Torsional Structural Relaxation Caused by Pt-Pt Bond Formation in the Photoexcited Dimer of Pt(II) N ̂ C ̂ N Complex in Solution.

[Pt(NCN)MeCN] (NCN = 1,3-di(2-pyridyl)benzene, MeCN = acetonitrile) forms oligomers in the ground state due to metallophilic interactions, and a Pt-Pt bond is formed with photoexcitation. Ultrafast excited-state dynamics of the [Pt(NCN)MeCN] dimer in acetonitrile is investigated by femtosecond time-resolved absorption (TA) and picosecond emission spectroscopy. The femtosecond TA signals exhibit 60 cm oscillations arising from the Pt-Pt stretching motion in the S dimer.

An Energy-Tunable Dual Emission Mechanism of the Hybridized Local and Charge Transfer (HLCT) and the Excited State Conjugation Enhancement (ESCE).

Molecular design of dual-fluorescent probes requires precise adjustment of the energy levels of two excited states and the energy barrier between them. While the hybridized local and charge-transfer (HLCT) state has been recently focused as an important excited state for high emission efficiency with a tunable energy level, a dual emission involving the HLCT state has been only achieved with the excited-state intramolecular proton transfer (ESIPT) system. Here, a series of dual-fluorescent molecules involving an HLCT excited state with the excited-state conjugation enhancement (ESCE) motif is presented as the first case.

Atmospheric concentrations of per- and polyfluoroalkyl substances and their emissions at a waste recycling facility producing refuse-derived paper and plastics densified fuel.

To better understand the types and concentrations of per- and polyfluoroalkyl substances (PFAS) emitted into the air from waste recycling facilities that produce refuse-derived paper and plastics densified fuel (RPF) from industrial waste, we conducted an air sampling campaign at a waste recycling facility in Japan. Both passive and active air sampling were conducted, and the samples collected were used to quantify the PFAS emitted into the air during the production of RPF. Overall, few ionic PFAS were detected in the air at the facility; however, high levels of neutral PFAS (8.

Room-Temperature Solution Fluorescence Excitation Correlation Spectroscopy.

Single-molecule fluorescence spectroscopy is a powerful tool for investigating the physical properties of individual molecules, yet elucidating the fast fluctuation dynamics of freely diffusing single molecules in solution at room temperature, where a variety of chemical and biological processes occur, remains challenging. In this study, we report on fluorescence excitation correlation spectroscopy of room-temperature solutions, which enables the study of spontaneous fluctuation of the excitation spectrum with microsecond time resolution. By employing Fourier transform spectroscopy with broadband femtosecond pulses and time-correlated single-photon counting, we achieved fluorescence excitation spectroscopy of a room-temperature solution at the single-molecule level.