Ion pairs and solubility related to ion-pairing in water influence many processes in nature and in synthesis including efficient drug delivery, contaminant transport in the environment, and self-assembly of materials in water. Ion pairs are difficult to observe spectroscopically because they generally do not persist unless extreme solution conditions are...
The heterogeneous reactions of ambient particulate matter (PM)-bound polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) with NO₃/N₂O₅, OH radicals, and O₃ were studied in a laboratory photochemical chamber. Ambient PM[subscript 2.5] and PM₁₀ samples were collected from Beijing, China and Riverside, California, and exposed under simulated atmospheric long-range transport conditions...
We, for the first time, employ magnesiothermic reaction to convert microwave-irradiated graphite oxide to pure graphene. The magnesiothermic reaction raises the carbon to oxygen atomic ratio from 22.2 to 165.7 and maintains a high surface area. The new strategy demonstrates an efficient method for obtaining highly pure graphene materials.
This research is the first to quantify complex PAH mixtures in NIST SRMs using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/ToF-MS), with and without extract cleanup, and reports previously unidentified PAH isomers in the NIST SRMs. We tested a novel, high orthogonality GC column combination (LC-50×NSP-35), as...
We report an experimental and theoretical study of single-molecule inner-shell photoemission measured over an extended range of photon energies. The vibrational intensity ratios I (nu = 1)/I (nu = 0) from the C 1s photoelectron spectra of carbon monoxide, although mostly determined by the bond length change upon ionization, are...
We use femtosecond stimulated Raman spectroscopy (FSRS) to illuminate the choreography of intermolecular excited-state proton transfer (ESPT) of photoacid pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) in water. The multidimensional reaction coordinate responsible for photoacidity is revealed to involve sequential activation of characteristic skeletal motions during the ca. 1 ps preparation stage preceding...
This manuscript describes the role of non-classical hydrogen bonds (NCHBs), specifically C–H···O interactions, in modern synthetic organic transformations. Our goal is to point out the seminal examples where C–H···O interactions have been invoked as a key stereocontrolling element and to provide predictive value in recognizing future and/or potential C–H···O interactions...
We demonstrate the generation of broadband up-converted multicolor array (BUMA) in a thin BK7 glass slide using two noncollinear weak near-IR laser pulses with various crossing angles. The BUMA signal arises from cubic nonlinear χ⁽³⁾:χ⁽³⁾ processes via cascaded four-wave mixing of the two incident beams. Broad and continuous tunability of...
The solid solution of In₂Fe₂₋ₓGaₓCuO₇ (space group P6₃/mmc) was synthesized and investigated through X-ray diffraction and magnetic susceptibility studies. Limited changes to the lattice parameters were observed as a result of the similar ionic radii for Fe³⁺ and Ga³⁺ in the trigonal bipyramidal (TBP) crystallographic site. An increase in the...
The electrochemical intercalation of tetra-n-alkylammonium (TAA) cations into graphite is investigated using galvanostatic reduction and cyclic voltammetry in TAABr/ dimethylsulfoxide (DMSO) electrolytes. Structural and compositional analyzes by X-ray diffraction, thermogravimetric and elemental analyzes show that stable graphite intercalation compounds (GICs) are formed with highly-flattened TAA cation bilayers for (C₅H₁₁)₄N⁺, (C₆H₁₃)₄N⁺,...