Crystalline γ-aminobutyric acid (GABA) exhibits unusual thermal behavior in a low-frequency lattice vibration that occurs at 37.2 cm −1 at 290 K but decreases dramatically by 34.0% when the sample is cooled to 78 K. Lattice vibrations in molecular crystals are indicators of intermolecular force characteristics, and the extraordinary temperature sensitivity of this vibration offers new insight into the local environment within the solid. Solid-state density functional theory simulations of the GABA crystal have found this anomalous frequency shift is based in unexpected differences in the strengths of the intermolecular hydrogen bonds that are cursorily the same. This was accomplished through mapping of the potential energy surfaces governing the terahertz-frequency motions of the GABA solid and use of the quasiharmonic approximation to model the response of all the lattice vibrations to temperature-induced unit cell volume changes brought about through the anharmonic character of the intermolecular interactions. The analysis reveals that the vibration in question is rotational in nature and involves the significant distortion of a specific weak intermolecular N−H•••O hydrogen bond in the crystal that results in its unique thermal response.

A RHENIUM(I) NAPHTHALIMIDE COMPLEX [RE(CO)3(5-PAN)CL] (RE(5-PAN)); 5-PAN = 1-(1,10-PHENANTHROLINE)-4-NITRO-NAPHTHALIMIDE) WAS SYNTHESIZED AND CHARACTERIZED UTILIZING MALDI-TOF MASS SPECTROMETRY, FT-IR, RAMAN, 1H AND 13C NMR, ELEMENTAL ANALYSIS, ELECTRONIC ABSORBTION AND EMISSION SPECTROSCOPY,...

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4-Acetamido-2,2,6,6-tetramethyl-1-oxopiperidinium tetrafluoroborate (Bobbitt's salt) effectively activates electron rich alkenes and promotes the addition of anilines. This transformation provides a direct, transition metal free method for amino-oxidation of alkenes under mild conditions. The relative stereochemistry of the amino-oxidation is influenced by solvent effects, with both the syn and anti amino-oxidation products being accessible from identical starting materials. File list (3)download file view on ChemRxiv AminoOx-Manuscript.pdf (582.97 KiB) download file view on ChemRxiv AminoOx-SuppInfo.pdf (6.39 MiB) download file view on ChemRxiv CCDC2031980.cif (0.96 MiB)