutions break down, even fundamental solution morphology on molecular length scale can be unclear, with specific ion effects often driving properties. Here, we study role ion–ion interactions...

Understanding the mechanisms of charge transport in batteries is important for rational design new electrolyte formulations. Persistent questions about ion battery electrolytes are often framed terms vehicular diffusion by persistent ion-solvent complexes versus structural through breaking and reformation contacts, i.e., solvent exchange events. Ultrafast two-dimensional (2D) IR spectroscopy can probe processes directly via evolution cross-peaks on picosecond time scales. However,...

The influence of torsional disorder around the ethynyl π-bridges a linear D-π-A-π-D molecule on nature its S1 excited state was investigated using ultrafast time-resolved infrared spectroscopy. By tuning pump wavelength throughout ← S0 absorption band, subpopulations with different extents asymmetry could be excited. In nonpolar solvents, equilibrated is symmetric and quadrupolar independently initial degree distortion. Photoexcitation distorted molecules followed by planarization...

Acetonitrile has emerged as a solvent candidate for novel electrolyte formulations in metal-ion batteries and supercapacitors. It features bright local C≡N stretch vibrational mode whose infrared (IR) signature is sensitive to battery-relevant cations (Li+, Mg2+, Zn2+, Ca2+) both pure form the presence of water admixture across full possible range concentrations from dilute superconcentrated regime. Stationary time-resolved IR spectroscopy thus emerges natural tool study site-specific...

The excited-state dynamics of an aniline–triazine electron donor–acceptor dyad with alkyne spacer has been investigated using a combination ultrafast broadband mid-IR and visible transient absorption fluorescence spectroscopies. IR data reveal the occurrence efficient to allene isomerization time constant increasing from few hundreds femtoseconds picoseconds solvent viscosity. This process is faster than vibrational cooling Franck–Condon excited state, indicative nonequilibrium dynamics....

A thorough understanding of the microscopic mechanism excited-state proton transfer (ESPT) and influence solvent environment on its dynamics are great fundamental interest. We present here a detailed investigation an ESPT to (DMSO) using time-resolved broadband fluorescence transient absorption spectroscopies. All species resolved spectrally kinetically global target analysis based two-step Eigen-Weller model. Reversibility initial short-range producing excited contact ion pairs (CIP*) is...

Superconcentrated electrolytes have emerged as a promising class of materials for energy storage devices, with evidence that high voltage performance is possible even water the solvent. Here, we study changes in hydrogen bonding network induced by dissolution lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) concentrations ranging from dilute to superconcentrated regimes. Using time-resolved two-dimensional infrared spectroscopy, observe progressive disruption water-water bond and...

The electronic absorption spectrum of 3-hydroxyflavone (3HF) in various solvents exhibits a long-wavelength (LW) band, whose origin has been debated. excited-state dynamics neutral and basic solutions 3HF alcohols upon excitation this LW band investigated using combination fluorescence up-conversion transient vibrational spectroscopies. ensemble results reveals that, solutions, the population two excited species with similar spectra but very different lifetimes, namely 40-100 ps 2-3 ns,...

H-bonding with the solvent affects significantly photoisomerisation of Methyl Orange.

The aqueous proton is a common and long-studied species in chemistry, yet there currently intense interest devoted to understanding its hydration structure transport dynamics. Typically described terms of two limiting structures observed gas-phase clusters, the Zundel H5O2+ Eigen H9O4+ ions, less clear due heterogeneity hydrogen bonding environments room-temperature structural fluctuations water. linear infrared (IR) spectrum, which reports on configurations, challenging interpret because it...

Complexation of three 3-hydroxychromone derivatives bearing a nitrogen-containing heterocyclic moiety in the position 2 chromone bicycle − benzimidazole, quinoline, and 2,5-diphenyloxazole, with mercury(II) ions is reported. Formation chelate complexes metal cations coordinated cavity formed by 3-OH 4-C═O groups was shown, as well possibility side heteroatom participation binding ions. High sensitivity to mercury 2,5-diphenyloxazole-substituted elucidated, allowing detect Hg2+ below maximum...

Abstract Symmetry‐breaking charge transfer upon photoexcitation of a linear A‐π‐D‐π‐A molecule (D and A being electron donating accepting groups) could be visualized using ultrafast time‐resolved infrared spectroscopy by monitoring the CN stretching modes on units. Whereas in apolar solvents, S 1 state remains symmetric quadrupolar, symmetry breaking occurs within ca. 100 fs polar solvents as shown presence two bands, instead one with splitting that increases polarity. In protic is...

Time-resolved broadband fluorescence facilitates direct observation of reaction intermediates in excited-state proton transfer to solvent protic and aprotic solvents.

Abstract Intermolecular H‐bonding dynamics around a photoexcited quadrupolar dye is directly observed using transient 2D‐IR spectroscopy. Upon solvent‐induced symmetry breaking, the H‐bond accepting abilities of two nitrile end‐groups change drastically, and in extremely protic (superprotic) solvents, tight complex forms at one end. The time evolution 2D C≡N lineshape methanol points to rapid, 2–3 ps, spectral diffusion due fluctuations network. Similar behavior superprotic solvent shortly...