Iron(II)oxalate Dihydrate—Humboldtine: Synthesis, Spectroscopic and Structural Properties of a Versatile Precursor for High Pressure Research

Iron(II)oxalate dihydrate FeC2O4 × 2 H2O—humboldtine is not only an important synthetic intermediate, but also a key building block for the preparation of various advanced materials. Interestingly, FeC2O4 × 2 H2O can be transformed readily into phase-pure siderite FeCO3. The importance of siderite for earth sciences, in particular for the understanding of the deep carbon cycle of our planet, is paramount. The availability of high-quality single crystals of FeC2O4 × 2 H2O is crucial for diffraction or spectroscopic studies at high pressure. The present article describes a versatile synthetic approach to single crystals of FeC2O4 × 2 H2O and its deuterated analogue starting from metallic iron together with a complete characterization of the products obtained. The same protocol has been employed successfully for the preparation of 57FeC2O4 × 2 H2O, as required for Möβbauer spectroscopy. In addition, the pressure-dependence of the crystal and molecular structure of the title compound was investigated up to p ≥ 20 GPa.

High-pressure sapphire capillary cell for synchrotron single-crystal X-ray diffraction measurements to 1500 bar

A new sapphire capillary pressure cell for single-crystal X-ray diffraction measurements at moderate pressures (200−1500 bar; 1 bar = 100 kPa) has been developed and optimized for use on beamline I19 at Diamond Light Source. The three-component cell permits optical centring of the crystal and in situ pressure modification to a precision of 1 bar. Compression of hexamethylenetetramine and its deuterated analogue to 1000 bar was performed, showcasing the accuracy and precision of the measurements, and highlighting evidence of a geometric isotope effect.

Synthesis of Hydroxyethyl Tetrathiatriarylmethyl Radicals OX063 and OX071

<p>We report the synthesis of hydroxyethyl tetrathiatriarylmethyl radicals OX063 and its deuterated analogue OX071 for biomedical EPR applications.<br></p>

Synthesis of Hydroxyethyl Tetrathiatriarylmethyl Radicals OX063 and OX071

<p>We report the synthesis of hydroxyethyl tetrathiatriarylmethyl radicals OX063 and its deuterated analogue OX071 for biomedical EPR applications.<br></p>

Exploring the Mechanism of Olfactory Recognition at the Initial Stage by Modeling the Emission Spectrum of Electron Transfer

Olfactory sense remains elusive regarding the primary reception mechanism. Some studies suggest that olfaction is a spectral sense, the olfactory event is triggered by electron transfer (ET) across the odorants at the active sites of odorant receptors (ORs). Herein we present a Donor-Bridge-Acceptor model, proposing that the ET process can be viewed as an electron hopping from the donor molecule to the odorant molecule (Bridge), then hopping off to the acceptor molecule, making the electronic state of the odorant molecule change along with vibrations (vibronic transition). The odorant specific parameter, Huang–Rhys factor can be derived from ab initio calculations, which make the simulation of ET spectra achievable. In this study, we revealed that the emission spectra (after Gaussian convolution) can be acted as odor characteristic spectra. Using the emission spectrum of ET, we were able to reasonably interpret the similar bitter-almond odors among hydrogen cyanide, benzaldehyde and nitrobenzene. In terms of isotope effects, we succeeded in explaining why subjects can easily distinguish cyclopentadecanone from its fully deuterated analogue cyclopentadecanone-d28 but not distinguishing acetophenone from acetophenone-d8.

Quantum-Induced Symmetry-Breaking in the Deuterated Dihydroanthracenyl Radical

The hydrogen-atom adduct with anthracene, 9-dihydroanthracenyl radical (C₁₄H₁₁), and its deuterated analogue, have been identified by laser spectroscopy coupled to time-of-flight mass spectrometry, supported by time-dependent density functional theory calculations. The electronic spectrum of 9-dihydroanthracenyl radical exhibits an origin band at 19115 cm^-1 and its ionization energy was determined to be 6.346(1) eV. The spectra reveal a low-frequency vibrational progression corresponding to a mode described by a butterfly-inversion. In the deuterated analogue, a zero-point-energy imbalance along this coordinate is found to lead to a doubling of the observed spectral lines in the progression. This is attributed to quantum-induced symmetry breaking as previously observed in isotopologues of CH₅⁺.