Most Recent Publications
Engineering Ultrafast Molecular Rotors via Chalcogen bond
Chalcogen bonds are emerging σ-hole interactions with untapped potential in amphidynamic materials. We report the first crystalline molecular rotors held by chalcogen bonds and their ultrafast rotational dynamics. The rotator component 1,4-diazabicyclo[2.2.2]octane and phenylselenocyanate-based stators assemble via exceptionally short and highly directional Se···N contacts (Nc = 0.76–0.81; ∠NC–Se···N = 174–175 °). Solid-state 1H NMR T1 spin–lattice relaxation measurements reveal rotation at hundreds of MHz with low activation barriers (Ea = 1.22–2.78 kcal mol–1), in agreement with the packing coefficient and computational analysis. These findings highlight chalcogen bonds as a powerful tool for designing robust, crystalline molecular machines.
J. Am. Chem. Soc. 2026, 148, 18, 18591–18596
Three-dimensional imaging via quantum chain amplification in a crystalline two-photon adiabatic photocage
We report here a Dewar-benzene-1,2-dicarboxylic-acid monoester with a 7-hydroxycoumarin (7H) fluorescent cage (DB-7HC) that leverages two-photon excitation (TPE) to trigger an adiabatic triplet-state reaction that initiates a quantum chain capable of releasing up to 400 molecules of 7HC per excitation event. The chemical enhancement afforded by a TPE microscope enables precise, chemically amplified uncaging, which together with sensitive fluorescence detection results in high three-dimensional (3D) spatial resolution. Using a femtosecond pulse laser operating in the 690- to 770-nm range, this system allows for deep bulk activation with minimal scattering, with 7HC acting as a TPE antenna and triplet sensitizer and, once released, as a fluorescent reporter for real-time imaging. The high quantum yield and solid-state reactivity of the Dewar-benzene-1,2-dicarboxylic-acid monoester motif make it a promising probe for 3D microfabrication, patterning, optogenetics, and targeted drug delivery, with a demonstrated 1- to 5-μm spatial resolution.
Crystalline Thymine Dimers Splitting by an Interfacial Photomechanochemical Single Electron Transfer Chain Reaction
Splitting of the cis, syn thymine dimer (TD) into thymine (T) can be achieved in the solid state via an interfacial SET photomechanochemical reaction with N,N,N,N-tetramethyl-1,4-phenylenediamine (TMPD) as the photochemical reductant. Mechanical grinding enabled the uniform deposition of the TMPD sensitizer on the dimer surface, and photoirradiation of this solid–solid mixture (TD+TMPD) triggered electron transfer at the solid–solid interface that was propagated into the bulk of the crystal as a chain reaction. Variables explored included sensitizer loading and preparation strategies that included solid–solid mixing and the deposition of the photosensitizer onto the TD surface from solution. Clean solid-to-solid transformations were observed with product yields as high as ∼95%.
