Walshhensley4057

Potent ice nucleating organic crystals display an increase in nucleation efficiency with pressure and memory effect after pressurization that set them apart from inorganic nucleants. These characteristics were proposed to arise from an ordered water monolayer at the organic-water interface. It was interpreted that ordering of the monolayer is the limiting step for ice nucleation on organic crystals, rendering their mechanism of nucleation nonclassical. Despite the importance of organics in atmospheric ice nucleation, that explanation has never been investigated. selleck Here we elucidate the structure of interfacial water and its role in ice nucleation at ambient pressure on phloroglucinol dihydrate, the paradigmatic example of outstanding ice nucleating organic crystal, using molecular simulations. The simulations confirm the existence of an interfacial monolayer that orders on cooling and becomes fully ordered upon ice formation. The monolayer does not resemble any ice face but seamlessly connects the distinct hydrogen-bonding orders of ice and the organic surface. Although large ordered patches develop in the monolayer before ice nucleates, we find that the critical step is the formation of the ice crystallite, indicating that the mechanism is classical. We predict that the fully ordered, crystalline monolayer nucleates ice above -2 °C and could be responsible for the exceptional ice nucleation by the organic crystal at high pressures. The lifetime of the fully ordered monolayer around 0 °C, however, is too short to account for the memory effect reported in the experiments. The latter could arise from an increase in the melting temperature of ice confined by strongly ice-binding surfaces.We have designed and synthesized a new type of distorted nanographene by Diels-Alder and Scholl reactions that contains one dibenzobistetracene (DBT, 1) core and two end-capping corannulene units. Single-crystal X-ray diffraction analyses demonstrate that nanographene 1 contains two [5] helicene subunits with a dihedral angle of 62°, consequently leading to the distorted DBT core. In addition, the photophysical properties and (non)aromaticity of 1 were investigated by the absorption and emission spectra in combination with theoretical calculations.Library searching is a powerful technique for detecting peptides using either data independent or data dependent acquisition. While both large-scale spectrum library curators and deep learning prediction approaches have focused on beam-type CID fragmentation (HCD), resonance CID fragmentation remains a popular technique. Here we demonstrate an approach to model the differences between HCD and CID spectra, and present a software tool, CIDer, for converting libraries between the two fragmentation methods. We demonstrate that just using a combination of simple linear models and basic principles of peptide fragmentation, we can explain up to 43% of the variation between ions fragmented by HCD and CID across an array of collision energy settings. We further show that in some circumstances, searching converted CID libraries can detect more peptides than searching existing CID libraries or libraries of machine learning predictions from FASTA databases. These results suggest that leveraging information in existing libraries by converting between HCD and CID libraries may be an effective interim solution while large-scale CID libraries are being developed.We report here a C-H homoallylation reaction of aromatic ketones with methylenecyclopropanes (MCPs) only using a catalytic amount of Fe(PMe3)4. A variety of aromatic ketones and MCPs are applicable to the reaction to form ortho-homoallylated aromatic ketones selectively via regioselective scission of the three-membered rings. The homoallylated products are amenable to further elaborations, providing functionalized 1,2-dihydronaphthalenes.Mo was successfully introduced into a vanadotungstate (VT-1), which is a crystalline microporous zeolitic transition-metal oxide based on cubane clusters [W4O16]8- and VO2+ linkers (MoxW4-x. x number of Mo in VT-1 unit cell determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES)). It was confirmed that W in the cubane units was substituted by Mo. The resulting materials showed higher microporosity compared with VT-1. The surface area and the micropore volume increased to 296 m2·g-1 and 0.097 cm3·g-1, respectively, for Mo0.6W3.4 compared with the those values for VT-1 (249 m2·g-1 and 0.078 cm3·g-1, respectively). The introduction of Mo changed the acid properties including the acid amount (VT-1 1.06 mmol g-1, Mo0.6W3.4 2.18 mmol·g-1) and its strength because of the changes of the chemical bonding in the framework structure. MoxW4-x showed substantial catalytic activity for the selective catalytic reduction of NO with NH3 (NH3-selective catalytic reduction (SCR)) at a temperature as low as 150 °C.For a mechanically tough proton exchange membrane, a composite membrane incorporated with a porous polymer substrate is of great interest to suppress the ionomer swelling and to improve the dimensional stability and mechanical strength of the ionomers. For the composite membranes, good impregnation of substrate-incompatible ionomer solution into the substrate pores still remains one of the challenges to be solved. Here, we demonstrated a facile process (surface treatment with solvents compatible with both substrate and the ionomer solution) for the fabrication of the composite membranes using polytetrafluoroethylene (PTFE) as a porous substrate and poly(arylene ether sulfone) (SPAES) as a hydrocarbon-based (HC) ionomer. Appropriate solvents for the surface treatment were sought through the contact angle measurement, and it was found that alcohol solvents effectively tuned the surface property of PTFE pores to facilitate the penetration of the SPAES/N-methyl-2-pyrrolidone (NMP) solution into ∼300 nm pores of the substrate. Using this simple alcohol treatment, the SPAES/NMP contact angle was reduced in half, and we could fabricate the mechanically tough PTFE/HC composite membranes, which were apparently translucent and microscopically almost void-free composite membranes.